planning and control earthwork

PLANNING AND CONTROLLING OF EARTHWORK OPERATION MULTI-STOREY PROJECT

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NONAME OF STUDENT AND

HAND-PHONE NOUITM NO SIGNATURE

1MD ABDULHADI

MOHAMMED SOPAFI

0122090493

2009249132

2ILYAS MUSTAPHA

MOHAMMAD

0176671030

2009647962

3 RIDUAN MOHD TAHIR

0135013035

2009667776

4NURHAFIZAH FATIN

A RAHMAN

0194190164

2009697746

5 SITI ATIEKAH JUSOH

0179226492

2009815488

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Contents1 LIST OF FIGURE................................................................................................................4

2 PROJECT..........................................................................................................................6

2.1 PROJECT DESCRIPTION............................................................................................7

2.2 SITE ORGANISATION CHART..................................................................................10

2.3 INTRODUCTION.....................................................................................................11

3 PLANNING OF EARTHWORK OPERATION MULTI-STOREY PROJECT...............................12

3.1 INTRODUCTION.....................................................................................................12

3.2 DESIGN STAGE.......................................................................................................13

3.2.1 SCOPE............................................................................................................13

3.2.2 GENERAL........................................................................................................13

3.2.3 TECHNICAL RESPONSIBILITIES........................................................................14

3.2.4 SITE INVESTIGATIONS....................................................................................15

3.2.5 PLANNING AND DESIGN................................................................................17

3.2.6 FINAL DOCUMENTATION...............................................................................24

3.2.7 PROTECTION OF THE WORKS........................................................................25

3.2.8 CLEARING AND GRUBBING............................................................................29

3.2.9 Disposal of Material.......................................................................................30

3.3 PLANNING STAGE..................................................................................................31

3.3.1 COST ESTIMATED...........................................................................................31

3.3.2 METHOD STATEMENT AND PROJECT PLANNING...........................................39

3.3.3 CONSTRUCTION METHOD AND USE OF PLANT.............................................49

4 CONTROLLING FOR OPERATION OF EARTHWORK.........................................................58

4.1 INTRODUCTION.....................................................................................................58

4.1.1 SURFACE LEVELLING STATION (MONUMENT)...............................................59

4.1.2 SETTELEMENT PLATE (ROD EXTENSOMETER)................................................60

4.1.3 MAGNETIC EXTENSOMETER..........................................................................61

4.1.4 USBR SETTLEMENT GAUGE............................................................................61

4.1.5 PIEZOMETER..................................................................................................62

4.2 SLOPE PROTECTION...............................................................................................63

4.2.1 STABILIZATION OF CUT SLOPES.....................................................................64

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4.3 Methods of Groundwater Control.........................................................................65

4.3.1 Sumps and Ditches........................................................................................65

4.3.2 Deep-Well Systems........................................................................................67

4.3.3 Wellpoint Systems.........................................................................................71

4.3.4 Vertical Sand Drains.......................................................................................79

4.3.5 Electro-Osmosis.............................................................................................80

4.3.6 Cutoffs...........................................................................................................82

4.4 CONSTRUCTION PROCEDURES..............................................................................90

4.4.1 SPECIFICATIONS.............................................................................................90

4.4.2 FILL CONSTRUCTION......................................................................................91

4.4.3 INSPECTION AND QUALITY CONTROL............................................................93

4.5 CASE STUDY...........................................................................................................95

4.5.1 SLOPE STABILIZATION/ SLOPE PROTECTION..................................................95

4.5.2 DEWATERING SYSTEM.................................................................................100

4.5.3 TRAFFIC CONTROL.......................................................................................104

4.5.4 SAFETY CONTROL.........................................................................................107

4.5.5 SETTLEMENT CONTROL...............................................................................110

4.5.6 DOCUMENTATION CONTROL......................................................................111

5 CONCLUSION.............................................................................................................116

6 Bibliography................................................................................................................117

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1 LIST OF FIGURE

FIGURE 1 SUBANG SOHO PROJECT..........................................................................................................6FIGURE 2 SITE PLAN OF SOHO PROJECT..........................................................................................9FIGURE 3 SITE LAYOUT - SOHO PROJECT.....................................................................................9FIGURE 4 THE SOIL THAT WILL EXCAVATE. (35, 000M3)....................................................................38FIGURE 5 CRITICAL PATH METHOD....................................................................................................48FIGURE 6 DEWATERING OPEN EXCAVATION BY SUMP AND DITCH.......................................................................66FIGURE 7 SUBMERSIBLE PUMP FOR DEWATERING AN EXCAVATION.....................................................................66FIGURE 8 DEEP WELL SYSTEM FOR DEWATERING AN EXCAVATION IN SAND..........................................................67FIGURE 9 DEEP WELLS WITH AUXILIARY VACUUM SYSTEM FOR DEWATERING A SHAFT IN STRATIFIED MATERIALS.........68FIGURE 10 PLAN OF A TYPICAL WELLPOINT SYSTEM.........................................................................................71FIGURE 11 A TYPICAL WELLPOINT SYSTEM AT SITE..........................................................................................71FIGURE 12 USE OF WELLPOINTS WHERE SUBMERGENCE IS SMALL......................................................................72FIGURE 13 DRAINAGE OF AN OPEN DEEP CUT BY MEANS OF A MULTISTAGE WELLPOINT SYSTEM..............................73FIGURE 14 VACUUM WELLPOINT SYSTEM......................................................................................................74FIGURE 15 A WELLPOINT PUMP USED IN SUNWAY PYRAMID II PROJECT.............................................................75FIGURE 16 SELF-JETTING WELLPOINT...........................................................................................................76FIGURE 17 JET-EDUCTOR WELLPOINT SYSTEM FOR DEWATERING A SHAFT............................................................79FIGURE 18 SAND DRAINS FOR DEWATERING A SLOPE.......................................................................................80FIGURE 19 INSTALLATION OF MANDRELS USING DRAIN STITCHER.......................................................................80FIGURE 20 ELECTRO-OSMOSIS WELLPOINT SYSTEM FOR STABILIZING AN EXCAVATION SLOPE...................................81FIGURE 21 INSTALLATION OF ELECTRO-OSMOSIS IN A DEWATERING SITE.............................................................82FIGURE 22 GROUT CURTAIN OR CUTOFF TRENCH AROUND AN EXCAVATION.........................................................83FIGURE 23 DETAIL OF SLURRY TRENCH.........................................................................................................85FIGURE 24 STEEL SHEETING TO TOP OF ROCK. A BOULDER ABOVE THE ROCK CAN AGGRAVATE THE SITUATION............86FIGURE 25 STEEL SHEETING IN SUNWAY PYRAMID II PROJECT TO CONTROL SEEPAGE AND STABILIZING THE SLOPE.......87FIGURE 26 EXCAVATION SUPPORTED BY A GRAVITY FREEZEWALL.......................................................................88FIGURE 27 TYPICAL SCENARIO OF FREEZE PIPE SPACING AND INDICATION WHICH CAN BE CONNECTED TO A PORTABLE

REFRIGERATION PLANT, OR LIQUID NITROGEN TANKER.............................................................................88FIGURE 28 CIRCULAR EXCAVATION SUPPORTED BY A FREEZEWALL. (A) PLAN. (B) SECTION.....................................89FIGURE 29 A DEEP EXCAVATION SUPPORTED BY FREEZE WALL...........................................................................89FIGURE 30 CSP AT THE SOHO PROJECT......................................................................................................96FIGURE 31 RE-BAR OF CSP........................................................................................................................97FIGURE 32 CSP SIDE USE MORTAR..............................................................................................................97FIGURE 33 LAYOUT OF CSP.......................................................................................................................98FIGURE 34 CANVAS METHOD.....................................................................................................................99FIGURE 35 CANVAS TO THE SLOPE..............................................................................................................99FIGURE 36 RETAINING WALL....................................................................................................................100FIGURE 37 WATER PUMP........................................................................................................................101FIGURE 38 WATER FLOW........................................................................................................................101FIGURE 39 PONDING AT SITE....................................................................................................................102FIGURE 40 TEMPORARY DRAINAGE............................................................................................................102FIGURE 41 TEMPORARY DRAINAGE............................................................................................................103

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FIGURE 42 ACCESS ROUTE.......................................................................................................................104FIGURE 43 BARIER GATE..........................................................................................................................105FIGURE 44 WASH PIT.............................................................................................................................106FIGURE 45 HOUSEKEEPING......................................................................................................................106FIGURE 46 HOARDING............................................................................................................................107FIGURE 47 WASH PIT.............................................................................................................................108FIGURE 48 GATE BARIER.........................................................................................................................108FIGURE 49 PROJECT SIGNAGE...................................................................................................................109FIGURE 50 POINT OF STTLEMENT CONTROL.................................................................................................110FIGURE 51 SETTLEMENT MARKER RECORDS................................................................................................111

2 PROJECT

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2.1 PROJECT DESCRIPTION

PROJECT SUBANG SOHOCADANGAN PEMBANGUNAN FASA B YANG MENGANDUNGI 1 BLOK SOHO 23 TINGKAT (488 UNIT) TERMASUK 5 TINGKAT TEMPAT LETAK KERETA DI ATAS LOT 20926 (P.T. 11921) H.S (D) 48924, MUKIM DAMANSARA, DAERAH PETALING, SELANGOR DARUL EHSAN UNTUK TETUAN SENDI BANGGA DEVELOPMENT SDN. BHD.

CLIENT SENDI BANGGA DEVELOPMENT SDN. BHD(whole subsidiary by Titijaya Group)Lot 3-10, 3rd Floor,First Tower, Jalan Meru,41050 Klang, Selangor.Tel : 03-3341 1111 Fax : 03-3341 2992

ARCHITECT ARKITEK KDI SDN. BHD1st Floor,No 87 & 89, Jalan Ipoh51200 Kuala Lumpur.Tel : 03-4045 3193 Fax : 03-4045 3187

STRUCTURAL ENGINEER

CSI CONSULTANT No. 25-7, Jalan USJ 9/5Q,Subang Business Centre,47620 UEP Subang Jaya, SelangorTel : 03-8023 6312 Fax : 03-8023 6316

CIVIL ENGINEER PETAREKA PERUNDING (M) SDN. BHDNo.5, jalan 11/62 A,Bandar Seri Menjalara,52200 Kuala Lumpur, MalaysiaTel : 03-6272 6878 Fax : 03-6272 8878

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M & E FADHULLAH & ASSOCIATES CONSULTING No. 4A&4B, Jalan BPU 9,14th Mile, Jalan Puchong,Bandar Puchong Utama, 47100 Selangor.Tel : 03-5891 1535/1536 Fax : 03-5891 1538

LANDSCAPE ARCHITECT

ECO HABITAT 3-3, Jalan Damar SD 15/1, Bandar Sri Damansara,52200 Kuala Lumpur.Tel : 03-6277 0083 Fax : 03-6277 1646

QUANTITY SURVEYOR

DL QS CONSULTNo. 11-2 (2nd Floor), Jalan USJ 10/1ETaipan Business Centre,47620 UEP Subang Jaya, Selangor.Tel : 03-5638 8267 Fax : 03-5638 0268

CONTRACTOR G-PILE SISTEM SDN. BHDLot 1.01 Level 1, KPMG Tower,No. 8 First Avenue, Bandar Utama,47800 Petaling Jaya, Selangor.Tel : 03-7710 6477/8477 Fax : 03-7710 5477

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Figure 2 Site Plan of SOHO Project

Figure 3 SITE LAYOUT - SOHO Project

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G-PILE SISTEM SDN BHD

SENIOR MANAGERDING CHENG HUAT

SR. CONTRACTS MANAGERSHIRLEY SIM

TECHNICAL MANAGERIR. WARREN CHOO

DIRECTORLING HUA EE

PROJECT QSSHARON TAN

ASST. PROJECT MANAGERLOH MUN HONG

PLANNING MANAGERYAU KIM WEI

SURVEYORLEE FONG YONG

SUPERVISORRIDZUWAN/ZULKIFLI

SAFETY OFFICERAZAHARI

Base in HQ

Base on Site


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2.2 SITE ORGANISATION CHART

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2.3 INTRODUCTION

The subtopics that we get for our case study about Planning and

Controlling of Earthwork Operation Multi-Storey Building; for the assigment’s

subject in Construction Technology’s (BLD 410).

Practicality that can be seen and understand, the planning and

controlling by the contractor when get the project. Planning operation is

include about cost estimated, method/sequence of work, project planning and

also the machineries used during the earthwork operations. For the

controlling, included about slope, dewatering system, trafic control, safety

control, settlement control, and documantation control.

Based on this topic, we are together chosen one of the private

companies to do this research. The company is Sendi Bangga

Development Sdn. Bhd this company is a wholly owned subsidiary of Titi

Jaya Holding Sdn. Bhd.

These construction works were done and responsibility by Sendi

Bangga Development Sdn. Bhd as a developer of “SUBANG SOHO;

Cadangan Pembangunan Fasa B Yang Mengandungi 1 Blok Soho 23

Tingkat (488 Unit) Termasuk 5 Tingkat Tempat Letak Kereta Di Atas Lot

20926 (P.T. 11921) H.S (D) 48924, Mukim Damansara, Daerah Petaling,

Selangor Darul Ehsan Untuk Tetuan Sendi Bangga Development Sdn.

Bhd.”; 2.7 million project (earthwork operation).

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3 PLANNING OF EARTHWORK OPERATION MULTI-STOREY PROJECT

3.1 INTRODUCTION

Earthwork operations involve the excavation, transportation and placement or

disposal of materials. They typically involve repetitive work cycles, expensive

fleets and large volumes of work. Consequently, even small improvements in

planning result in substantial cost and time savings. It is for these reasons

that earthwork operations improvement has been the focus of so many

studies. The work is performed outdoors under conditions that are highly

variable and that affect the performance of the different pieces of equipment.

Factors that affect performance include weather (i.e., trucks cannot travel as

fast on wet, muddy haul roads), haul road maintenance (i.e., a well-

maintained road reduces rolling resistance), operator experience, ground

conditions, load and dump area layouts, and the material being excavated.

