ground improvement assignment

7/28/2019 Ground Improvement Assignment

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CHAPTER 1

INTRODUCTION

Unlike in the past when man just wanted to set up construction work on

already well established land (naturally), nowadays land has to be improved.

This has majorly been due to the increasing demand for construction land

against its availability and the collapse of some landscapes due to landslides

and the like ( A case in point is the Bukit Antagabsa incident of 1993 and the

Bukit Segar incident of March, 2009)

Man has devised all means to improve the properties of land and make it

suitable for construction and habitable. Some of the properties he has tried to

affect include but not limited to:-

Drainage

Permeability

Density

Shear force and Bearing capacity

The objectives of ground improvement include:

Reduce settlement of structures

Improve shear strength and bearing capacity of the soil

Increase factor of safety against possible slope failure of Embankments

and dams

Reduce shrinkage and swelling of soils

There are very many ground improvement techniques that Man has

devised to improve the basic soil characteristics such are; grouting, soil

nailing, tie backs, mechanically stabilised earth walls etc.

Under certain circumstances more than one ground improvement

technique has to be used in order to achieve the overall objectives of

ground improvement. A case in point is the project at Taman Bukit Segara,


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Cheras Kuala Lumpur in which more than one technique was used as

discussed later in this report.

In this report though many techniques exist it mostly tackles the soil nailing

method of ground improvement and briefly hints on tie backs and MSE

walls.


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Chapter 2

LITERATURE REVIEW

This report basically discusses soil nailing as a ground improvement/slope

stabilisation technique based on a brief survey in Cheras, Kuala Lumpur,

Malaysia.

What is soil nailing?

Soil nailing is a technique in which soil slopes, excavations or retaining

walls are reinforced by the insertion of relatively slender elements - normally

steel reinforcing bars. Wikipedia

Soil nailing in other words is an in-situ kind of soil reinforcement technique in

which a slender object is inserted into the soil mass in order to enhance

stability by transferring load from active weak zones of the soil mass to

passive strong zones.

Soil nail walls are retaining walls which are built from the top downwards in

cut situations where the soil has enough apparent cohesion that it can stand

up on its own during construction. structure source

Soil nailing traces its origin far back in 1960s when it was first used in Mexico

and then in Europe in the 1970s. Due to the success of the projects in which

it was used it gained popularity in many places for both Hillside development

and in stabilising Embankments world over Malaysia inclusive.

Soil nail walls increase the resistance to shear forces that may cause the soil

slope to collapse. The steel bars act as the load bearing materials and as

reinforcement structures in the slope. Predominantly, Nails are considered to

operate in tension but there is a possibility of also working in bending/shear

Apart from its former successes it is seen as one of the best slope stabilising

technique because;

It does not require much maintenance post its construction.
http://en.wikipedia.org/wiki/Soilhttp://en.wikipedia.org/wiki/Soil


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It is effective in slope stabilisation

It is also easy to construct and,

Economical.

It is an in-situ kind of ground improvement thus environmental friendlysince it is not a cut excavation and backfill method.

It can be applied to sites where accessibility may be difficult i.e where

working equipments may be difficult to move.

It is not noisy, silent and causes no vibration of the ground making it

suitable for urban areas.

It is flexible and can follow difficult excavation shapes and can be

adjusted to significant variations in soil conditions that be beencountered during construction.

The method is well suited to projects that may be of great concern such

as hill site developments and rehabilitation of distressed structures.


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Chapter 3

METHODOLOGY

3.1. SELECTION

Soil nail walls are normally constructed on slopes whose soil has strong

cohesive forces and hence can stand on their own during construction; soil

should have a temporary sub vertical stability of about 2 metres for a period of

not less than 2 days and the drilled hole should have a capability to stayunaltered for about 3-4 hours or more after drilling it. For this matter soil nail

walls can not be constructed on land whose soil mostly consists of clay, loose

sand or under water.

Landscapes whose soils are stiff fine or cohesion soils, cemented granular

soils, well graded granular soils with appreciable cohesion of about 5Kpa,

most residual soils and weathered rock mass with favourable geological

settings are suitable for soil nail wall construction; putting in mind that the

ground profile is not under water.

