geotechnical engineering investigation subdivision …... · accordance with ‘the guidelines for...

KGA Geotechnical Limited

Supporting the Construction Industry since 1990

7A William Pickering Drive | Albany | Auckland | P O Box 302 361 | North Harbour | Auckland 0751

Phone 09 478 6655 | [email protected] | www.kga.co.nz

9585-6A

1 June 2018

GEOTECHNICAL ENGINEERING INVESTIGATION

SUBDIVISION

223 FALLS ROAD (LOTS 1 TO 47)

WARKWORTH

Prepared For:

SF Estate Ltd

PO Box 95

Victoria Street West

Auckland 1142

Geotechnical Engineering Investigation 9585-6A

Subdivision - 223 Falls Road (Lots 1 to 47), Warkworth

1 June 2018

CONTENTS

1. INTRODUCTION ...............................................................................................................................1

2. SITE DESCRIPTION .........................................................................................................................1

3. PROPOSED DEVELOPMENT..........................................................................................................2

4. DESK STUDY....................................................................................................................................2

4.1 Published Geology and Regional Geomorphology...............................................................3

4.2 Geomorphological Walkover.................................................................................................3

5. FIELD EXPLORATION .....................................................................................................................4

5.1 Hand Auger Boreholes .........................................................................................................4

5.2 Machine boreholes................................................................................................................5

5.3 CPT Probes ..........................................................................................................................5

6. SUBSURFACE CONDITIONS ..........................................................................................................6

7. MECHANISM OF FAILURE..............................................................................................................8

8. LABORATORY TESTING.................................................................................................................9

9. SLOPE STABILITY.........................................................................................................................10

9.1 Relic Slopes ........................................................................................................................12

10. GEOTECHNCIAL CONSIDERATIONS ..........................................................................................13

10.1 Underfill drainage................................................................................................................13

10.1.1. Northern Instability Feature (Lots 17 to 27) ........................................................................13

10.1.2. Gully Infill Drainage.............................................................................................................14

10.2 EARTHWORKS OPERATIONS .........................................................................................14

10.2.1. General ...............................................................................................................................14

10.2.2. Gully Materials ....................................................................................................................15

10.2.3. Filling...................................................................................................................................15

10.2.4. Excavation ..........................................................................................................................16

10.2.5. Pre-existing fill.....................................................................................................................16

10.2.6. Batter Slopes ......................................................................................................................17

10.2.7. Compaction Control ............................................................................................................18

10.3 Roading Subgrades ............................................................................................................18

10.3.1. Main Road...........................................................................................................................18

10.3.2. Common Access.................................................................................................................19

10.4 Retaining Structures ...........................................................................................................19

10.4.1. General Retaining Comment ..............................................................................................19

10.4.2. Road Alignment Retaining Structures.................................................................................19

10.4.3. Gravity Type Wall................................................................................................................20

10.4.4. Timber Pole Retaining Wall Type .......................................................................................20



1 June 2018

11. FINISHED BUILDING PLATFORMS..............................................................................................21

12. ENGINEERING OBSERVATIONS AND TESTING ........................................................................21

13. LIMITATIONS..................................................................................................................................22

Attachments:-

Sheet 1 Site Plan

Sheet 2 Proposed Subdivision Layouts and Subsoil Drainage Plan

Sheets 3A-3C Cross Sections

Sheets 4A-4Y Hand Auger Borehole Logs AH1 to AH25

Sheets 5A-5D Scala Penetrometer Results

Sheets 6A-6E Machine Borehole Logs and Photographs

Appendices:-

Appendix A – Proposed Design Drawing Set by Chester Consultants Ltd

Appendix B - Slope Stability Calculations

Appendix C - CPT Results

Appendix D - CU, Multi-Stage Triaxial Testing

Appendix E – Unconfined Compressive Strength (UCS) with Young’s Modulus

Appendix F – KGA Initial Geotechnical Assessment, Ref: 9585-3, dated 2 September 2016



1 June 2018 1

1. INTRODUCTION

At the instruction of SF Estate Ltd we have carried out a geotechnical engineering investigation for

the proposed residential subdivision (Lots 1 to 47) at 223 Falls Road, Warkworth.