Earthwork operations are actively managed with many decisions made

dynamically on site in reaction to the evolving status. A truck, for example,

may be routed to an alternate load area if the loading unit at the main area is

under maintenance or if several other trucks are queuing for it. Sometimes

the strategies that guide these dynamic decisions are quite complex but

necessary. They can also significantly impact the performance of the

operation. The probabilistic nature of the work and the dynamics of earthwork

operations make them difficult to plan. They are typically planned using

simplified back-of-the envelope calculations, but mainly relying on the

experience and insights of the planner. Discrete-event simulation is the only

earthwork analysis method that can explicitly incorporate the detailed but

significant aspects (e.g., equipment characteristics, haul road conditions,

load and dump area configuration, and dynamic context-based decisions) of

an operation.

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3.2 DESIGN STAGE

3.2.1 SCOPE

This part is sets out the recommendations for the carrying out of earthworks

or preparation or foundations of multi-storey project at SUBANG SOHO, or

both, including:

a) The excavation and filling of land to form new contours;

b) The assessment and protection of slope stability;

c) The suitability of both natural and filled ground for the founding of

roads, buildings,

d) Services and other works;

e) The control of erosion and siltation’s during and after earthworks.

Because of the wide range of soil types, physical conditions and

environmental factors which apply in different areas it is not often possible to

lay down precise requirements which will be subject in particular instances to

the judgement of the Engineer, owner's representative or soils engineer.

(John, 2007)

3.2.2 GENERAL

Choice of final landform is dependent on many factors which may be specific

to the subdivision or development. These include:

a) Relation with surrounding landscape;

b) Size;

c) Roading pattern;

d) Preservation of natural features;

e) Stability;

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f) Damage by flood or other natural occurrences such as erosion by sea,

river, or surface storm water run-off.

Provision is made in this standard for certification of suitability of land for

subdivision and development to meet the requirements of this Standard. This

requirement is independent of the requirements under the Building Act 1991.

Reference is made to the desirability of using local material which may

provide a satisfactory foundation in particular circumstances.

3.2.3 TECHNICAL RESPONSIBILITIES

Where any land development or subdivision involves the carrying out of bulk

earthworks, the assessment of slope stability, or the detailed evaluation of

the suitability of natural ground for the foundations of buildings, roads,

services or other works, then a soil engineer should be appointed by the

developer to carry out the following instructions:

a) Prior to detailed planning of any development to undertake a site

inspection and such investigations of subsurface conditions as may be

required.

b) Before work commences to review the drawings and specifications

defining the earthworks proposed, and submit a written report to the

Engineer on foundation and stability aspects and any proposed

departures from this Code and associated standards.

c) Before work commences and during construction to determine the

extent of further specialist soils engineering services required

(including investigation and geological work).

d) Before and during construction to determine the methods and

frequency of construction control tests to be carried out, determine the

reliability of the testing, and to evaluate the significance to test results

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and field inspection reports in assessing the quality of the finished

work.

e) During construction to provide regular inspection (while a daily visit

might be regarded as reasonable on earthwork construction on minor

projects, inspection on a nearly full time basis is often necessary).

f) On completion to submit a written report to the Engineer attesting to

the compliance of the earthworks with the specifications, and as to the

suitability of the subdivision for building construction.

The owner's representative may act as the soils engineer if he possesses

suitable qualifications and experience.

The construction control testing should be carried out by a competent person,

or, preferably, under the control of the soils engineer, and with Testing

Laboratory Registration Council (Telarc) registration in all relevant tests.

(John, 2007)

3.2.4 SITE INVESTIGATIONS

3.2.4.1 PRELIMINARY SITE EVALUATION

Prior to any detailed planning or design, the owner's representative or soils

engineer, as applicable, should undertake a preliminary evaluation of the

general nature and character of the site in sufficient detail to determine the

likely requirements for earthworks or the need for further investigations into

the suitability of foundation conditions, or both, and the stability of the natural

ground. The preliminary evaluations should be carried out in the context of

the total surrounds of the site, and should not be influenced by details of land

tenure, territorial or other boundary considerations. In simple cases a visual

appraisal may be sufficient, but in other cases depending on the nature of the

project, its locality, the scale of development proposed and individual site

characteristics, particular attention may need to be given to the following

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matters which should normally be considered prior to preparing a proposal

for subdivision or development.

a) Drainage. It is important to identify the existing natural drainage

pattern of any area and to locate the natural springs or seepage.

b) Where any natural drainage paths are interfered with or altered by

earthworks then appropriate measures should be taken to ensure that

sufficient adequate alternative drainage facilities are provided.

c) Slope Stability. Some natural slopes exist in a state of only marginal

stability and relatively minor works such as trenching, excavation for

road or building platforms, removal of scrub and vegetation, or the

erection of buildings, can lead to failure. Signs of instability include

cracked or hummocky surfaces, crescent shaped depressions,

crooked fences, trees or power poles leaning uphill or downhill,

uneven surfaces, swamps or wet ground in elevated positions, plants

such as rushes growing on a slope and water seeping from the

ground.

d) Foundation Stability. A study of the general topography of the site and

its surroundings may indicate areas which have previously been built

up as a result of natural ground movement or by the deliberate placing

of fill material. Unless such fill has been placed and compacted under

proper control, long term differential settlement could occur causing

damage to superimposed structures, roads, services or other

subdivision works.

Note: The District contains a number of areas where 'tomos' have developed.

These may affect the suitability of a site for development and consequently

these will require identification and addressing as part of any development

proposal.

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3.2.4.2 SPECIALIST SERVICES

Where a soils engineer has been appointed as recommended in section Technical Responsibilities then prior to or at the time of submission of an application or subdivision or development he should submit to Council a written report setting out the particulars of any investigations carried out including details of contours, natural features and modifications proposed thereto; and shall furnish to Council a statement of professional opinion as to the suitability of the land for subdivision with details of any special conditions that should be imposed.

3.2.5 PLANNING AND DESIGN

3.2.5.1 LANDFORM

The final choice of landform should represent the most desirable compromise

between the factors referred to above and the preservation of natural

features and the natural quality of the landscape including the retention of

natural watercourses.

The choice of suitable landform is dependent on many factors which may be

specific to a particular site. In general, unnecessary earthworks should be

avoided but considerations which may justify the carrying out of earthworks

include:

a) The minimisation of the possibility of damage to property occurring

through ground movement in the form of slips, subsidence, creep,

erosion of settlement.

b) The minimisation of the possibility of damage to property occurring

through flooding, or surface water run-off.

c) The development of a more desirable roading pattern with improved

accessibility to and within the site and the creation of a better sense of

orientation and identity of the area as a whole.

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d) The efficiency of overall land utilisation including the quality of

individual sites and amenity areas around buildings, the economics of

providing engineering services, and the standard of roading and on-

site vehicular access.

e) The need to create suitably graded areas for playing fields and other

community facilities.

f) The enhancement of the general environmental character of the area

by softening the landscape or by artificially creating or emphasizing

landforms of visual significance particularly on flat sites or on areas

devoid of landscape features, or preservation of some specifically

significant feature.

3.2.5.2 SOIL INVESTIGATIONS

Where appropriate the general nature and shape of the ground should be

studied and particular note taken of:

a) The geological nature and distribution of soils and rock;

b) Existing and proposed drainage conditions and the likely effects on

ground water;

c) Previous history of ground movements in similar soils in the area; and

d) Performance of comparable cuts and fills (if any) in adjacent areas.

Soil data should be obtained for areas which:

a) Are intended to form in situ bases for fills;

b) Are intended to yield material for construction of fills; and

c) Are intended to be exposed as permanent batters.

Sufficient borings, probing or open cuts should be made:

a) Classify the soil strata by field and visual methods;

b) Evaluate the likely extent and variation in depths of the principal soil

types, and

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c) Relating subsequent soil test properties to relevant strata over the site.

The test data appropriate in different areas shall be determined by the soils

engineer.

3.2.5.3 STABILITY CRITERIA

Settlement. The most important factor in ensuring satisfactory performance of

stable fills is the limiting of post-construction differential settlements. The

design and construction of fills should be such that these settlements are

kept within acceptable limits.

The weight of residential buildings of one-storey and two-storey construction

not requiring specific design, is unlikely to produce significant settlement of fill

constructed in accordance with this Code. Local filling placed close to a

house during or after construction, for example, for a patio, will produce much

larger stress increases which may induce differential settlement of the house.

Bearing Capacity. The strength of the ground resisting general shear failure

(and resulting gross deformation) under the footings of a house is a local

phenomenon distinct from settlement. Fill constructed to minimize settlement

in accordance with this Code will have adequate shear strength.

It should be noted, however, that despite careful construction there may be

localised soft areas in the upper layers of fill within the zone of influence of

small foundations. Should the routine foundations inspection by the building

or the local authority during construction suggest, or should the Engineer

suspect, that localised soft areas are present, then

tests should be made to determine the required treatment of the fill material,

or of the foundations. These tests should extend to a depth as agreed with

the Group Manager Asset Management and may include shear strength

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tests, field load tests or dynamic penetrometer tests or other recognised soil

strength tests.

Note: The developer should refer to the Natural Hazards Register contained

in Volume 4 of the District Plan.

The adequacy of subgrade compaction and proposed pavement depth for

road works shall be confirmed by tests on the finished subgrade. This

requirement is compulsory for new roads to be vested in Council.

Shrinkage and Expansion. Because some clay soils are likely to undergo

shrinkage and swelling when subjected to seasonal changes in water

content, special examination of welling and shrinkage characteristics should

be made in the case of highly plastic soils.

Where applicable, the need for a foundation depth or design to minimise

these effects, particularly for continuous brittle walls, should be noted in the

completion report and statement of the soils engineer.

Slope Stability. In most cases, it is unnecessary or impracticable to measure

quantitatively the factor of safety of a slope against shear failure. Maximum

slopes of cuts and fills may be determined by the soils engineer from

experience and from observation of slopes in the vicinity which have a long-

standing history of stability, are of similar height to the proposed slope and

are of apparently similar geological formation.

Where necessary or a precedent is not available, a special soils engineer

investigation should be carried out by the soils engineer to determine

acceptable limits to cut and fill slopes. In assessing slope stability account

should be taken of possible future changes in ground water level or other

conditions. Where a fill may be required to act under extreme conditions as a

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detention dam, investigation should include the ability of the fill to act as a

detention dam and upstream effect of the fill.

3.2.5.4 QUALITY OF FILLING MATERIALThe majority of soils, other than organic material, are potentially suitable for

fillings under controlled conditions. However, the Group Manager Asset

Management retains the right to disallow the use of unsuitable fill material.

3.2.5.5 COMPACTION STANDARDS FOR FILL MATERIALThe standard of compaction should be measured in terms of one of the

following:

a) Relative Compaction. That is, the ratio of the field dry density of fill to

the maximum (laboratory) dry density expressed as a percentage.

Unless otherwise required by the soils engineer, fill should be

compacted to at least 95% relative compaction, in terms of the

standard method of compaction.

b) Air Voids and Shear Strength. Used for cohesive soils, where specific

test methods and criteria should be determined by the soils engineer,

who may, for example, require air voids to be less than 10% and shear

strength to be not less than 50 kPa on completion of construction.

c) Relative Density. That is, the field dry density expressed in terms of

maximum minimum densities established by laboratory test (used for

cohesionless soils). The specific minimum value should be determined

by the soils engineer who may, for example, require a minimum

relative density of 80%.

d) Field Relative Compaction (Field Proctor Test). This is the ratio of the

density of the compacted fill material at its in situ moisture content,

relative to the density of the same material at the same moisture

content after standard compaction (Proctor compaction). (This method

gives a quick determination of the actual field compactive effort being

applied, relative to Proctor compaction, without need for drying in the

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testing procedure, and this may be adequate control provided the

material is close to optimum moisture content.)

3.2.5.6 EROSION CONTROLSubdivision or development should be carried out in such a manner as to

restrict soil erosion to acceptable levels. This can be achieved by adopting

sound design and construction procedures.

Diversions of natural water and the discharge of water containing silt arising

from subdivision or development works are subject to either a land use, water

or discharge permit in terms of the Resource Management Act 1991. Where

the Regional Council has issued a general authorisation, that is - for the

diversion or discharge of water or water containing sediment associated with

subdivision or development, the subdividing owner's representative shall

comply with the conditions of such authorisation including notification to the

Regional Council if required. Where water is to be diverted from one

catchment to another, the effect on that catchment should be investigated,

and where necessary approvals shall be obtained from the respective

authorities or owners, or both.

Without prejudice to the conditions of any Resource Consent the following

practices should be adopted in the planning and design of land subdivision or

development projects involving earthworks:

a) Large projects should be programmed for construction in selfcontained

stages which can be largely completed within one earthworks season.

Where possible, the upper part of a catchment should be developed

first.

b) Where possible, the permanent storm-water system should be

designed so it can be constructed at an early stage in the project and

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be used to collect run-off from the site during construction in

conjunction with silt control measures.

c) The specifications should require the use of construction procedures

which minimise concentration of run-off and excessive velocities,

which could otherwise result in erosion.

d) Silt retention ponds should be constructed and maintained in all

earthworks projects where they are feasible and necessary.

e) Graded "V" drains (also called contour drains) should be used to divert

run-off water from non-construction areas past site-works or to divert

run-off from exposed areas into silt retention ponds and reduce

overland flow distances on bar surfaces. Such drains should have a

maximum slope of 1 in 30 and a maximum design velocity of flow

2m/s.

f) Cut and fill areas should be re-topsoiled and sown as soon as possible

after earthworks and drainage works.

g) The batter faces of cuts and fills should be protected as soon as

possible after construction by grassing, hydroseeding, tree planting, or

other suitable surfacing.

3.2.5.7 PROVISION FOR PERMANENT SERVICES

Where settlement is expected to occur, all service pipes installed within or

under earth filling shall be designed and constructed to ensure adequate

capacity, strength and water-tightness to withstand the loads due to

settlement and to prevent leakage into the fill.

Where surface water could cause erosion of batters or internal instability

through soakage in the soil, open interceptor drains should be constructed in

permanent materials, and benches in batter faces should be sloped back and

graded longitudinally to reduce spillage of storm-water over the batter. Water

from storm water systems should be prevented from flowing into a fill or into

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natural ground near the toe or sides of a fill and no storm-water soak pits

should be constructed in a fill whereby the stability of the fill might be

impaired.

All drains required permanently to protect the stability of fillings or to prevent

flooding and erosion should be clearly identified as such on "as built"

drawings.