If the soils/landscape does not march the afore mentioned properties; there

can be risks such as loosing grout as it is being inserted, collapse of drilled

holes, poor nail to soil interface resistance due to the disturbance of the drilled

holes and localised face stability.

3.2 DESIGN

There are various methods of soil nail wall designing that are used depending

on where the construction is going to take place in respect to construction

regulations, economic considerations and expected time of work i.e.

temporary versus permanent. Particularly in Malaysia there is no particular

regulation regarding the design to but the one laid down by U.S Department of


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Transportation, Federal Highway Administration (FHWA), 1998, is more

recommended since it is cost efficient and practically viable.

The codes of conduct and design manuals include:

BS8006:1995, code of practice for strengthened/reinforced soils and other fills

Soil nailing is discussed in section 7.5: Reinforcement of existing ground in

BS8006:1995. There are two design procedures suggested in this manual; the

two wedge method and log-spiral methods are recommended for analysing

the stability of soil nailed slopes.

HA68/94, Design methods for the reinforcement of Highway slopes by

Reinforcement soil and soil nailing techniques

U.S Department of Transportation, Federal Highway Administration (FHWA),

1998, Manual for Design and Construction Monitoring Of Soil Nail Walls

BS8081:1989 Code of Practice for Ground Anchorage

3.3 INSTALATION

3.3.1 Equipments:

The following machinery needs to be in place in order to commence the soil

nail construction:

1. Man power: Like any other technical civil works soil nailing requires

both skilled and unskilled labour/casual workers for the smooth runningof the project. Perhaps depending on the project it requires more

casual workers at the site than the skilled/professionals and of course

more professionals in the design office.

2. Drilling Equipment: In most cases small hydraulic, track-mounted drill

rigs are used. The rigs are mostly of the rotary/percussive type that

uses section augers or drill rods. The advantage of these is that they

are economical since the mobilisation costs are lowered and do not


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require a large space for their operation as compared to hydraulic-

powered track mounted rigs with continuous flight augers.

3. Grout mixing machine; it should be is recommended that a high speed

shear colloidal mixer is used in order to attain a uniform quality grout.

4. Gunitting /shotcreting machine with a nozzle outlet to control the

amount of water injecting into high pressurized flow of sand and

cement mix.

5. Water suction pump

6. Compressor

Etc. as required in civil works

3.3.2Materials

Grout

Hot Deep galvanised steel Rods

Shortcrete/gunite

PVC pipes

Conditional spraying for the ground

3.3.3 Procedure

Asany other civil engineering work the first thing is to clear the land where the

construction work is going to be done. This may involve removal of

plantation/vegetation, flattening of some part of land either by grading or filling

using soil of better properties, burrowing and reconditioning the wall for

shotcrete surfacing.

Water control measures are then put in place to avoid any alterations during

the construction. For example in the Taman Bukit Segar hill development

project 12metre drainage, beam drain and interceptor drain were constructed.

PVC pipes of about 12 metres in length were inserted into the soil mass. This

way water finds its way out of the soil mass.

The wall is constructed from up to down i.e. the top most landscape is firstnailed and sequentially other layers follow in few steps as laid down below;


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The slope is drilled to about 9-12 metre depth. This is to ensure that the

hardest part of the soil is reached since the main aim is to clamp the less

dense soil to a denser soil so that tensile load is transferred from less stable

active zone of the landscape is transferred to passive strong inactive zones to

attain stability. The drilling was done numerously all over the slope at regular

close spacing of about 0.5-2metres to ensure maximum soil-nail interaction

within the soil mass for its reinforcement. The holes are about 75-200mm in

diameter in order to accommodate the steel rod and a reasonable amount of

grout. The kind of drilling used for slopes whose soil is well suited is known as

open cast method where drilling is done without casing. This way speed is

achieved and costs lowered.