Our scope was to carry out a detailed desk study of available geotechnical information for the site,

perform a detailed site walkover, and supplement existing in house geotechnical data (KGA

Geotechnical Initial Geotechnical Assessment Report, Ref: 9585-3, dated 2 September 2016,

attached as Appendix F) with an additional twenty five hand auger boreholes, five machine holes

and six static cone penetrometer tests (CPT) probes. The information has been used to assess the

ground conditions, review site stability and provide general geotechnical considerations for the

proposed development.

This report is prepared in support of an application to Auckland Council for a Resource Consent for

the subdivision.

2. SITE DESCRIPTION

The subject property is legally described as Lot 2 DP 210933 with a total plan area of 92023m². It is

irregular in plan shape and bounded to the north by Falls Road, to the south by Falls Road River

Esplanade Reserve, and to the east and west by rural residential properties.

Historic instability was noted close to the existing barn structure and within the neighbouring

property to the east. Active shallow instability in the form of soil creep in the northwestern part of the

property was also present on the moderate to steep slopes on the property.

An existing barn structure is situated central along the northern boundary of the property, and an

existing dwelling with swimming pool and tennis court is located approximately 70m along a

driveway extending to the south of Falls Road. Other shed and outhouse structures are scattered

around the property.

A detailed description of the geomorphology of the property can be found in Section 5.0 of the

September 2016 report (Appendix F). In general, the ground surface at the property is governed by

a series of ridges and gully features.



1 June 2018 2

The northern portion of the property falls at varying grades to the south and southwest from the

ridgeline along Falls Road. A series of steep sided bush lined gully features incise the property,

draining to the Mauhurangi River to the south. A prominent river cliff feature is situated along the

southern portion of the property, with an alluvial plain at the southwest of the property. Some

amount of ground modification involving excavation and filling has taken place around the existing

access tracks, sheds, tennis court and dwelling at the property.

The subject area comprises of the proposed new Lots, a central access road and other accesses, as

shown on the Proposed Design Drawing Set by Chester Consultants Ltd (CCL) (presented in

Appendix A). The western portion of the property is not included.

3. PROPOSED DEVELOPMENT

The concept drawing, provided to us by Buckton Surveyors Ltd shows that it is proposed to

subdivide the property at 223 Falls Road into 47 Lots (not including the original dwelling), plus a

Future Auckland Council Property at the western portion of the site. Lots 1 to 47 are to become rural

residential properties. Preliminary earthworks drawings provided by CCL indicate that formation of

the subdivision will involve modification of the ground profile by excavations into the ground of up to

approximately 4.5m for the proposed road access through the main gully area, and filling by up to

approximately 4m for the proposed road adjacent to proposed Lot 27.

The drawings indicate that retaining walls up to 2m high will support cut and fill faces at various

locations for Lot formation.

4. DESK STUDY

A review of available in-house geotechnical information relevant to the site was made as part of the

desk study. The information identifies that nearby properties are underlain by residual soils derived

from weathering of Waitemata Group materials (Pakiri Formation).



1 June 2018 3

4.1 Published Geology and Regional Geomorphology

The geology of the site and surrounding area is detailed on the Geological Map of New Zealand,

Map 3, Auckland (Scale 1:250,000). This shows the northern and northeastern portions of the

property to be underlain by mudstone and graded sandstone of the Pakiri Formation, part of the

Waitemata Group. It is described as having alternating thick-bedded mudstone, volcanic-rich,

graded sandstone and siltstone. These materials weather to variable strength silts and clays at

shallow depths. The southern portion of the property, situated adjacent to the Mahurangi River, is

shown to be underlain by Holocene river deposits which may comprise sand, silt, mud and clay with

local gravel and peat beds; these types of deposits are often variable in strength.

Historic aerial images viewed for the regional area indicate the presence of a pronounced

headscarp feature within the properties at 91 and 93 Falls Road (to the east of the subject site) with

hummocky ground identified downslope of the scarp feature, including the subject site. The

headscarp is likely the result of historic ground movement which may have also cause movement of

the subject site. Secondary instability has later occurred, as evident by the observations of small

scale head scarps across the site, and may mask features of the larger slope movement.