3.2.6 FINAL DOCUMENTATION

3.2.6.1 "AS-BUILT" DRAWINGS

On completion of the earthworks an "as-built" plan should be prepared

showing the extent and depth of fill in the form of lines joining all points of

equal depth of fill at vertical intervals of for example, 500mm or 1m as

appropriate. The "as-built" plans should also record the position, type and

size of all subsoil drains, and their outlets. The plans should also show areas

of filling of low density and any fill areas which the soils engineer considers

do not comply with this Standard.

3.2.6.2 SOILS ENGINEER'S REPORT

On completion of construction, the soils engineer should furnish for the

engineer a report describing the extent of the inspection and the results of

testing together with a statement of professional opinion as to the compliance

of the filled ground to the specification, the suitability of filled ground for

specified types of building construction, and where applicable, the suitability

of original ground for specified types of building construction.

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3.2.7 PROTECTION OF THE WORKS

The Contractor's responsibility for care of the Works shall include the

protection of earthworks. The Contractor requires an Environment Protection

Agreement or an Authorisation with the Environment Management Authority

for all construction or building activities on a site more than 0.3 hectare and

must be obtained prior to commencement of work. No extensions of time will

be granted or allowed relative to any delay with obtaining of the necessary

Agreement and other approvals unless it is shown to the satisfaction of the

Superintendent that all necessary steps have been taken on time by the

Contractor.

Where the Contract documents include a suggested Sediment and Erosion

Control Concept Plan, the Contractor is still responsible for the adequacy of

those arrangements. The Contractor may choose to adopt those concept

arrangements as the basis for applying for approval, or alternatively the

Contractor may propose his own measures as the basis for approval. Prior to

commencement of work the Contractor must provide two copies of the

Sediment and Erosion control measures plan to Environment ACT – Water

Unit for approval. Two copies of the endorsed as approved drawing(s) shall

be provided to the Superintendent.

In addition to those erosion and sediment control measures suggested in the

Contract documents and the Sediment and Erosion Control Measures Plan

the Contractor shall generally plan and manage the works to minimise

erosion on the site. It is expected that control measures may include the

following

1) Control over surface run-off by:

a. construction of interception drains to divert run-off from undisturbed

areas around the works area

b. installation of temporary drains

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c. early stabilisation of floodways

d. use of straw bales, silt fences, swales, contour ploughing or rip dozer

cleat impressions, spreader banks.

2) Limit movement of vehicles and equipment to:

a. a single approved stabilised construction entrance

b. prepared parking areas by the construction of temporary fencing.

3) Minimise the area exposed by:

a. staging of clearing operations

b. progressive stabilisation of the works as completed

c. provision of temporary grassing

d. contour ploughing to disturbed areas.

4) Construction of sediment control measures such as:

a. sediment retention ponds,

b. sediment basins

c. sediment traps (various types)

d. silt fences

e. buffer zones

Refer to "Erosion and Sediment Control During Land Development –

Environment ACT" for details. Where the approved control measures include

sediment retention ponds, and notwithstanding the requirements arising

elsewhere in the Contract documents or from Environment ACT and, then:

a) The ponds shall be kept empty of water for the longest practical

duration. During periods of high in-flow of water and sediment, causing

overtopping over the pond spillway, the Contractor shall regularly test

the quality of the waters being released and treat the water with

chemicals as and when necessary in order to achieve a water quality

for the released water complying with the above legislation and licence

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and to maintain sufficient residual gypsum or an acceptable chemical

in solution to sustain treatment of subsequent inflow. When there is an

inflow which is insufficient to cause overtopping over the pond

spillway, then the water is to be treated as necessary and emptied

within three days of the inflow occurring.

b) The Contractor shall remove and dispose of accumulations of

materials from the ponds as often as is necessary to maintain their

interception capacity to at least ninety percent (90%) of the design

volume of the pond.

c) The Contractor shall develop and implement procedures and a

programme and provide all necessary equipment, materials and

labour to carry out water testing; calibration test; dosing with

chemicals; and the controlled release of waters so as to comply with

the requirements of the legislation and licence. The testing procedure

shall be developed using a turbidity meter which shall be calibrated

with a series of test results on water samples with a range of Non-

Filterable Residue levels. The Contractor shall arrange laboratory

tests for Non-Filterable Residue and obtain advice on dosage rates

ensuring that the pH is within acceptable limits, and then if possible

develop a simple field correlation technique for assessing the

suitability of the water for release. Dosing can be carried out using an

acceptable chemical such as gypsum, using a simple slurry mixing

and spreading technique designed to achieve acceptable water

quality. Gypsum is preferred because it does not change the pH and

unless there are problems in effectiveness it shall be the chemical

used. Unless specified elsewhere within the Contract, or directed

otherwise by the Superintendent, then the sediment and erosion

quality control measures will be provided, operated and managed,

maintained or replaced as necessary for the period of the contract,

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including the consolidation period and/or the Defects Liability Period

as required to fulfil the requirements of the Pollution Control Act.

3.2.7.1 PROTECTION OF EARTHWORKS

Protect earthworks and in particular road formations from the effects of

erosion and deposition. Grade earthworks and particularly subgrades to drain

at all stages without ponding. Where run-off must cross the formation, ensure

that the stream is a broad sheet flow which crosses roughly at right angles to

the alignment and minimises the likelihood of subgrade softening. When rain

is likely or when work is not proposed to continue in a working area on the

following day, precautions shall be taken to minimise ingress of any excess

water into earthworks material. Ripped material remaining in cuttings and

material placed on embankments shall be sealed off by adequate compaction

to provide a smooth tight surface. Should insitu or stockpiled material

become over wet as a result of the Contractor not providing adequate

protection of earthworks, the Contractor shall be responsible for replacing

and/or drying out the material and for any consequent delays to the

operations.

3.2.7.2 PROTECTION OF COMPLETED EARTHWORKS

In areas where earthworks, including open drains, have been completed and

no further treatment is specified other than topsoiling and grassing or

hydroseeding, then the topsoiling and seeding shall be carried out as

specified at the earliest practicable date. Areas of exposed completed

earthworks shall, if directed, be stabilised using temporary grassing, within 28

days of formation.

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3.2.8 CLEARING AND GRUBBING

3.2.8.1 GENERAL

Unless otherwise specified, remove all vegetation, logs, stumps, boulders,

roots, scrub, debris and dumped material and items within the limits of

clearing. Demolish and dispose of any minor man-made structures (such as

fences and livestock yards), all rubbish and other materials that are

unsuitable for use in the Works. Grass and topsoil shall not be removed as

part of this initial clearing. In advance of clearing and grubbing operations,

effective erosion and sedimentation control measures shall be implemented

in accordance with this Specification.

All trees and stumps, on or within the limits of clearing, unable to be felled

and removed by the clearing methods used by the Contractor shall be

removed by grubbing. Grub out stumps and roots over 75mm diameter to a

minimum depth of 0.5m below the natural surface or 1.5m below the finished

surface level, whichever is the lower. Backfill grub holes with suitable spoil

from excavations compacted in layers to the density of the surrounding

undisturbed soil.

The Contractor shall take all measures to prevent damage to existing

underground and overhead utility services. Every precaution shall be taken to

prevent timber from falling on private property and the Contractor shall

dispose of any timber so fallen or produce the written consent of the owner to

its remaining there. The cost of disposal of such fallen timber shall be borne

by the Contractor. Prior to entering private property, the Contractor shall

obtain consent from the Superintendent and the property owner. Damage of

any kind, including damage to trees and fencing occurring during clearing

operations shall be made good by the Contractor. The cost of repair of such

damage shall be borne by the Contractor.

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Limits of clearing are defined as lines one metre outside the intersections of

excavation or embankment slopes with the natural surface or the outside

limits of slope rounding together with any other limits detailed. For services

trenches outside the general limits of clearing, limit of clearing is defined as

trench width plus one (1) metre either side of the trench. The Contractor shall

ensure that only the absolute minimum necessary for construction is cleared.

3.2.9 Disposal of Material

Unless otherwise specified, all materials cleared and grubbed in accordance

with this Specification shall become the property of the Contractor and shall

be removed from the site and legally disposed of. Unless otherwise specified

elsewhere, disposal of timber and other combustible materials by burning

shall not be permitted. Where permitted, the Contractor shall comply with all

Statutory requirements applicable to burning off, and any such burning off

shall be carried out in such a manner that no damage is done to any trees

outside the limits of clearing. Smoke resulting from such burning off shall not

cause a traffic hazard or a nuisance to adjacent landholders.

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3.3 PLANNING STAGE

3.3.1 COST ESTIMATED

Construction cost estimating is demanding work, no matter what type of

construction is involved. But, estimating earthwork is the hardest of all. That

is because, excavation has more variables and unknowns; don’t know what’s

down there until start digging. Also have to rely on information from many

sources – some of which may not be accurate.

That’s why every earthwork estimator needs special skills:

a) The ability to read plans and specifications

b) An understanding of surveying and engineering practice

c) A facility with mathematical calculations

d) The ability to anticipate environmental and legal issues

e) An abundance of good common sense

In the past, many smaller dirt jobs were bid as a lump sum rather than by the

cubic yard. Dirt contractors based their bid on guesses – what equipment

was needed and how long should it takes? They didn’t bother estimating soil

quantities. Making estimates this way overcome one problem; most

excavation contractors didn’t know how to estimated soil and rock quantities.

Fuel and labour costs are too high now. And the competition is too intense.

There’s too much risk in “seat-of-the-pants” guesses. A few mistakes, a

couple of surprises and to be looking for some other type of work. Only the

best survive for long in this business. Most of the survivors know how to

make accurate bids by the cubic yard. Fortunately, making good quantity

estimates isn’t too hard if mastered a few simple skills.

(Burch, 2007)

3.3.1.1 THE SITE VISITA site visit is an important part of every earthwork estimate. If skip this

important step, the estimate is just a guess.

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1) Review the plans first

Before go to the site, take time to review the plans completely. Make

an itemized list of any special problems or unusual requirements; pick

up from plans and specifications. Take that list and check each item

while in the field.

The amount of information provided on the plans will determine how

much work have to do to prepare for the site visit. If have a complete

set of plans and specifications, it’s easy to list the questions that need

answers.

When go into the field on a site visit take along two lists. The first is a

list of specific questions based on the current plans and specifications.

The second is standard checklist for site visit. Every estimator needs a

checklist to work from. Maybe overlooked something once; put it on

the list.

2) Make the visit productive

The visit to the site can make a significant difference in the amount of

the bid – and size of contractor’s profit. Analyze the job site anticipate

problems that might interrupt work scheduling, situations that require

specialized equipment, or shortcuts to speed the work along. It takes

knowledge and experience to make the site visit productive. Most of

the know-how comes from experience on past projects. Also can use

common sense to come up with a more cost-effective way to d the job.

Use the site visit to plan the construction scheduling and to anticipate

equipment and labour requirements. The actual conditions of the site

will dictate the type of equipment needed and the way the work is

done.

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3) Accessibility

First, consider the physical location of the site. How remote is it? What

roads or streets lead to the site? Are the any one-way streets leading

to the site? All this will have a direct bearing on the work. If have to

bring dirt in or take it out, consider the distance to the borrow or dump

site. In fact, recommend driving the route several times, using different

roads to find the shortest and best route. If the surrounding streets

carry heavy traffic, it will slow down the movement of equipment to

and from the work site. Will traffic problems require the use of one or

more flagmen? Look for any other safety-related problems that might

require additional manpower. Is the site near any homes or business?

Is there a noise ordinance and its enforced? Take complete notes

during the site visit on any variable that will affect the profit and works.

4) Degree of job difficulty

Are there any steep slopes that would require unusual equipment? Is

the area open, or are these obstructions like buildings, trees,

sidewalks, or utility lines in the way? Any of these will slow down the

production. If specialized equipment is needed, will it e available in the

area or will have to bring it in from a distance. This is a good time to

decide what size and type of earthmoving equipment to use. Consider

whether there’s enough room for the equipment to turn and move

economically. When making the decision, consider the ground

conditions, traction, and the distances and directions have to move.

Remember, the track machines have a slower working speed.

5) Surface condition

Drainage problems, steep slopes, dense vegetation, and sharp or

large rocks scattered on the surface will all hamper production.

Drainage is one of the biggest problems. Provide the drainage

channels to reroute water during construction. But can’t divert water

onto streets or roads.

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6) Subsurface conditions

Even have the soil tests on the site, the actual conditions of the soil

below the surface are really anybody’s guess. Water running on the

surface indicates underground water seeps. If the work limits are

below the local water table, have to pump water from trenches and the

excavation portions of the job.

7) Utilities

Try to determine if utility lines are shown in the correct location on the

plans. Utility lines sometimes aren’t where the plans show them. A

variation of just a few feet can make a big difference in time when

working in a confined area. If there exist storm or sewer lines, check

the manholes for conditions, material and depth to flow line. Also

check for size, direction and number of inlets and outlets in the

manhole. Check for overhead wires that would be in the way of

working equipment. Will the temporary electric or phone connection

are needed.

8) Project size

Consider whether building materials and equipment can be stored on

the job site without interfering with the work.

9) Local needs

Locate local suppliers of fuel, repairs, parts and any other operations

needs. Find out the policy on credit or payments. Get an agreement in

writing if possible. Plan to use local workers, expected wages for the

labour.

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10)Traffic control

If the project will need traffic control, check with the local authorities to

see what they require. Most of them spell out traffic control

requirements very clearly. There are exact standards for barricades,

delineators, flashing light and other safety precaution.

11)Security

The job site is isolated or in an area with high crime rate, may want to

hire a security company. Vandalism to equipment or material, theft,

and destruction of completed work can be a major financial loss. Most

of it won’t be covered by the insurance. That makes it a cost of doing

business. Also consider public safety. Job will probably drawn

sidewalk superintendents. Everyone loves watching heavy equipment

at work. So, need to protective fencing around the area, to keep

people out of danger.

12)Existing and imported soil

Look at the soil itself, both the existing soil any soil that must be

trucked in. Checked the compaction requirements. The more

compaction needed, the more time required for rollers.

3.3.1.2 THE BULK AND SHRINK FACTORSUsing the bulk and shrink factors to make the estimated more accurate.

That’s because a given quantity of soil has no constant volume. Add moisture

and the soil bulks, expanding in volume. Soil volume also increases when it’s

loosened or disturbed by excavation. Conversely, the soil volume shrinks or

contracts when apply pressure to compact the fill. Actual bulk and shrink

factors consider the combined effect of:

a) Moisture content

b) Density (compact versus loose)

c) Soil type

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The volume of soil in the original ground will change when the soil is

excavated and loosened, or when it is filled and compacted. The volume of

soil should be adjusted so as to compute the volume to be excavated, hauled

and embankment on a common basis.