The drilled holes are then flushed preferably using air to remove the dust from

the drilled holes. Rigid Hot deep galvanised steel was then put into the drilled

holes at a slight untensioned declination of about 150. Galvanised steel was

opted for because of its high resistive properties such as resistance to

corrosion.

Fig1: Drilling in progress (Source Manual for Design and construction monitoring of soil nail

Walls, FHWA)


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Fig2: Nail inserted at a slight declination horizontally (Source Manual for Design and

construction monitoring of soil nail Walls, FHWA)

Grouting (in-situ grouting) is then done using Grout of grade 30. Grouting can

also be done simultaneously as the galvanised steel bars are being inserted

into the drilled holes. The grout is applied all way round the steel bar so that

the steel rod is sandwiched between it; this reduces the risk of corrosion due

to rusting of the steel bar.

A bearing plate is then put at the outermost end of the steel rod in order to

hold the nail and grout firmly onto the earth mass (wall).

The wall is then sprayed with shotcrete and a bearing plate is put at the

outermost end of the steel bar. The bearing plate is then fixed on the wall

using a nut and washer.


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Fig3: Spraying of concrete (Source Manual for Design and construction monitoring of

soil nail Walls, FHWA)

Fig4 :( Source: coastal caisson.com)

Then Nail heads are constructed over the steel rods and bearing plates. This

is done so that the steel rods, bearing plate, nut and washer are not left

exposed and are well attached to the wall. A simple conical/trapezoidal

shaped structure made out of concrete can be constructed over each steel

rod or the whole wall surface can be plastered but the former is more

economical.

Fig5: Nail head


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The above procedures are followed till the whole slope is nailed.

3.4 QUALITY CONTROL/ASSURANCE

It is true that not all construction works meet standards. Thus many structures

have found their way in collapsing after a given time,t thus leading to both life

and economic loss. Thus assurance of quality should be right from the start till

the end of the construction and periodical surveys should be carried out in

future though soil nailing does not require much inspection after constructionbut never know some catastrophe may occur. So to ensure quality preliminary

and working pull outs were taken.

Cone penetration test (CPT)

In this test a penetrometer with a conical tip and standard geometry is pushed

vertically into the ground at a standard rate of 20mm per second. Penetration

at this rate is fully drained for sands with non plastic silt contents of up to 10%

(Carraro et al.2003). This test is conducted during the site exploration to

determine the cone resistance, qc

Where, qc = vertical force acting on the tip of the penetrometer

The base area of the tip

(1000mm for the standard penetrometer with diameter of35.7mm)

Fig6: Photographic view of nail heads


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The qc can then be used to conclude on the nature of soil. Of recent invention

this test can also help in determining friction along a lateral sleeve and shear

wave velocities, pore pressure and other quantities with the help of seismic

shear waves.

The test is normally used because of its simplicity, speed and probably ability

to maintain a continuous profiling.

Cube test ; this was do check on the quality of the grout mix used.

Curing test/test panel; this was to test the quality of shortcrete used for

reinforcements.

Weight bearing capacity of the steel rods (nails) has to be determined and

ensure that the minimum load can meet the load on the soil mass.

Seasonal monitoring

Apart from the monitoring by the site resident Engineer, periodical monitoring

is done by the Local authorities such as Dewan Bandaraye Kuala Lumpur (a

body responsible for monitoring all construction work in Kuala Lumpur) after

every six months.


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CHAPTER 4

ANALYSIS OF SOIL NAILING

Soil nailing is best suited for slope stabilisation in which the soil mass can

stand on its own.

3.1 FAILURE MODES IN SOIL NAILING AND CORRECTION

PROCEDURES

Basically, for the soil nailing technique discussed in this report, where the nail

head is attached to the ground, only one failure mode is exhibited. It is as a

result of the sliding of the soil wedge moving down and out thus dragging the

nails along with it. This movement results from shear stress that develops

along the soil interface with the nails. The resistance between a nail in

question and the soil beyond the sliding wedge can then be mobilized.

The wedge tends to drag the nail, the stable soil mass drags it in the opposite

direction and the nail itself pulls the wedge. If the resistance of the soil nail is

sufficient, the wall-nail-soil system will be stable; otherwise the soil wedge will

slide carrying along the nails with it.

Fig 7: Failure mechanism in soil nailing

This makes it necessary to put into consideration the wedge factor when

designing a soil nail wall. In addition when designing a soil nail wall a slope


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stability mechanism with an approximately shaped slip surfaces that can

handle the nails is used.

Estimate design mechanisms basically rely on the assumed shape of the slip

surface, this can be done by estimating the lateral and vertical spacings of the

nails sh and sv respectively, and an assumed lateral earth-pressure

distributions. This defines an influence area for each nail which may be

multiplied by a factor of safety, FS, in order to calculate the required

resistance from each nail, Treq

Treq= (FS) h sv sh(i)

Where h is the horizontal vertical stress. The minimum value of FS is 2.

Analysis will always be backed by the type of problems and applicability of the

said analysis method.

There are basically two principles that can be followed when analysing the

applicability of soil nailing that is to say, the limit equilibrium method and finite

element method.

Limit equilibrium Method; This is used to evaluate the overall stability of the

soil nail wall and helps in determining the total required nail forces required to

support the soil mass.

Finite Element Method is normally used to predict stresses, bending moments

and axial loads in the structural components, movement of the wall and thesettlement in the supported ground.

3.2 Soil nailing as compared to tie backs and Mechanically Stabilised

Earth (MSE) walls

We should appreciate the big similarity between soil nail walls and tie backs

as both are in-situ reinforcement methods but there also differences which

may make one more suitable than the other under given conditions. Though

MSE walls are slightly different they also exhibit some similarities with soil


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nailing as a method of ground reinforcement since they also exhibit a passive

kind of reinforcement.

The table (Tab 1) below as adopted from the FHWA,i998, Manual for

construction and Design of soil nail walls. Shows the principle comparisons

amongst soil nailing tiebacks and mechanically stabilised Earth walls.

Soil Nail Walls Tie backs MSE Walls

Construction

Top-Down (Cut

in-situ)

Top-down(Cut in

situ)Downup(fill up)

Reinforcements

are Drilled and

grouted through

both passive and

active zones

Reinforcements

are only in active

zones.

Sheets for

reinforcement are

sandwiched

between active

and passive

zones.

Reinforcements

are Actively

stressed

throughout

excavation

process.

They are Actively

stressed only at

present

excavation point.

Passively

stressed as fill

construction

progresses.

Loads in

reinforcement

decrease from

top to bottom.

There is almost

uniform load

distribution.

Loads in

reinforcement

decrease from

bottom to top

Wall behaviour

Facing caries

only load not

supported by

nails.

Facing caries full

soil dressing

Facing caries

only load not

supported by

reinforcement

sheets.

Load transfer

between soil and

Load never

distributes to the

Load transfer

between soil


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reinforcement

occurs along full

length of the soil

nail.

active zones mass and nail

occurs along full

length.

Tensile forces on

reinforcements

are due to gravity

forces acting on

the soil mass in

active zones.

Tensile forces in

Anchor results

from equilibrium

between tensile

forces applied to

the anchor head

during stressing

and self weight of

soil in active

zones.

Tensile forces on

reinforcements

are due to gravity

forces in active

zones of the soil

Soil is partially

confined by nails.

Soil is confined

by facing only.

Soil is mostly

confined by

reinforcement

depending on

reinforcement

used and

spacing.

Maximum wall

deflection is at

the top of the

wall.

Maximum wall

deflection is mid

way the wall

Maximum

deflection mostly

at lower third

level of the wall

Design approach

(internal)

Limit equilibrium

approach is used

to

Empirical Earth

pressure

approach is used

to derive

reinforcement

stress, which is

equated to

reinforcement

Empirical earth

pressure

distribution is

used to calculate

reinforcement

stress, which is

equated to

reinforcement


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capacity to

determine safety

factor against

rupture and pull

out.

capacity to

determine the

safety factor

against

reinforcement

rupture and pull

out. (but this is

done differently

from the one for

tie backs)

Reinforcement

strength and pull

out resistance is

calculated once

throughout the

entire wallconstruction or at

intermediate

stages.