1) Bulking Factors

Bulking factors (L) =Volume of loosened soil after excavation

Volume in the ground before excavation

Soils and rocks usually swell when they are excavated; thus 1m3 of

material in the ground will occupy more than 1m3 in the transporting

vehicle. This must be allowed for in assessing the amount of transport

required and their number of trips and therefore the cost of

transporting materials.

2) Shrinkage Factors

Shrinkage factors (L) =Volume after compaction

Volume in the ground before excavation

Excavated soils except some firm granular materials usually shrink

when they are compacted. Necessary to plan how much volume of

soils is to be hauled to which parts of embankments; to estimate how

much volume of soil in the ground shall be cut and borrowed to form

an embankment.

Both factors are assisting to measure the output productivity before run the

construction. It does also can calculate the number of excavator, Lorries and

labour needed to carry out soil from the site or embankment the soil to the

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site. There are also help to preparing the budget and time duration for

earthwork operations.

Bulking and shrinkage factor of various soil

Type of soil Bulking factor (L)

Shrinkage factor (C)

Rocksa) Hard rocksb) Loose rocksc) Boulders/cobbles

1.65 – 2.001.30 – 1.701.10 – 1.20

1.30 – 1.501.00 – 1.300.95 – 1.05

Gravelly Soilsa) Gravelsb) Gravelly soilsc) Solidified gravelly soil

1.10 – 1.201.10 – 1.301.25 – 1.45

0.85 – 1.050.85 – 1.001.10 – 1.30

Sandsa) Sandyb) Sandy & cobble

1.10 – 1.201.15 – 1.20

0.85 – 0.950.90 – 1.00

Common soila) Sandy soilsb) Sandy soils with cobbles

1.20 – 1.301.40 – 1.45

0.85 – 0.950.90 – 1.00

Cohesive soila) Cohesive soilsb) Cohesive soil with

gravelsc) Cohesive soil with

cobbles

1.20 – 1.451.30 – 1.451.40 – 1.45

0.85 – 0.950.90 – 1.000.90 – 1.00

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3.3.1.3 CALCULATION

Figure 4 The soil that will excavate. (35, 000m3)

This site will be excavate soil from reduce level 21.00 to 15.00 and the soil

had to dispose to the dumping area. The total volume of soil to be disposed

is about 35,000 m3.

Below show the calculation how many excavator and lorries required for this

project done in 9 weeks.

If duration to complete = 9 weeks

= 54 days

Bulking Volume

35, 000m3 x 1.15 (bulking factor) = 40, 250 m3

Excavator required

40, 250 m3

= 0.57 = 1 unit excavator1, 300 m3 (output excavator/day) x 54 days

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Lorries required

a) Nos of trip

40, 250 m3

= 4, 025 trip10 m3 (capacity lorry per trip – unlicensed lorry)

b) Time taken per trip

60 minute x 1km (distance) x 2

= 4 minutes30 km/hour (lorry speed)

c) Time to load and upload

Assume = 7 minutes + 4 minutes (time taken per trip)

= 11 minutes

d) Total time taken

4, 025 trip x 11 minutes = 44, 275 minutes

e) No of lorries required

44, 275 minutes= 1.7 = 2 units Lorries

54 days x 60 minutes x 8 hour (per day)

So, for this project, they are requiring to have 1 unit of excavator and 2 units

of unlicensed lorry to complete the project in 9 weeks. This calculation is help

to measure the requirement more accuracy and the contractor will know their

profit also can budget the cost and planning of earthwork operations.

3.3.2 METHOD STATEMENT AND PROJECT PLANNINGThis Construction Method Statement (CMS) provides a summary and

explanation of the construction methods and sequencing of contractors on

site in earthwork operation of this project. This CMS is not intended to

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provide a detailed specification for the proposed works. Rather it outlines the

sequence and extent of construction activities that may not be obvious from

the design drawings alone and that need to be considered in terms of their

impact on the surrounding environment. Detailed specifications for each type

of work will be prepared prior to the start of construction and these will

incorporate any restrictions on working practices demanded by the outcome

of the various environmental and planning studies that will accompany the

planning application, together with any Planning Conditions that may

subsequently be applied.

3.3.2.1 EARTHWORK

1) Scope of Works

The main purpose of this method statement is to outline the activities and

method, which will be used in general to carry out the earthworks in

accordance with the Contract Specification, and details shown in the

drawings.

2) Resources

a) Hydraulic Excavator PC300 for excavation and shifting material.

b) Hydraulic Excavator EX200 for excavation and shifting material.

c) Unlicensed 10-Wheeled Dump Truck for transport material.

d) Back pusher Tractor Ford 5000 for levelling.

e) Vibratory Compacting Roller CA25 for compaction of earth.

f) Concrete mixer.

g) Manpower etc.

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3) Sequence of Works

a) Survey Setting Out

Confirm pre-computation plan and other given references for establishment

of points or lines for our setting out of the Works (e.g. control stations, level

pegging etc). These lines or points will be referenced to enable their

re-establishments as construction proceeds. Original Ground Level (OGL)

survey will be checked on site and verified against the construction drawing

progressively after the site clearing for any discrepancies.

b) Site Clearing

Site clearance shall be carried out within the limit of contract by removal of

fallen trees, shrubs etc. to approved tips. Stripping of topsoil will be carried

out up to about 150mm layer of soil that can support vegetation.

c) Earth excavation

For earth cut fill within the site, earth will be excavated in bulk from

designated high areas within the site to the required depths and levels in

accordance with the drawings. Prior to filling with earth excavated area need

to be survey to confirm excavation level verified by C.O.W/client

representative. For excess excavated earth, these shall be transported,

spread and levelled along side of the site boundary. Compaction of the earth

shall be carried out in layers with a vibratory compacting roller of 20-tonnes

capacity or more in operation. The thickness for fill shall be 300mm each

layer according to specification. However, the swell factories are various from

0.6 to 0.8 depend on the properties of the earth. Hence, at the loose state,

the loose measure thickness various. A trial compaction test will be carried

out to demonstrate the compaction method and numbers of passes to be

used. The method statement of the trial compaction will be submitted

separately. Field density tests as per compaction requirements shall be

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carded out on requests and at an agreed interval depths at earth fill areas

and to be witnessed by authorized Representative. Close turfing to slopes

shall be carried out upon completion of sizeable area. As built level survey

shall be carried out upon work completion and submit to Engineer.

d) Rock excavation & blasting

Excavation in solid rock in open excavation shall mean in rock found in

ledges or masses in its original position, which would normally have to

loosened either by drilling and blasting or be pneumatics tools. All solid

boulders or detached piece of rock exceeding 9 cubic feet in size, but not

otherwise, shall be regarded as solid rock. The solid rock shall be joint

measured with Clerk-of-Work prior to commencement of blasting operation.

The crawler drilling machine shall used to drill the 3" diameter blast-holes

with interval of 1.8m to 3.Om depend on the site condition. Blast-holes shall

be placed in lines parallel to the rock face because a rectangular patter gives

better breakage and vibration control. Depth of drill holes is determined by

height of face desired and distance it is necessary to drill below grade so that

bottom can be controlled. Air compressor shall be used to -remove water

capture inside the blast-hole prior to insert explosive to the blast-hole. ANFO

consists of ammonium nitrate (AN) and fuel oil (FO) at the ratio of 6% (FO)

and 94% AN. Ammonium nitrate shall be used as explosive for blasting rock

into pieces small enough to be handled efficiently by hydraulic excavator.

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The recommended method of making primer with a small diameter cartridge as below:

i. Punch a hole through the plastic film with wooden pricket near the

middle of the cartridge.

ii. Fully insert the plain detonator into the cartridge.

iii. Wrap electrical insulation tape, around the cartridges from the

detonator to the end of the cartridge along safety fuse, securing the

detonator. When priming the blast hole, ensure that the detonator

points to the bottom of the blast hole so that the safety fuse is not bent

sharply.

iv. It is necessary to vary the length of safety fuses when firing multiple

blast hole so that the blast holes fire in the desired sequence. All

safety fuses shall be connected into series and joint to exploder to

commence the blasting works.

v. Safety signboard and red flag shall be placed in the necessary places

prior to commencement of blasting works.

vi. Blasted rock shall be removed and deposited to the area within the

site directed by S.O.

e) Field Density Test

A trial compaction test will be carried out to demonstrate the compaction

method and numbers of passes to be used. The method statement of the trial

compaction will be submitted separately. Field density tests (Sand cone

replacement method) as per compaction requirements shall be carried out on

requests and at agreed interval depths at earth fill areas and to be witnessed

by authorized Representative.

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The requirement of the degree of compaction are:

i. For the topmost 12 in below formation level less than 95% of the

maximum dry density obtained from BS Heavy Compaction Tests.

ii. For the remainder below formation level less than 90% of the

maximum dry density obtained from BS Heavy Compaction Tests.

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PLANNING AND CONTROLLING OF EARTHWORK OPERATION MULTI-STOREY PROJECT BLD 410

3.3.2.2 EXAMPLE OF METHOD STATEMENT FORM

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NO OPERATION SEQUENT OF DIAGRAM MACHINERIES/PLANT

REMARKS

1. Site Clearance and Stripping Top Soil

- For a site condition that full of bushes and vegetation, as well as several huge trees that existed in that area. Site clearance is carried out to all areas occupied by the works area. All the trees, scrub, stumps and bushes within the site boundary are removed completely, including grubbing out of all roots.

1 Excavator,

1 Bulldozer,

1 Back pusher.


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REMARKS

2. Excavation (Cutting Soils) and Removing Unsuitable Materials

A surveyor shall mark at certain point at the site. Marking point using wood sticks are for the purpose of awareness of the machine operator when cutting soils, which written how deep the excavation suppose to be done at certain area at the site.

The excavation had done by used an excavator.

While 2 dump truck is waiting for the excavator to fill the soil on the truck and remove it to the disposal area.

1 Excavator,

2 Dump Truck,


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REMARKS

3. Placing, Spreading and Compaction Of Fill Materials To The Specified Dry Density

The next step is filling the soils is the selected position with has an information of platform level and then spread by the back pusher.

After that, compact the soil using the vibrating roller. This step must do with properly to get a soil with neatly packed together and to make sure that the building that is going to be build is stable and will not collapse.

1 Excavator,

1 Back pusher,


BLD 410

3.3.2.3 PROJECT PLANNING

This is an example for preparing the Critical Path Method. The project planning must included the time duration, cost, resource, management and sequence of work for this SOHO project.

Figure 5 Critical Path Method

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3.3.3 CONSTRUCTION METHOD AND USE OF PLANT

3.3.3.1 PLANNING OF WORK

Prior to the commencement of excavation all the relevant data should be

collected and drawings prepared showing the location of the excavation,

tipping and filling. On these drawings both the excavation and filling should

be divided into section and the quantity of material to be excavated and filled

stated in these sections. This information is required to ensure economic

hauls throughout the work, in which connexion a ‘mass-haul’ diagram is

often. (Institution, 2003)

Where the material is to be excavated consists of different types, and if the

various types have to be used separately in the fill or run to spoil tip, the

quantities of each class of material in each area should be shown on the

drawing. From the nature of the material to be excavated and the method of

its disposal, the type of excavation, the length of haul, and the amount of

compaction necessary, it is possible to select the most suitable type of plant

for:

a) Excavating (when quantities are large it may be economical to use

diffrent types of equipment for the various materials to be excavated).

b) Transporting the excavated material (the length of haul, the nature of

the route selected, the conditions of tiping or speading, and the type of

excavator adopt, should be considered).

c) Placing the material (the methods and plant used for transporting and

compacting the material should be considered).

d) Compacting the material (the nature of the material and the relative

compaction specified are essential considerations).

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3.3.3.2 SETTING OUT

When setting out earthworks it is first necessary to set out the centre line or

other reference lines, and then the lines indicating the top of the cutting or the

toe of embankment. These lines should be ascertained from cross sections

of the existing ground the finished work. Reference pegs should also be

driven into the ground at a fixed distance outside the peg marking the top of

the cutting or the toe of embankment. All levels should be referred to an

established bench mark not subject to subsidence or interference. Batten

profiles are useful to indicate the slopes to which embankments are to be

constructed. In setting out both cuttings and embankments, allowance should

be made for hand trimming and soiling.

Method of Excavation

The types of excavating plant to be used will depend on the materials to be

excavated.

For soft or loose materials, e.g. topsoil, gravel, sand, and most clays, all

types of excavating plant referred to in Clause 7.05 are most suitable and the

choose for a particular job will depend on the conditions of working and

possibly, on the plant available.

When excavation has to be carried out below water level, draglines or grabs

are generally used. In deep or wide water, floating dredgers may be

desirable.

For hardest materials, e.g. stiff clays, shale’s, marls, soft chalk, heavier and

more powerful models than those used for soft or loose materials are

generally required. It may also be necessary to employ rooters or scarifies to

break up the surface of the material before the excavating plant can be used.

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For hard rocks, e.g. all rocks which require drilling and blasting before they

can be excavated, face shovels are most suitable excavators for loading after

blasting. Draglines or grab can be used but not so useful as face shovels.

3.3.3.3 OBSTRUCTIONS

In general, obstructions such as trees, roots, and boulders should be

removed if they are detrimental to or likely to hinder the works.

a) Trees

Trees can be removed using mechanical equipment such as tree

pullers, bulldozers, special rooting attachments fitted to crawler

tractors, and power-operated logging winches mounted at the rear of

track laying tractor.

Alternatively, the trees may cut off at a height of not more than 3 ft

above the ground and the stumps grubbed out by means of winch

gear or high-velocity explosives, or a combination of both.

b) Boulders

Generally boulders which may interfere with the work should be

removed, after breaking down if necessary. In the case of

embankments they may instead be broken down to a size not

exceeding the thickness of the compacted layer of fill. Boulders are

usually broken down by means of explosives although plugs and

feathers or hydraulic cartridges may be used, particularly when the

use of explosives is inadmissible.

There are three methods of dealing with boulders by explosives:

i) Bore a hole about halfway through the boulder into which the

explosive charge is placed and thoroughly tamped.

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ii) Plaster Shot methods. The surface of the boulder should be

roughened by means of a chisel or other implement, removing

any moss or clay coating and thus ensuring a clean surface.

iii) Place a sufficient charge underneath and in contact with the

boulder in a hole made in the ground by means of crowbar.

c) Safety Precautions

Blasting methods should be carried out only by persons thoroughly

conversant with the working methods and precaution and regulations

to be observed in using explosives, and with local police requirements.

To avoid the danger of injury from flying debris all personnel in a

blasting area should retreat several hundred feet and take adequate

cover.

3.3.3.4 EXCAVATING PLANT

Some notes on the types and use of excavating plant are given below:

a) General purpose excavator

This machine is a versatile and universal construction tool capable of

carrying out many different type of front end or jib equipment it can be

used as a dragline, backater or drag-shovel, grab, crane, shovel,

skimmer, or pile driver.

b) Face (or crowd) shovel

Face shovels will dig soft or reasonably hard materials, including soft

chalk, shale and marl, and hard rock when reduced by blasting. They

are a quickly-acting type of machine and work from the bottom of

excavation, digging upwards from the level on which they stand. They

can produce a reasonably clean bottom in many materials. Generally,

the face shovel requires vehicles for transporting the material away

from the excavation.

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c) Dragline

The dragline is suitable for a wide range of materials but it will not dig

such hard material or leave such a clean surface as the face shovel. It

operates from the surface of the material to be excavated, digging

below itself. Where access of vehicles to the bottom of the excavation

is difficult, the dragline working from the top is to the face shovel

working on the bottom; the time cycle of operation is slightly longer

than of the face shovel and its output is rather less. For digging

narrow cuts and depositing alongside it have great advantages over

the face shovel as it has a much greater reach. It is, therefore, used

extensively for cleaning out river beds, forming flood banks alongside

rivers and stripping overburden from mineral deposits. In trench work,

this machine is generally used, with buckets varying in capacity from

¼ to 2 cu.yd, for wide trenches with roughly battered sides. It is

particularly useful for excavating water-logged materials.

d) Backwater or drag-shovel (trench hoe)

This type of excavator is generally used for excavating trenches of

comparatively narrow width and in materials whichare too hard for a

dragline. It is commonly of ¼ to ¾ cu.yd bucket capacity, working on

the surface, will dig in a single cut vertical trenches up to about 15 ft

deep and from 2 to 5 ft wide.

e) Grab

A grab may be used with a dragline excavator or crane on sites such

as foundation pits and trenches where the dragline bucket cannot be

employed. It is also largely used for under water work.

f) Track-laying tractor and scaper

This equipment is capable of both excavating and transporting the

material, and can in certain materials and where suitably routed give a

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considerable degree of compaction in the fill without the use of any

other compacting equipment. It is suitable for use in the softer

materials, but can be used for harder materials if the material to be

excavated is first scarified or broken up with a rooter, or with the help

of booster. It may become uneconomic to use this type of tractor and

scraper for lengths of haul over about 600 yd.

g) Grader or blade grader

Graders or blade graders are used principally for the finished grade for

roadways, aerodrome runways, or similar types of work, and for

spreading a sub-base of ashes or similar material over the area being

treated. They may also be used for bank trimming where the slope of

the embankment is not to steep, and for cutting V-Shaped ditches up

to 3 ft deep in open country. Heavy types of graders are capable of

moving large quantities of earth over short distances and may be used

for constructing the whole earthworks for a roadway from virgin ground

to completed soil information. Heavy types of graders can be fitted

with scarifiers, bulldozer blades, snow ploughs, and side or rear end

elevator loader attachments of the endless belt type.

h) Bulldozer and angle dozer

These machines are primarily designed for spreading and levelling

operations, but are also used for backfilling and excavating shallow

cuttings. They will work satisfactorily in soft or loose materials

provided the tracks will gap. The usual length of push does not

normally exceed 100 – 200 ft.

3.3.3.5 TRANSPORT PLANTa) Tractor-drawn equipment

Scrapers or wagons drawn by track-laying tractors are satisfactory for

the transportation of excavated materials over short distances and

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rough ground, or where tipping is difficult. Normally the distance

should not exceed about 600 yd. If a suitable road is available,

wheeled tractors are preferable and, in any case, where long hauls are

involved they should be used; the larger types then become more

economical. The advantages of the wheeled tractor over the track-

laying type are in the speed of operation, the greater capacities and

the freedom from expensive track renewals. The capacities of

scrapers and wagons range from 4 to 40 cu.yd or more. Hauls of 2 to

3 miles are common for wheeled tractors.

b) Lorries and other rubber-tyred vehicle

Many types of lorries and other from 5 to 20 tons. They include steel-

bodied tipping trucks, and end- or side- tipping or bottom-opening

dump wagons. Special rubber-tyred vehicles not suitable for operating

over public roads are made up to40 cu.yd capacity. Dumpers, with

capacities of up to 5 cu.yd, are suitable for hauls of up to about 1 mile.

c) Belt conveyors

Belt conveyors are finding increasing use for the transport of

excavated material both on short and long hauls. Operating with

suitable loading and spreading equipment to ensure uniform flow,

there are very suitable for moving large volumes of excavation. They

are most frequently used for handling materials of fairly even

consistency, such as sand and gravel, over short distance, but really

large quantities may justify the expense of installing them for moving

almost any excavated material over long distances.

3.3.3.6 COMPACTION PLANTa) Vibrating rollers and plates

These machines are particularly effective on granular soils. The

vibrating roller is a smooth wheeled machine fitted with an engine

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driven vibrating unit. It is made in various sizes ranging from about 3

cwt (hand propelled) to 3½ tons (tractor drawn). Power-propelled

machines, both of the single roller and tandem-type, are available in

the intermediate sizes, the smaller models being hand-guided.

Vibrating rollers have a tendency to dig themselves in when used on

too thick a layer.

b) Construction equipment

Plant used for construction purposes will provide useful compaction if

it is suitably routed to cover the whole area, and if the soil is spread in

sufficiently thin layers. Such compaction may in certain cases be

useful in minimizing or even obviating the use of special compacting

plant. Where material is transported by scraper equipment, the fill may

be distributed in shallow lifts by the scrapers themselves. Where

lorries or dumpers are used, bulldozers and angle dozers should be

used to spread the fill material.

3.3.3.7 EFFECT OF WEATHER ON CONSTRUCTION OPERATION

Very little can be done to protect earthworks from weather as the nature of

the works and their extent generally preclude the use of any covering.

a) Effect of wet weather on plant operation.

Rainfall may so affect the exposed surface of cohesive soils as to

result in interruptions both in the use of excavating plant in the

transport of materials. Airfield works, with their extensive use of

pneumatic-tyred plant over shallow cuts fills, are particularly affected

by intermittent wet periods. Where construction roads are required in

connection with earthworks they should be adequate for the

anticipated traffic, and if possible, laid out and constructed during dry

weather.

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b) Effect of weather on compaction of earthworks.

The moisture content of any soil governs the degree to which it may

be compacted.

If the soil is very wet it may be impossible to achieve a satisfactory

degree of compaction. If the soil is very dry, a large amount of rolling

or tamping may be required to compact is satisfactory. Thus, in wet

weather, work may have to be stopped entirely owing to excessive

moisture near the surface of the soil, while in dry weather it may be

necessary to add water to the soil before compacting it in a fill or

embankment. Both of these difficulties may be diminished if the soil

required for filling is protected as much as possible from direct

exposure to the weather, e.g. by leaving the topsoil or over-burden in

place until the time has come to excavate the subsoil. It is advisable to

compact the soil in its final position in the fill or embankment

immediately after it is placed.

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4 CONTROLLING FOR OPERATION OF EARTHWORK

4.1 INTRODUCTIONEarthworks monitoring checks the performance of the fill during or post-filling,

depending upon the design of the equipment. Normally, the engineering

quantities measured are fill settlement or groundwater level, since both may

have significant effects on performance. Thus if the specification required a

certain maximum settlement after embankment construction, post-filling

settlement monitoring would indicate whether or not settlement was within

the stated limits. Hence monitoring is a control on the engineering

performance of the fill platform.

Monitoring should be regarded as essential for sensitive structures and

where groundwater rise within the fill is a possibility. The techniques available

include:

Surface leveling stations (monuments) to measure settlement of the fill

surface (post-filling).

Settlement plates (rod extensometers) to measure the settlement of

the fill thickness (during and post-filling)

Magnetic extensometers to measure the settlement at incremental

depths of the fill (during and post-filling)

USBR settlement gauges (during and post-filling)

Piezometers to measure to measure the water level in the fill (post-

filling)

Instrument reading should be made for as long as possible after construction,

if necessary during commissioning the structure. In practice, except for large

sites, it is difficult for continuous monitoring to extend beyond a year or so

but, for sensitive structures, it is vitally important that measurements should

be obtained during at least one wet season. If collapse settlement in

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occurring, due to inundation, some indication may be obtained during this

period.

4.1.1 SURFACE LEVELLING STATION (MONUMENT)Such stations should be positioned as soon as an area of fill has been

brought up to finished level. This will mean that the maximum time will be

available for settlement readings, noting that, for obvious reasons, none can

be made using this form of equipment during fill placement itself. Because of

the heavy plant frequenting construction sites, a surfacing leveling station

should be robust, comprising a concrete block about 1 m³ in size, sunk about

300 mm into the fill surface; a metal stud should be cast into the top, from

which optical leveling may be conducted. Readings will give the total

settlement of the fill and that of the underlying soils, if they were not removed

prior to filling.

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4.1.2 SETTELEMENT PLATE (ROD EXTENSOMETER)Unless the natural ground is stiff and will not deform significantly under fill

(and structure) load, surface leveling stations measure settlement of the

underlying soils as well as the settlement of the fill. This is problem where the

natural ground is soil and rock, and where the settlement of the soil beneath

the fill could represent a significant proportion of the total settlement at the fill

surface. In cases such as these, settlement plates (rod extensometers) may

be employed. They monitor fill settlement continuously during and after

placement and not from completion of filling only.

Settlement plates comprise a base plate, usually of the order of one metre

diameter, on to which a suitable length of casing is welded. The base plate is

placed on to natural ground surface with the casing upstanding and fill

carefully placed and compacted around it, during filling works. If it is

necessary to extend the casing vertically upwards in order to cope with

greater fill thickness, additional casing lengths may be welded or screwed on.

From time to time, a rod of known length is introduced into the casing from

the surface to the base plate and a reading of the settlement of the

underlying natural ground is taken by leveling the top of the rod. The surface

of the fill, say 2 m from the casing, is leveled at the same time at say four

position (N, S, E and W) and the result averaged. The difference between the

settlement of the underlying natural ground and the fill surface is the

settlement of the fill. Settlements may be measured a different time during

and after filling and a graph plotted showing settlement against time.

Friction between the fill and the casing means that the fill can hang-up on the

casing, so that the settlement at the surface close to the casing may be less

than the true value. To avoid this undesirable feature, reading of the fill

surface should not be taken too close to the casing. Care should also be

taken to site the settlement plate on reasonably flat natural ground beneath

the fill.

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4.1.3 MAGNETIC EXTENSOMETERThis equipment is often employed where, for example, the compressibility of

one fill type is being compared with the compressibility of another, or where it

is necessary to separate the settlement of the fill from that of the underlying

soil upon which the fill is placed. Magnets are located is the fill about a

central plastic tube grouted into a borehole sunk to hard ground beneath the

fill. A probe lowered down the tube locates the magnets and measures their

position with respect to the base of the borehole (presumed fixed). Results of

the settlements recorded by a magnetic extensometer installed at the site

referred to in Section 8.7.2 are illustrated in Figure 8.8, where the settlement

are recorded as percentage change in fill thickness.

A device which can be built up from the base of the fill, along the lines of the

settlement plate and USBR gauge (describe in the next section) is also

available. It therefore has the distinct advantage over the surface leveling

station in monitoring fill settlement continuously during and after placement

and not from completion of filling only.

4.1.4 USBR SETTLEMENT GAUGEThe USBR settlement gauge (United States Bureau of Reclamation Manual,

1974) comprises a series of cross –arm being separated by standard length

spacers. The basal pipe sections is grouted into hard ground beneath the fill

(perfumed fixed) and further sections added at a rate consistent with the rate

of fill being deposited. Settlements of the various cross-arms are measured

by a torpedo unit lowered down the central pipe sections. Unlike the

settlement plate which provides the total fills settlement, the USBR gauge

indicates the settlement of the fill at each cross-arm location. In this respect,

the device compares with the magnetic extensometer.

Results obtained from a USBR gauge installed in 59 m of the open-cast fill

arm (expressed as percentage change in fill thickness) are plotted against fill

thickness t a log scale and an approximately linear relationship results. There

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is some scatter about the trend lie but this should be expected given the

variable nature of the open-cast fill concerned.

4.1.5 PIEZOMETERA piezometer (preferably a porous ceramic pot, equipped with granular

surround) provides a direct indication of the water level at the location

installed. Dipped at the same intervals at which settlement readings are

recorded it provides direct evidence of any link between settlement and water

rising in the fill (Figure 8.7 is an example).

Because of the importance of establishing such a link, piezometers should be

positioned as close as possible to the settlement measuring device: not only

does this procedure provide maximum information at the position at which

settlement readings are being taken but, by ring-fencing the top of the

piezometer and the settlement device, allows better protection from

construction plant.

Where pore pressures measurements are desired in clay fill, hydraulic

ceramic piezometers are normally employed. They required a much more

sophisticated level of monitoring, with each piezometer controlled via twin

nylon tubes to a manometer in an adjoining gauge hut. Unlike the

Casagrande piezometer which measures positive pore pressures only; such

equipment can measure both positive and negative pore pressures. Further

information may be had from Hanna (1985) or Dunnicliff (1988).

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4.2 SLOPE PROTECTION.Often excavations for earthwork construction intercept the existing

groundwater table, thus interrupting the natural flow of groundwater. This

does not affect the building until the groundwater flow emerges on the cut

slope. If the flow is small, there may be no adverse effects. However, when

the flow is significant and the conditions at the site are favorable, flowing

water can cause seepage forces that will in turn cause the slope to slough or

fail.

To stabilize slopes under these conditions, a heavy material is placed

on the face of the slope. This material is heavy enough to hold down the

existing soil even though seepage forces are acting in an outward direction.

At the same time, it is open enough to carry all the water emerging from the

existing soil. A coarse-graded stone, slag or gravel blanket on top of a

recommended geotextile has proven to be effective in these cases. The

drainage blanket should be designed before construction, but weather

condition during construction will substantially influence the actual need for

such treatment.