Reinforcement

strength and pull

out resistance is

calculated at

each and every

stage of

construction

basing on the

anchor capacity

required for the

facing to

structurally resist

the lateral earth

pressure.

Reinforcement

strength and pull

out resistance is

calculated at

each and every

stage of

construction in

order to resist thelocal lateral earth

pressure in the

tributary area of

the

reinforcement.

Facing and

facing-nail

connection

system are

checked for

possible failure

modes such as

flexural and shear

using empirical

Facings such as

soldier piles and

facing tieback

system is

checked for

possible failure

modes under the

installed tie back

pre-stress

Facing-

reinforcement

system is

checked for

possible failure

modes using

empirical earth

pressure

distribution at the


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Tab 1

Though soil nailing is one of the best technique for soil wall reinforcement bit

may not be always applicable and therefore another technique such as tie

backs and MSE walls may be applied as discussed below.

Soil nailing should be given priority over tie backs where applicable because

There is no need for high capacity structural facing since most loads

are not transferred to the excavation facing in soil nailing.

Soil nails have a very small diameter and therefore are less obstructed

in heterogeneous cobbles boulders and any other hard obstacles

unlike the soldier piles used in tie backs whose diameter is so large.

Easier to construct and less time spent during construction of soil nails

than tie backs because; no soldier piles required, no prestressing of

soil nails and the construction equipments are less thus mobile and

quite.

The vertical components of the nail reaction at the facing are lower

than those for tie backs and are more evenly distributed on the entire

earth pressure

distribution at the

facing

facing.

Design approach

(external)

Reinforced zone

is treated as a

rigid body,

evaluating

overturning and

bearing capacity.

Only slope

stability behind

wall is typically

evaluated, but

bearing failure of

the gravity wall

must be

evaluated under

adverse

foundation

conditions

Reinforced zone

is treated as rigid

body, putting;

sliding

overturning, and

bearing capacity

into

consideration.

Slope stability

behind the wall is

also evaluated


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excavation wall and hence no need for significant embedments in soil

nailing as its the case with tie backs.

There is higher system redundancy in soil nailing than in tie backs thus

consequences of failure are less.

For soils with low water content granular back fills that are predominantly

frictional in nature MSE walls may be used instead of the soil nail walls since

properties of soil in MSE walls can be pre-selected.

The nail excavations are more suited for temporary and permanent structures

as compared to tie backs because more movement is required for

mobilisation of nail resistance than tie back resistance.


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CONCLUSION

Applicability of any ground improvement technique will always depend on the

number of soil factors such as its properties and the topography of the

landscape so always feasibility of the ground improvement technique to be

used must be evaluated. The feasible ground improvement technique taken

should always meet the economic/financial plan.

Though there are various methods of stabilising walls soil nailing should be

given priority where soil conditions are favourable given its economic

advantages and so ever.


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Appendix ASAFETY CONSIDERATIONS

Before any construction work takes place an authorisation by the local bodies

must be obtained. One of the pre requisites before authorisation is given is to

provide a well detailed safety plan for the anticipated risks together with the

mitigations to be undertaken.

Soil nailing as a project is very risky since it involves working at heights, using

electrical equipments, chemical components. So to ensure safety at the site

guidelines should be laid out and strict regulations imposed on following them.

The following are some of the guide lines that may be followed

Safety Precautions While At Site in Soil Nail Wall Construction(Adapted from Safety, Health policy and Manual, Visage Contractors Sdn. Bhd.)

1. Personal safety

a. All workers on site are supposed to observe and abide by the rules and

regulations as laid down and approved at the construction site

b. One should eliminate any obvious hazardous element at the site by

oneself or inform the concerned personnel such as site supervisor.

c. Maximum care should be undertaken while walking or moving about

the site in order to avoid slipping, falling or tripping.

d. Never stand under a suspended load. One should stay alert at all

times.

e. Ensure that tools or other materials on scaffolds or other elevators are

not left where they may dislodge and fall

f. Never throw tools, materials or equipment up to down from one

working level to another-use safe working method.