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4.2.1 STABILIZATION OF CUT SLOPES

4.2.1.1 INTRODUCTIONCut slopes may require stabilization for the following reasons:

Failure of the slope as originally designed

Strictly limited land-take, requiring steeper slopes than the ground

would safety provide unaided. This is common in an urban or sub-

urban environment.

Ground conditions at the time of construction are found to be less

favourable than those foreseen at time of the site investigation. As a

consequence, either slacker slope have to be adopted (resulting in

increased land –take) or the originally planned side slopes are

maintained but a form of stabilization has to be adopted

Road widening is necessary

For these conditions, stabilization may be achieved by retaining wall, soil

nails, anchors or reticulated mini-piles. Other methods of the stabilization

include drainage and embedded gravity, gabion or crib walls. An excellent

account of the various methods available for slope stabilization.

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4.3 METHODS OF GROUNDWATER CONTROL

4.3.1 Sumps and Ditches Installation of ditches, French drains, and sumps within an excavation

is one of dewatering procedure. The water entering the excavation can be

pumped out. This method of dewatering generally lower groundwater head

more than a few feet but seepage into the excavation may impair the stability

of excavation slopes or have a detrimental effect on the integrity of the

foundation soils. Therefore, filter blankets or drains may be included in a

sump and ditch system to overcome minor raveling and facilitate collection of

seepage. The disadvantages of a sump dewatering system are slowness in

drainage of the slopes, potentially wet conditions during excavation and

backfilling which may impede construction and adversely affect the sub-

grade soil, the space required in the bottom of the excavation for drains,

ditches, sumps, and pumps and the frequent lack of workmen who are skilled

in the proper construction or operation of sumps.

A common method of excavating below the groundwater table in

confined areas is called as cofferdam. Wood or steel sheet piling are drove

below subgrade elevation and bracing are installed to excavate the earth.

Any seepage that enters the cofferdammed area will be pumped out.

Dewatering a sheeted excavation with sumps and ditches is subject to the

same limitations and disadvantages as for open excavations. However, the

danger of hydraulic heave in the bottom of an excavation in sand may be

reduced where the sheeting can be driven into an underlying impermeable

stratum, thereby reducing the seepage into the bottom of the excavation.

Excavations below the water table using sheeting and sump pumping can

sometimes be successful. However, the sheeting and bracing must be

designed for hydrostatic pressures and reduced toe support caused by

upward seepage forces. The bottom of the excavation can be covered with

an inverted sand and gravel filter blanket to facilitate construction and

pumping out seepage water.

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Figure 6 Dewatering open excavation by sump and ditch.

The necessary characteristics of a sump are as follow:

1) The final sump must be deep enough so that when it is pumped out,

the entire excavation will be drained. Digging the sump down that

extra several feet is difficult and sometimes risky. Therefore,

temporary sump at shallower level should be constructed to improve

conditions so that the final sump can be safely constructed to the

proper depth.

2) Water flowing to the sump will carry fines, which are abrasive and

damaging to pumping equipment. The approaches to the sump should

be arranged to remove much of the fines by sedimentation or filtration.

3) The size of the sump should be substantially larger than that

necessary to physically accommodate the pumps. Ample size allows

for a reduction in water velocity so that fines settle out, and the space

provides storage for the sediment between cleanings.

4) The sump should be arranged for convenient servicing of the pumps

and so that accumulated sediment can be readily removed.

Figure 7 Submersible pump for dewatering an excavation.

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4.3.2 Deep-Well Systems Deep wells can be used to dewater pervious sand, rock formations or to

relieve artesian pressure beneath an excavation. They are suited for

dewatering large excavations which require high rates of pumping. Deep

wells also can be used for dewatering deep excavations such as dams,

tunnels, locks, powerhouses, and shafts. Turbine or submersible pumps are

used to dewater by pumping from deep wells for deep excavations. The

advantages of deep wells are that they can be installed around the periphery

of an excavation and thus leave the construction area unencumbered by

dewatering equipment.. Besides, the excavation can be predrained for its full

depth.

Figure 8 Deep well system for dewatering an excavation in sand.

Deep wells for dewatering have a screen with a diameter of 6 to 24 inches

with lengths up to 300 feet. They are generally installed with a filter around

the screen to prevent the infiltration of foundation materials into the well and

to improve the yield of the well. In order to dewater small, deep excavations

for tunnels, shafts, or caissons sunk, deep wells may be used by adding a

vacuum system to the well screen and filter. The addition of a vacuum will

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create a vacuum within the surrounding soil. This will prevent or minimize

seepage from perched water into the excavation. Installations of this type,

require adequate vacuum capacity to ensure efficient operations of the

system.

Figure 9 Deep wells with auxiliary vacuum system for dewatering a shaft in stratified materials.

One of the method to install deep wells is by the reverse-rotary drilling

method. A casing is being drive and jetted into the ground and a bailer or jet

or a bucket auger is used to clean it. In the reverse-rotary method, the hole

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for the well is made by rotary drilling. Soil from the drilling is removed from

the hole by the flow of water circulating from the ground surface down the

hole and back up the (hollow) drill stem from the bit.

Construction dewatering in fine soils can be difficult, because well

yields are often low and it is usually necessary to apply a vacuum to assist

drainage. Ejector systems are therefore ideally suited to groundwater control

in fine soils and have been used increasingly in the UK in recent years (W.

Powrie et al., 1994). A centrifugal or jet-eductor pump pumps the flow from

the drill stem into a sump pit to circulate the drill water. The soil particles

settle out in the sump pit and the muddy water flows back into the drill hole

through a ditch cut from the sump to the hole. The sides of the drill hole are

stabilized by seepage forces acting against a thin film of fine grained soil that

forms on the wall of the hole. Some silt soil may need to be added to the

drilling water to attain the desired degree of muddiness if the hole is drilled in

clean sands. The sump pit should be large enough to allow the sand to settle

out but small enough so that the silt is kept in suspension.

In order to install a straight and plumb screen and riser, the holes for

deep wells should be vertical and deeper than the well screen and riser. The

additional depth of the hole should be provided to put wasting filter material in

the tremie pipe if used. The filter is tremied in after the screen is in place. The

tremie pipe should be 4 to 5 inches in diameter, be perforated with slots 1/16

to 3/32 inch wide and about 6 inches long, and have flush screw joints. The

slots will allow the filter material to become saturated, thereby breaking the

surface tension and “bulking” of the filter in the tremie. The tremie pipe

should be filled with filter material after it has been lowered to the bottom of

the hole. It then slowly raised, keeping it full of filter material at all times, until

the filter material is 5 to 10 feet above the top of the screen.

After the filter is placed, the well should be developed to obtain the

maximum yield and efficiency of the well. The purpose of the development is

to remove any film of silt from the walls of the drilled hole and to develop the

filter immediately adjacent to the screen to permit an easy flow of water into

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the well. Development of a well should be accomplished as soon after the

hole has been drilled so that the efficiency assumed in well design will

maintain the same. A well may be developed by surge pumping or surging it

with a loosely fitting surge block diameter 1 to 2 inches smaller than the

inside diameter of the well screen and should be slightly flexible. The surge

block is raised and lowered through the well screen at a speed of about 2

feet per second.

The amount of material deposited in the bottom of the well should be

determined after each cycle (about 15 trips per cycle) and surging should

continue until the accumulation of material pulled through the well screen in

any one cycle becomes less than about 0.2 foot deep. If the accumulation of

material in the bottom of the screen becomes more than 1 to 2 feet at any

time during surging, it should be bailed clean and recleaned after surging is

completed.

The well should be pumped at approximately the design discharge

from 30 minutes to several hours to clear it of muddy water and sand after it

has been developed. Measurements of well discharge and drawdown may be

used to determine the efficiency and degree of development of the well. The

performance of the well filter may be evaluated by measuring the

accumulation of sand in the bottom of the well and in the discharge.

An airtight seal around the well riser pipe from the ground surface

down for a distance of 10 to 50 feet is required in which a vacuum is to be

maintained. The seal may be made with compacted clay, nonshrinking grout

or concrete, bentonitic mud, or a short length of surface casing capped at the

top. The seal is impossible to attain a sufficient vacuum in the system if

improper or careless placement. This will cause the dewatering system failing

to operate as designed. Besides, the top of the well must also be sealed

airtight. After the wells are developed and satisfactorily tested by pumping,

the pumps, power units, and discharge piping may be installed.

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4.3.3 Wellpoint Systems Another commonly used dewatering method are wellpoint systems as they

are applicable to a wide range of excavations and groundwater conditions.

Wellpoint systems are installed by first laying the header at the location and

elevation called for by the plans. After the header pipe is laid, the stopcock

portion of the swing connection should be connected to the header on the

spacing called for by the design, and all fittings and plugs in the header made

airtight using a pipe joint compound to prevent leakage. Installation of the

wellpoints generally follows layout of the header pipe.

Figure 10 Plan of a typical wellpoint system.

Figure 11 A typical wellpoint system at site

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A wellpoint pump uses a combined vacuum and a centrifugal pump

connected to the header to produce a vacuum in the system and to pump out

the water that drains to the wellpoints. When additional air handling capacity

is required, one or more supplementary vacuum pumps may be added to the

main pumps. Generally, wellpoints connected to a header at a common

elevation capable of lowering the groundwater table about 15 feet. To lower

the groundwater more than 15 feet, A wellpoint system is usually the most

practical method for dewatering at accessible site, the excavation and water-

bearing strata to be drained are not too deep. It may be more practical to use

eductor-type wellpoints or deep wells with turbine or submersible pumps and

wellpoints as a supplementary method of dewatering for large or deep

excavations where the depth of excavation is more than 30 or 40 feet or

where artesian pressure in a deep aquifer must be reduced. Wellpoints are

more suitable than deep wells where the submergence available for the well

screens is small and close spacing is required to intercept seepage. (UTM,

2006)

Figure 12 Use of wellpoints where submergence is small

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Figure 13 Drainage of an open deep cut by means of a multistage wellpoint system.

Vacuum wellpoint systems are installed in the same manner as

ordinary wellpoint systems. It uses a jet casing and filter, except the upper 5

feet of the riser is sealed airtight to maintain the vacuum in the filter. A

vacuum wellpoint system is used to stabilized silts and sandy silts (D10 <

0.05 milimetre) with a low coefficient of permeability (k = 0.1 x 10-4 to 10 x

10-4 centimetres per second) where it cannot be drained successfully by

gravity methods. It is a conventional well system. The partial vacuum is

maintained in the sand filter around the wellpoint and riser pipe. This vacuum

will increase the hydraulic gradient producing flow to the wellpoints and will

improve drainage and stabilization of the surrounding soil. It may be

necessary to provide additional vacuum pumps if there is much air loss to

ensure maintaining the maximum vacuum in the filter column. The required

capacity of the water pump is small.

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Figure 14 Vacuum wellpoint system

Wellpoint pumps, are used to provide the vacuum and to remove water

flowing to the system. The suction intake of the pump should be set level with

the header pipe to obtain the maximum possible vacuum. Wellpoint pumps

should be protected from the weather by a shelter and from surface water or

sloughing slopes by ditches and dikes. The discharge pipe should be

watertight and supported independently of the pump.

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Figure 15 A wellpoint pump used in Sunway Pyramid II project.

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Self-jetting wellpoints are installed by jetting into the ground. Water is

forced out the tip of the wellpoint under high pressure. It can be installed in

medium and fine sand. The water pressures is about 50 pounds per square

inch. To carry out the heavier particles in the coarse sand and gravel, more

water and higher water pressures (about 125 pounds per square inch) are

required. A hydrant or a jetting pump of appropriate size for the pressures

and quantities of jetting water required can be used. The jetting hose which is

attached to the wellpoint riser is picked up either by a crane or hand and held

in a vertical position as the jet water is turned on. The diameter is usually 2 to

3 inches.

Figure 16 Self-jetting wellpoint.

The wellpoint is allowed to sink and raised slowly in the ground. This is

to ensure that all fine sand and dirt are washed out of the hole. Jet water

should be returned to the surface otherwise the point may “freeze” before it

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reaches grade. Therefore, care should be taken. If the return of jet water

disappears, the point should be quickly raised until circulation is restored and

then slowly relowered. It may be necessary to supplement the jet water with

a separate air supply at about 125 pounds per square inch to lift the gravel to

the surface in gravelly soils. Filter sand is required around the wellpoint to

increase its efficiency and prevent infiltration of foundation soils. In order to

form the hole for the wellpoint and filter, the wellpoints should be installed

using a hole puncher and a jet casing. The two halves of a swing connection,

if used, should be lined up for easy connection when the jet water is turned

off and the jetting hose disconnected.

Generally, a wellpoint should be installed in a hole formed by jetting

down a 10- to 12- inch heavy steel casing at where it is to be installed with a

filter. The casing may be fitted with a removable cap at the top. Air and water

may be introduced through and a return of air and water along the outside of

the casing when the casing is jetted into the ground. Jetting pressures of 125

pounds per square inch are commonly used. The casing may have to be

raised and dropped with a crane to chop through and penetrate to the

required depth when resistant strata are encountered. Most of the return

water from a ‘hole puncher” rises inside the casing causing less disturbance

of the adjacent foundation soils. The jet is allowed to run until the casing is

flushed clean with clear water after the casing is installed to a depth of 1 to 3

feet greater than the length of the assembled wellpoint.

Another type of dewatering system is the jet-eductor wellpoint system.

Jet-eductor wellpoints are usually installed using a hole puncher and

surrounding the wellpoint and riser pipe with filter sand. It is installed in the

same manner as conventional wellpoints with a filter as required by the

foundation soils. It consists of an eductor installed in a small diameter well or

a wellpoint screen attached to a jet-eductor installed at the end of double

riser pipes. A pressure pipe is used to supply the jet-eductor and another

pipe for the discharge from the eductor pump. Eductor wellpoints may also

be pumped with a pressure pipe within a larger return pipe. The advantage of

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this type of system compare to conventional wellpoint system is able to lower

the water table as much as 100 feet from the top of the excavation. Jet-

eductor wellpoint systems are most advantageously used to dewater deep

excavations where the volume of water to be pumped is relatively small

because of the low permeability of the aquifer.

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Figure 17 Jet-eductor wellpoint system for dewatering a shaft.