2. Personal Protection equipment

a. Wear face shield when engaged in grinding work.

b. Wear gas welding gaggles when engaged in gas cutting work.

c. Use welding shield when engaged in welding work.

d. Use safety belts whenever working at heights greater than 3meters.

e. Wear clear safety glasses when working at the site (not specifically for

cutting, welding etc)


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f. Wear ear plugs when working in noisy environments.

g. Always wear working garments safety boots and helmet inclusive.

3. Excavations

a. For excavations more than 1.5 meters deep, safety precautions should

be taken such as slope edge, barricade, ladder etc.

b. Excavation work should be left to competent work men but under tight

supervision.

c. A proper sheet pile should be constructed around inside the excavation

pit 9incase there is sand mix with soil and water).

d. The excavation pit should be inspected on a daily basis and hazardous

things such as unprotected cables, leakages on gas cylinder checked

on.

e. In case of any changes in the support soil or surrounding surface

condition, no one should enter and immediate action should be taken

such as reporting the condition to safety officers or supervisors

f. Safe ladder access should be placed into the excavation pit.

g. Excavation should not be too close to any vehicle or scaffold erection.

h. A proper barrier should be created around the excavation pit.

i. Remember to always wear protective equipment such as helmet and

suitable footwear.

4. Carpentry

a. Erection, dismantling of form work must be carried out under

supervision of competent supervisor.

b. Timber and plywood should be clamped firmly at designated platform

c. All off-cut from timber should be kept under a rubbish pit

d. Tidiness/housekeeping should be carried out at all times whilst on site.

e. Hammer, measuring tape chisels and other tools should not be left at

edges.

f. Always remember to wear the right protective equipments such as face

mask, helmet and safety boots while at work.

g. Incomplete form work area must be barricade temporary for exampleusing timber or warning tape.


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h. Underside form work erection (slab) that is to be concreted must be

labelled as dangerous and barricaded.

5. Concreting /casting

a. Before concreting commences, firm and proper working platform must

be installed and erected by competent workmen.

b. It should be carried out by competent work men under supervision.

c. Always remember to wear protective equipment whilst carrying out

concreting work.

d. Signalman should be used during concreting using the crane.

e. Sufficient lighting must be in place whilst concreting at night.

f. Edge area should be barricaded immediately after concreting.

g. Support form work should be barricaded to avoid other workers from

entering whilst concreting is in progress.

h. Do not exceed/overload the concrete bucket to avoid spillage.

6. Working At heights

a. Always use your safety belt whilst working at heights and remember to

check your belt for any damages or defects.

b. Use a life line when you cannot find a secure place to attach your

safety belt/harness lanyard. Remember your safety belt/harness is only

as strong as the point where it is attached.

c. Excavations and trenches more than 1.5 meters (5ft) deep must have

an access/exit ladder at travel intervals of 7.6 meters. (25ft).

d. Do not attempt to carry tools or materials up or down ladders and

monkey boards. Use a rope and bucket to raise or lower your tools or

materials.

e. The top of an erected ladder should be properly extended at least 60

centimetres (2ft) above the landing. The ladder should be properly

secured to the landing to prevent falling or slipping.

f. When handrails, toe boards, safety nets, platforms or scaffolds are to

be removed to perform work, they should be replaced as soon as the

work is finished.


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g. In case of dizziness or illness the worker should immediately tell the

supervisor and s/he should stop working at heights.

h. Remember not to throw or toss materials or any other objects to the

ground whilst at heights.

7. Safety signage/signboards

There should be signage at the site which are understood by all workers

undertaking the project and they should not be ignored by whosoever is on

site. Workers and community members may undertake a safety training

program before construction commences to ensure effective communication

at the site through use of signage and sign boards.