4.3.4 Vertical Sand Drains Vertical drains accelerate the consolidation process by reducing the

drainage path and by reorienting the direction of flow into a more permeable

(horizontal) direction. The earliest version of vertical drains was sand drains

which consisted of a borehole filled with sand (Basu, D. et al., 2000). The

water table in the upper stratum can be lowered by means of sand drains

when a stratified semipervious stratum with a low vertical permeability

overlies a pervious stratum and the groundwater table has to be lowered in

both strata. Sand drains will intercept seepage in the upper stratum and

conduct it into the lower when properly designed and installed Sand drains

consist of a column of pervious sand placed in a cased hole. The cased hole

is either driven or drilled through the soil, with the casing subsequently

removed. Installation of a slotted 1% or 2 inch pipe inside the sand drain can

significantly increase the capacity of sand drains. This is to conduct the water

down to the more pervious stratum. The installation of mandrels into the soil

using a drain stitcher.

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Figure 18 Sand drains for dewatering a slope.

Figure 19 Installation of mandrels using drain stitcher.

4.3.5 Electro-Osmosis When soils such as silts, clayey silts, and clayey silty sands cannot be

dewatered by pumping from wellpoints or wells, it can be drained by wells or

wellpoints combined with a flow of direct electric current through the soil

toward the wells. Creation of a hydraulic gradient by pumping from the wells

or wellpoints with the passage of direct electrical current through the soil

causes the water contained in the soil voids to migrate from the positive

electrode (anode) to the negative electrode (cathode). The water that

migrates to the cathode can be removed by either vacuum or eductor

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pumping by making the cathode a wellpoint. The installation of electro-

osmosis on a dewatering site.

Figure 20 Electro-osmosis wellpoint system for stabilizing an excavation slope.

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Figure 21 Installation of electro-osmosis in a dewatering site.

4.3.6 Cutoffs In order to stop or minimize seepage into an excavation, cutoff

curtains can be used. Cutoff can be installed down to an impervious

formation. There are many methods to construct cutoff curtains. Such cutoffs

can be constructed by driving steel sheet piling, grouting existing soil with

cement or chemical grout, excavating by means of a slurry trench and

backfilling with a plastic mix of bentonite and soil, installing a concrete wall,

possibly consisting of overlapping shafts, or freezing. However, groundwater

within the area enclosed by a cutoff curtain, or leakage through or under such

a curtain will have to be pumped out with a well or wellpoint system.

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Figure 22 Grout curtain or cutoff trench around an excavation.

A cutoff around an excavation in coarse sand and gravel or porous

rock can be created by injecting cement or chemical grout into the voids of

the soil. The voids in the rock or soil must be large enough to accept the

grout for grouting to be effective. Besides, the holes must be close enough

together so that a continuous grout curtain is obtained. Pervious soil or rock

formations are grouted from the top of the formation downward through pipes

installed in the soil or rock. The hole for the grout pipe is first cored or drilled

down to the first depth to be grouted, the grout pipe and packer set, and the

first zone grouted. The hole is redrilled after the grout is set for the second

stage of grouting. This process is repeated until the entire depth of the

formation has been grouted. The type of grout that can be used varies. It

depends on the size of voids in the sand and gravel or rock to be grouted.

The commonly used grouts are portland cement and water, cement,

bentonite, an admixture to reduce surface tension, and water, silica gels, or a

commercial product. Grouting of fine or medium sand is not very effective for

blocking seepage.

Mixing tanks and pump equipment for pressure injection of cement or

chemical grouts vary depending upon the materials being handled.

Ingredients for a grout mix are loaded into a mixing tank equipped with an

agitator. Then, grout are pumped to a storage tank which also equipped with

an agitator. Pumps for grouting with cement are generally duplex, positive

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displacement, reciprocating pumps similar to slush pumps used in oil fields.

Cement grouts are highly abrasive. So the cylinder liners and valves should

be of case-hardened steel. Chemical grouts can be pumped with any type of

pump that produces a satisfactory pressure because of their low viscosity

and nonabrasive nature. There are two types of distribution system for

grouting which are the single-line system and the recirculating system. The

line must occasionally be flushed to ensure that the grout being pumped into

the formation is homogeneous and has the correct viscosity. The grout in a

single-line system is flushed through a blowoff valve onto the ground surface

and wasted. A recirculating system has a return line to the grout storage tank

so that the grout is constantly being circulated through the supply line, with a

tap off to the injection pipe where desired.

Slurry wall is one of cutoff method to prevent or minimize seepage into

an excavation. It can be formed by digging a narrow trench around the area

to be excavated and backfilling it with an impervious soil. Slurry cutoff

trenches can be dug with a trenching machine, backhoe, dragline, or a clam

bucket, typically 2 to 5 feet wide. Such a trench can be constructed in almost

any soil. It can be constructed either above or below the water table.

Generally, the trench is backfilled with a well-graded clayey sand gravel

mixed with bentonite slurry. Thick bentonitic slurry as shown in figure 2.23 is

used to stabilize the walls of the trench until the trench can be backfilled. It is

best mixed at a central plant and delivered to the trench in trucks or pumped

from slurry ponds. (UTM, 2006)

Cleaning of the slurry is commenced in order to remove gravelly or

sandy soil particles that have collected in the slurry, especially near the

bottom of the trench. Fair cleanup can be obtained using a clamshell bucket.

More thorough cleaning can be obtained by airlifting the slurry to the surface

for circulation through desanding units. Cleaning of the slurry makes it less

viscous and ensures that the slurry will be displaced by the soilbentonite

backfill. After cleaning the “in-trench” slurry, the trench is generally backfilled

with a well-graded mix of sand-clay-gravel and bentonite slurry with a slump

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of about 4 to 6 inches. The backfill material and slurry may be mixed either

along and adjacent to the trench or in a central mixing plant and delivered to

the trench in trucks.

Figure 23 Detail of slurry trench.

The other cutoff method is by constructing concrete walls. Concrete

cutoff walls can be constructed by overlapping cylinders and also as

continuous walls excavated and concreted in sections. These walls can be

reinforced and are sometimes incorporated as a permanent part of a

structure.

Steel sheet piling is a very effective method to reduce seepage. The

effectiveness of steel sheet piling depends on the perviousness of the soil,

the tightness of the interlocks and the length of the seepage path. Some

seepage through the interlocks should be expected. Precautions should be

taken in handling and driving sheet piling to ensure that the interlocks are

tight for the full depth of the piling and that all of the sheets are driven into the

underlying impermeable stratum at all locations along the sheet pile cutoff.

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Driving steel sheet piling around the structure, excavate the soil underwater,

and then tremie in a concrete seal is desirable when constructing small

structures in open water. The concrete tremie seal must withstand uplift

pressures. In restricted areas, it may be necessary to use a combination of

sheeting and bracing with wells or wellpoints. Wells or wellpoints can be

installed inside or outside of the sheeting. Sheet piling is not very effective in

blocking seepage where boulders or other hard obstructions may be

encountered because of driving out of interlock. The sheet piling used in

Sunway Pyramid II project in blocking seepage and stabilizing the slope.

Figure 24 Steel sheeting to top of rock. A boulder above the rock can aggravate the situation.

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Figure 25 Steel sheeting in Sunway Pyramid II project to control seepage and stabilizing the slope.

Seepage into an excavation or shaft can be prevented by freezing the

surrounding soil. However, freezing is expensive and requires expert design,

installation, and operation. If the soil around the excavation is not completely

frozen, seepage can cause rapid enlargement of a fault (unfrozen zone) with

consequent serious trouble, which is difficult to remedy. Freezing the soil

around a shaft or tunnel requires the installation of pipes into the soil and

circulating chilled brine through them. These pipes generally consist of a 2-

inch inflow pipe placed in a 6-inch closed-end “freezing” pipe installed in the

ground by any convenient drilling means. Two headers are required for a

freezing installation. One is to carry chilled brine from the refrigeration plant

and the other to carry the return flow of refrigerant. The refrigeration plant

should be of adequate capacity and should include standby or auxiliary

equipment to maintain a continuous operation. An excavation supported by

freeze wall, a typical scenario of freeze pipe spacing, plan and section view

of circular excavation by a freeze wall and a deep excavation supported by

freeze wall.

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Figure 26 Excavation supported by a gravity freezewall.

Figure 27 Typical scenario of freeze pipe spacing and indication which can be connected to a portable refrigeration plant, or liquid nitrogen tanker.

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Figure 28 Circular excavation supported by a freezewall. (a) Plan. (b) Section.

Figure 29 A deep excavation supported by freeze wall.

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4.4 CONSTRUCTION PROCEDURES

4.4.1 SPECIFICATIONSBefore any earthworks are commenced, areas of cut and fill should be clearly

defined. Where necessary, sufficient fencing or barriers should be provided

around trees or other features to be protected. All site activities including

clearing, storage, cutting and filling should be kept away from the root zone

of trees (best defined as the extent of the canopy). Adequate provision

should also be made for the control of erosion, surface water run-off and

siltation. (John, 2007)

The normal necessary specifications are to be prepared to control the

earthwork construction as follows:

i. All rubbish, vegetation and debris should be removed from earthworks

areas prior to the commencement of topsoil stripping. Areas on which

fill is to be placed, or from which cut is to be removed, and haul roads

should be stripped of all topsoil and such unsuitable soft or organic

material as determined by the soils engineer. Special care should be

taken to ensure that organic materials and areas of old uncompacted

filling are not overlooked through being overlaid by other soils.

ii. Stripping should be carried out as a specific operation with areas

being stripped in large enough increments to ensure that there is an

adequate margin of stripped ground beyond any current cutting or

filling operation. Particular care should be taken to ensure that

overspill is not left in an uncompacted state anywhere on the site,

when constructing temporary haul roads.

iii. All stripped material should be deposited in temporary stockpiles or

permanent dumps, in locations where there is no possibility of the

material being unintentionally covered by, or incorporated into,

structural fills.

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iv. Where a fill abuts against sloping ground, benches should be cut into

the ground to prevent the development of a continuous surface of low

shear strength.

v. Previous drains or similar subsoil seepage control systems should be

installed (as necessary) to lead seepage away from all springs and

potential areas of ground water under or adjacent to fills in order to

a) Prevent saturation of the fill before construction of the fill is

complete;

b) Prevent internal ground water pressures which would

detrimentally reduce shear strengths.

vi. Subsoil drains should discharge via flexible jointed pipes to an outlet

approved by the Engineer, preferably a stable watercourse or a piped

storm-water system. The position of all subsoil drains should be

recorded on the "as-built' plan.

vii. The stripped ground surface should be prepared and then inspected

by the soils engineer before any fill is placed thereon.

4.4.2 FILL CONSTRUCTIONThe quality of fill material and required control testing should be determined

and specified before the placing of fill commences. Fill should be placed in a

systematic and uniform manner with near horizontal layers of uniform

thickness (less than 225mm) of material being deposited and compacted

progressively across the fill area.

Before any loose layer of fill is compacted, the water content should be

suitable for the compaction required and as uniform as possible. Any

compacted layer which has deteriorated after an interruption in the

earthmoving operation, should be rectified before further material is placed

over it.

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Fill batter faces should be compacted as a separate operation, or

alternatively, overfilled and cut back.

Where testing shows the compaction achieved in the field to be below the

specified minimum, all material represented by the test should be further

compacted or removed as necessary.

Temporary Drainage and Erosion Control

During the construction period, measures should be taken to prevent

excessive water-logging of surface materials yet to be excavated or

compacted or both, and to prevent fill material from being eroded and

redeposited at lower levels. Such measures should include:

i. The surfaces of fills and cuts should be graded to prevent ponding.

ii. Temporary drains should be constructed at the toe of steep slopes to

intercept surface run-off and to lead drainage away to a suitable

watercourse or pipe storm-water system.

iii. Surface water should be prevented from discharging over batter faces

by drains formed to intercept surface run-off and discharge via stable

channels or pipes, preferably into stable watercourses or piped storm-

water systems.

iv. The upper surface of fills should be compacted with rubber tyres or

smooth wheeled plant when rain is impending, or when the site is to

be left unattended.

v. The completed battered surfaces of fills should be compacted with

sheepsfoot or similar non-smooth compaction plant to reduce runoff

velocities.

vi. Silt traps and retention ponds should be constructed where they are

feasible and necessary. These should be cleaned out, as required to

ensure that adequate silt storage is maintained.

vii. Temporary barriers or fences choked with brush, sacking or the

like,should be used to reduce flow velocities and to trap silt.

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viii. Section of natural ground should be left unstripped to act as grass (or

other vegetation) filters for run-off from adjacent areas.

ix. All earthwork areas should be retopsoiled and grassed or

hydroseeded as soon as possible after completion of the earthworks

and drainage works.

4.4.3 INSPECTION AND QUALITY CONTROLThe soils engineer should provide an adequate level of inspection and

testing, in order to enable him to evaluate properly the general quality of the

finished work, and to enable him to furnish a report as to the compliance of

the work with the specifications. This is not to be construed as a guarantee or

warranty but rather a record of his professional opinion based on reasonable

care.

Visual inspection should be made by the soils engineer or a competent

inspector acting on his behalf at the following times:

i. After any part of the existing ground has been finally stripped and

prepared and before the placing of any fill on that ground.

ii. After any drain has been installed and before the drain is covered by

fill.

iii. At such other times as the soils engineer considers necessary to

enable him to assess the general standard of earthworks and to

reasonably satisfy himself that;

a) Fill is not placed over soft or organic material;

b) All areas of existing ground showing seepage or potential

seepage emission have relief drains provided;

c) Compaction operations are systematic, the water content of fill

material appears on visual inspection to be suitable and the

degree of compaction appears to be consistently satisfactory.

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During the construction of earth fills some or the entire following quantitative

control test should be made on the fill material:

i. Tests to determine whether the water content is suitable;

ii. In situ density tests to determine whether the degree of compaction is

up to the specified minimum;

iii. Where appropriate tests to determine the maximum dry density for the

soil tested in each in situ field density test;

iv. Such other tests as may be specified by the soils engineer for control

testing of fills or particular soil types, providing that the soil property

tested shall be related to in situ density or water content of the fill by a

laboratory investigation. Such tests include shear strength tests, cone

penetrometer tests, and other Proctor needle tests.

Once the filling work is progressing as a steady operation with uniform

construction methods, and provided that:-

i. Adequate construction effort is being maintained;

ii. Adequate visual inspection is being maintained;

iii. The specification requirements are being met.