The following safety and signage tools must be installed at the site before

commencing work;

First aid box which is fully equipped with all the necessary elements

Fire extinguishers at different points on the site; they should be located

in such a way that they are easily accessible,

Keep clean sign board

Danger openings/emergency exits

Scaffold in progress

Safe for use

Alarm which is well functioning

Call centres for easy communication

8. Emergency Procedures

In case of fire;

Sound the alarm

Extinguish

Call the fire department or emergency service

In case of injuries;

First aid should be applied to the patient

Consider visiting a clinic for minor injuries


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Call ambulance service in case of serious injuries

Report injuries/discrepancies however minor/small they may seem.

All workers are advised to offer a helping hand in case of any emergency but

should always ensure their safety first.

Proper communication among workers should be emphasized.

Re-enforcement

To ensure security at the site the following records may be taken;

An emergence response plan should be put in place fully illustrating the

procedures to be taken in case of any emergence.

Records of all workers; a roll call should be taken at least twice a day

(at arrival and departure time) for big projects.

Checklist of all gadgets/machines/instruments: it should fully illustrate

their working condition periodically.

Accident report forms should be in place

A safety program sheet

Safety statistics


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Appendix B - BRIEF INFORMATION ABOUT THE SITE VISITED FOR THIS

ASSIGNMENT

The case study was carried out at Taman Bukit Segar hill development

project, Cheras Kuala Lumpur, Malaysia.

Topography: it is a highland (hill) which is over 15m high. The slope is a 90o

slope.

Engineering consultants: Kamal TI Sdn. Bhd.

This project was intended to protect the residents around the area from a

threat of a Land slide due to the slope instability. The slope had once

collapsed leading to great economic loss and lives ceased.

The inner layers of the Earth component of the area consist of hard rocks and

thus a soil nail wall is applicable since the earth can stand during construction

The high water content in the soil loosened the top layers thus leading to the

slope instability which later resulted into its collapse in March, 2009 leaving

many dead and others in fear. This awakened the concerned authorities and

means to prevent further collapsing had to be devised. The photograph below

gives a glimpse at how the hill was like before the construction of the soil nail.

(Source: Landslides under microscope-Web blog)


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A slope stabilisation technique had to be set up and the drainage also had to

be improved to make the area below the highland habitable. The engineering

consultants deemed it necessary to set up a soil nail wall and vertical

drainage system to cater for the stability of the wall.

The photograph below shows how the place was like as at the time of the site

visit.

.

Source: Pictures taken at Bukit Segar on 22nd October, 2009)


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APPENDIX C- PHOTOGRAPHY

a-d,i- future engineers struggling their way up the soil nailed wall, f-sheet pile

at the site,e- a clear view of the nail heads,

a b cd

e f g

h ij k

mn

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REFERANCES

Rodrigo Salgado, The Engineering Of Foundations, Mc-Graw Hill International

Edition.

Petros P. Xannthankos, Ground Anchors And Anchored Structures Wiley

Inter-Science Publication

Coastal Caisson Corporation,

http://www.coastalcaisson.com/en/products/soilnailing/ (accessed on14th

November, 2009)

Landslides under Microscope,

:http://landslidesgib.blogspot.com/2008_12_01_archive.html (accessed

on1st October, 2009

Liew Shaw Shong, Soil Nailing for slope Strengthening, retrieved from

http://www.gnpgeo.com.my/download/publication/L_09.pdf - (on 14th october,

2009)

U.S Department for Transport, Federal Highway Administration, (1998),

Manual for Design and Construction Monitoring of Soil Nail Walls, (FHWA-SA-

96-069R) Retrieved from http://isddc.dot.gov/OLPFiles/FHWA/010571.pdf,

accessed on 5th October, 2009

Visage Contractors Sdn. Bhd. And JV. Suhati Sdn. Bhd., Safety, Health Policy

and Manual, Kuala Lumpur, Malaysia, unpublished.

Landslides under microscope, http: //landslides-

gib.blogspot.com/2008/12/landslide-caused-by-human-activity.html Accessed

on 14Th October, 2009


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Structure Source, http://

www.structsource.com/retainingwall/types/soilnail.htm. Retrieved on27th

October, 2009

Coastal caisson, http://www.coastalcaison.com/en/products/soilnailing.jpg

(accessed on26 October, 2009)

ground improvement assignment

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