Then minimum frequency of control testing shall generally be one in site

density test (or equivalent) for each 2000m3 or 1.0m lift of fill. Testing shall

be more frequent than specified above, under any of the following

circumstances:

i. During the first 4000m3 of filling carried out on the project.

ii. On the final layer of not less than 1.0m depth.

iii. When soil type or conditions are variable.

iv. When the soils engineer or his inspector is in any doubt about the

adequacy of construction methods or soil properties.

v. When a decision to reject work based on the judgement of the soils

engineer or his inspector is disputed, and;

vi. When relatively small quantities of fill are concentrated in localized

areas or placed discontinuously over a long period of time.

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The locations of tests should be decided by the soils engineer or his

inspector, who should select them so as to test material likely to be furthest

from the specified quality. In addition, a proportion of tests should be taken at

random locations to check the average standard being obtained.

All field and laboratory test data should be recorded in a systematic manner

that will allow the results to be identified and allow the calculations to be

checked at a later date, if necessary. All control test results should have

recorded the time, date, location and elevation. Test results relating to

sections of fill that have been subsequently removed or reworked and

recompacted should be noted accordingly.

4.5 CASE STUDY

4.5.1 SLOPE STABILIZATION/ SLOPE PROTECTION

For these conditions, stabilization may be achieved by retaining wall, soil

nails, anchors or reticulated mini-piles. Other methods of the stabilization

include drainage and embedded gravity, gabion or crib walls. An excellent

account of the various methods available for slope stabilization. Types of

method to be use for slope protection is:-

4.5.1.1 CONTIGUOUS SPUN PILEA certain exposed slope to be contiguous spun pile immediately to control

soil erosion during excavation works. The CSP for slope protection to be use

after 6 meters excavation from original level, the original level is 21 meter.

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Figure 30 CSP at the SOHO Project.

The method of excavation work step by step, where the contractor made a

few of the slope. This method use because it more effective for site area to

control soil erosion. And then after 6 meter excavated and disposed of the

soil, the contractors use the contiguous spun pile for slope protection. The

contiguous spun pile buried into the soil, the figure show how the contiguous

spun pile to be buried at the third level.

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Figure 31 Re-bar of CSP.

And then the reinforcement bar and concrete work started after all contiguous

spun pile buried into the soil. The gaps between the CSP will closed using

the mortar because to ensure the erosion does not happen and disturb the

working area soon. So, the contractor ensures the retaining wall strong and

safety following the standard in the contract.

Figure 32 CSP side use Mortar.

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The figure shows the using use to fill the gaps between the contiguous spun

piles. It’s important to control erosion and for slope protection.

Figure 33 Layout of CSP.

4.5.1.2 CANVAS METHODThe contractor also use the canvas method for slope protection, its mean that

the rain water does not give effected for the soil properties and the strength

of the soil. Its can prevent from the erosion, and also as an additional method

for slope protection. The canvas lay at each slope; the reason is to ensure

the rain water only flow on the canvas. The figure below show how the

canvas lay by the slope.

Figure 34 Canvas Method

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Figure 35 Canvas to the Slope

4.5.1.3 RETAINING WALLThird method for slope protection is retaining wall. The area of retaining wall

constructed is beside the railway KTM, to separate between disposal area

and railway KTM. This method as a slope protection to ensure the erosion

does not happen. The construction for retaining wall is important and

following the standard specification from CIDB. The retaining wall is use the

precast and in-situ method of construction where the materials make at the

factory and then bring to the site and fixed. After that, the construction

continues by the in-situ method until fixed level. These figures show the

construction of retaining wall using the precast and in-situ method.

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Figure 36 Retaining Wall.

4.5.2 DEWATERING SYSTEM

4.5.2.1 USE THE SUMP PUMPING SYSTEMThe rain water will damage the soil properties, so the strength of the

soil will decrease and settlement will be happen. To protect the

strength of the soil, the water must be flow out from the site area. In

this case, the pumping system is use to flow out the water from the

construction site. Where the water in the site will remove by the water

pump and flowing into the temporary drainage. The temporary

drainage located outside of site area where it located beside the

railway KTM.

The method how the water removed by using the pumping system:-

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a) The water at the foundation will remove by the water pump.

Figure 37 Water Pump.

b) The water flowing through the pipe to temporary sump.

Figure 38 Water Flow.

c) And then, from the temporary hole the water will flow through the

circle culvert with diameter 2 feet.

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Figure 39 Ponding at site.

d) The water flow to the temporary drainage before flow to the large

drainage.

Figure 40 Temporary drainage.

Using the pumping system is effective dewatering system in the

construction site because it easy to set up the system. During

earthwork, this system helps to remove the water in the site. The

water pump had maintained to make sure the project not delay

because of the water. Its also depend on the size of project and

condition of the site. The other method of dewatering system is

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well point system, sump pump system, deep-well system, vertical

sand drain and electro-osmosis.

4.5.2.2 TEMPORARY DRAINAGE.The temporary drainage located near the railway (KTM) where at the

out off construction site. The perimeter of the drainage is half

construction site; it’s around 500 m until main drainage. During the

construction period, measures had take to prevent excessive water

logging of surface materials yet to be excavated or compacted or both,

and to prevent fill material from being eroded and redeposited at lower

levels. Temporary drains should be constructed at the toe of steep

slopes to intercept surface run-off and to lead drainage away to a

stable watercourse. For monitoring, ensure that the Developer/

Contractor maintain the temporary drain regularly (each one week). It

important to make sure drainage will flowing the water smooth such as

dispose any material and rubbish inside. All earthwork areas should

be retopsoiled and grassed or hydroseeded as soon aspossible after

completion of the earthworks and drainage works.

.

Figure 41 Temporary drainage.

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4.5.3 TRAFFIC CONTROLTraffic control is important to make sure the site access smooth and must

logistic. The machineries can move to other position using the access road.

For examples, the tipper lorry can bring the soil from excavation area to the

disposal area without obstructions. This site area provided two ways for

access road is access and exit road. In site area has two ways (to excavation

area and to the disposal area). So, any machinery can move clearly to bring

the soil or other material and also make earthwork smoothly.

Figure 42 Access route.

The figures show the access road for the lorry or vehicles access the site

area and exit road. It effective traffic control to make sure no obstruction

during move the soil and other material.

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Figure 43 Barier gate.

The access road and exit road is logistic, that means easy to going and goes

out after finish work and also easy to see by the people and parties involve

also.

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Figure 44 Wash Pit

Figure 45 Housekeeping.

So, the contractor must make sure the access road in good condition always.

That means, the access road must clean always and remove any material

have on the road such as soil and other materials. The figure shows two

worker cleaning the wash pit area and access road.

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4.5.4 SAFETY CONTROLThe safety control is very important to make sure no accident will be happen

and also trespassers. The contractor had provided a few of the safety control

in this site area such as hoarding, wash pit or wash through, barrier and

signboard.

4.5.4.1 HOARDINGHoarding fixed at surrounding area of construction site, the high for

hoarding is 3 meters. It important and must provide at any construction

site following the CIDB standard because its can protect from the

trespassers, illegal and as the site boundary. For this site, hoarding

also likes a separator between construction site area and railway

KTM.

Figure 46 Hoarding.

4.5.4.2 WASH PIT / WASH THROUGHWash pit located at the exit road behind the public road. Areas of

wash pit makes from steel, concrete and have the hole for trap the

water. There are using the manual operation where the workers used

the water pipe to clean the machineries or vehicles. The main function

for wash pit is to ensure that vehicles leaving the site are clean and

does not dirty the public road.

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Figure 47 Wash pit.

4.5.4.3 GATE BARRIERThe barrier will be open at the working hours and will be close after

working hour. Usually it’s open from 8.00 am until 5.00 pm., using the

manual system.

Figure 48 Gate Barier.

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4.5.4.4 PROJECT SIGNBOARDThe signboard is reference or announcement for peoples about the

project. All construction sites must have the signboard; it usually

located at front site area or at some location where people can see.

The information at the project signboard is title of the project, duration

of the project and also the parties involve in the project.

Figure 49 Project signage.

4.5.4.5 SAFETY EQUIPMENTContractor has to make sure their workers should wearing the safety

equipments such as safety boot safety helmet and etc... The

equipment is very important especially for workers and parties involve

also when enter the construction site. Contractor should provide

precautions of unexpected events. Contractor should provide the good

working space for their workers to work in a good condition. The good

working area can increase the workers productivity and indirectly

provide the good quality of work.

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4.5.5 SETTLEMENT CONTROLMany type of how to control the settlement at the site, such as leveling

method or surface leveling station. Such stations should be positioned as

soon as an area of fill has been brought up to finished level. This will mean

that the maximum time will be available for settlement readings, noting that,

for obvious reasons, none can be made using this form of equipment during

fill placement itself. Because of the heavy plant frequenting construction

sites, a surfacing leveling station should be robust.

Figure 50 Point of sttlement control.

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Figure 51 Settlement Marker Records.

The settlement Marker Record are needed during the measured the level that

had been decided to control. If the level are falling down, the settlement are

occur and must create a solution to settle the problems.

4.5.6 DOCUMENTATION CONTROL

4.5.6.1 STATEMENT OF QUALITY POLICY AND AUTHORITY

It is SENDI BANGGA DEVELOPMENT SDN. BHD. (SBD) objective to

supply client with materials and services to the highest possible quality level

consistent with the requirements of our Client job specification. SBD

recognize the importance of maintaining a high quality system in order to

assure the safety to the general public.

The Quality Assurance Plan defines philosophy, policies and applicability of

our Quality Assurance Program and describes SBD’s organization,

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procurement and construction. The quality control specifications and

procedures which are referred to in this Quality Assurance Plan provide

instructions for the implementation of the Quality Assurance Program.

Compliance to this Quality Assurance Plan and referenced specifications and

procedures is mandatory and shall consistently applied within SBD.

4.5.6.2 QUALITY CONTROL PROCEDURE

PURPOSE

All documents and data are reviewed, approved and controlled to ensure that.

The correct revision of appropriate documents are available at the point of work.

Obsolete documents are promptly removed from all points of issue or use.

APPLICATION

The following types of documents shall be controlled :

1. Project Quality Procedures / Method Statement

2. Quality Assurance Quality Control

3. Specifications / Standards / Method Statement

4. Operation documents including drawings, design calculation etc.

4.5.6.3 PROCEDURE

Control of Document Issue

1. All controlled documents shall, be reviewed and approved for

adequacy by authorized person prior to issue. They shall have their

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issue number, date and signature or initials of authorized person entered

on them.

2. All documents shall be controlled by the department that issues the

document and shall be protected against damage and misuse.

3. It shall be the responsibility of the manager of the department that

issue the documents carry the necessary authorizing signatures and

dates of issue and distributed to the points of use throughout the

company.

Control of Document Use

1. It shall be the responsibility of the supervisor or manager of each work

area to ensure that the correct documents and correct revisions of such

documents are the ones in use in that area at all times.

2. At no time shall the supervisor or manager permit wrongful marking,

use or other action would be defeat the intent of document control.

3. At all times the documents shall be readily available to Client needing

access to their contents.

Control of Document Change

1. Each change in a controlled document shall be initiated / signed and

dated by the authorized person making change.

2. The document carrying changes shall be subject permanent revision

and reissue at the earliest practicable time.

3. Documents shall be directly identified with their revision level using

consecutive numbering.

4. Where practicable, the nature of the change shall be identified in

document by placing description of the change in Revision History Sheet.

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Only Cover page and Revision History Sheet shall be transmitted to

the concerned personnel using transmittal form.

5. Changes to the documents shall be reviewed and approved by the

same department that performed the original review and approval unless

specifically designated otherwise.

6. The review and reissue of the documents shall be reviewed by and

shall receive approval of the department manager. .

7. It shall be the responsibility of the managers and supervisors who are

responsible for performing work affected by the reissued or revised

documents to remove and destroy all obsolete documents from all

points of use upon receiving the revised or reissued documents.

8. Any obsolete documents retained for legal and/or knowledge

preservation purposes shall be stamped "Void - For Information Only"

and kept separate from current documents to preclude unintended use.

9. It shall be the responsibility of the department that issue, reissue or

revise the documents:

a) to distribute documents to their destinations

b) to maintain distribution / master list

10.To notify immediately the Quality Assurance Department and forward

copy of the document to the Quality Assurance Department.

11.Documents issued to personnel and outside company who need a

copy for information only shall be stamped "Uncontrolled".

RETENTION OF DOCUMENTATION

1. It shall be the responsibility of the supervisor or manager at each work

area to maintain and retain all documentation in accordance with legal

and contractual requirements in retrievable and secure manner.

2. The company departments shall establish and maintain active files for

documents. The company departments shall retain all documents in

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active files for a minimum of two years and for as long as they deem

necessary.

3. Unless, otherwise specified, all documents shall be removed from the

active files at the end of two years, indexed and stored in bonded area for

a minimum five years and as long as necessary. While in storage all

documents shall be protected from damage, loss and deterioration.

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5 CONCLUSION

For the conclusion, earthworks sites are amongst the most dangerous

because of the variety of work being conducted and because of the speed at

which some earth moving plant can operate. However, nothing can be built

without some excavation and some transfer soil (or rock) from a one part of a

side to another. That’s why; a proper planning and controlling of earthwork

must have to any contractors.

Danger includes:

a) Failing objects from overhead plant and during demolition of existing

structures

b) Collapse of excavations during site clearance

c) Damage to public utilities such as electricity and gas

d) Blasting operations

e) Heavy plant left at the edges of embankments or at part-completed

retaining wall

f) Heavy earth moving plant on haul roads and elsewhe

g) Reversing plant all over the site

Staffs on site are particularly at risk from earth moving and compaction plant.

They should be protected by warning lights and barriers. Haul surface should

be well maintained because this improves breaking distance; watering during

dry weather helps to reduce the nuisance. Plant should be restricted to

travelling parallel t the dip of the slope, wherever possible.

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6 BIBLIOGRAPHYBurch, D. (2007). Estimating Excavation. Carlsbad: Craftsman Book Company.

Institution, B. S. (2003). Earthworks. Park Street, London: British Standard House.

John, G. (2007). Earthworks. Waikato District Council.

UTM. (2006). GROUNDWATER CONTROL IN THE CONSTRUCTION OF BUILDING. BA. Civil Engineering.

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planning and control earthwork

Documents

project planning

operation of earthwork

planning stage

project contents1

project description

design stage

construction method

method statement