The Mahurangi River meanders along the southwestern site boundary. On a wider scale, the

Mahurangi River meanders in a similar scale both upstream and downstream of the site, suggesting

that the meander is due to natural river process and underlying ground, rather than a local event on

the site causing a diversion of the stream. The erosion of the outside bends of the stream and the

deposition on the inside bends further indicates the meanders being driven by natural river erosion

and deposition processes.

4.2 Geomorphological Walkover

A detailed geomorphological walkover of the property was carried out on the 21 August 2016,

details of which are contained in our Initial Geotechnical Assessment Report (Appendix F).

Reference should be made to this report for the geomorphological description of the site. The

current investigation undertaken has not significantly changed or altered the outcome of the

geomorphological mapping, however, we have also included an assessment of the regional

geomorphology.



1 June 2018 4

5. FIELD EXPLORATION

To supplement our existing information for the site, and to develop a subsurface ground model,

twenty five hand auger boreholes and five machine boreholes were drilled, along with six CPT

probes at the site. The hand augers were drilled by Soil Investigations Ltd, and DCN Drilling Ltd

carried out the machine drilling and CPT probes at the approximate locations shown on the attached

Site Plan (Sheet 1).

5.1 Hand Auger Boreholes

Hand auger boreholes were drilled between 26 and 31 October 2016. The borehole locations were

selected to provide representative indications of the subsurface ground conditions across the site

where previous data was limited and to verify site conditions.

The boreholes were advanced using a 50mm diameter hand auger and were designated to be taken

to a depth of 5 metres or until effective refusal was reached, whichever being the shallower. Many

hand auger boreholes could not be advanced to 5m depth due to a dense material being

encountered as indicated in Table 6.1 in Section 6.0.

The subsurface conditions encountered at each borehole location were logged in general

accordance with ‘The guidelines for the classification and description of soil and rock for engineering

purposes’, December 2005 as outlined by the NZ Geotechnical Society.

A calibrated shear vane, used in accordance with New Zealand Geotechnical Society Guideline for

Hand Held Shear Vane Test, 2001 was used at regular depths of 0.5m in the drilled holes to

measure soil strengths, both in situ and remoulded. The vane shear strengths shown on the

attached logs have been corrected in terms of BS 1377:1990.

Scala penetrometer testing was subsequently undertaken through the base of each borehole with a

view to establishing a general indication of soil resistance for a further 2m beyond the base of each

borehole, or until effective refusal was encountered, whichever being encountered first. Effective

refusal was encountered within 2m below the base of all boreholes, with the exception of AH3, AH5,

AH6, AH7 and AH17. It should be noted that the results of this testing are indicative only and are

not to be used for any analytical purposes.



1 June 2018 5

The hand auger borehole logs and Scala penetrometer test results are presented on the attached

Sheets 4A to 4Y and 5A to 5D respectively.

5.2 Machine boreholes

Five machine boreholes, MH1 to MH5 were drilled at selected locations across the site. The

boreholes were advanced using both HQ open barrel and NQ size triple tube barrels, when

required. The drilling was supervised by a geologist from KGA, who logged and photographed the

core in general accordance with ‘The guidelines for the classification and description of soil and rock

for engineering purposes’, December 2005 as outlined by the NZ Geotechnical Society. Logs of the

machine boreholes and core photographs are presented as Sheets 6A to 6E.

On completion of the drilling, 32mm diameter piezometers (standpipes) were installed within all

machine boreholes with a response zone over the depths indicated in Table 1. A double standpipe

installation was carried out within borehole MH4 to provide additional groundwater data.

Table 1 - Standpipe Installation Details

Pipe Details(response

Zone)MH1 MH2 MH3 MH4 MH5

Standpipe 1 2 – 6m 2 – 6m 0.5 – 2.5m 9 – 11m 2 – 4m

Standpipe 2 N/A N/A N/A 14 – 16m N/A

The site was subsequently revisited to measure the level of standing groundwater after the effects of

drilling had dissipated. Details of groundwater monitoring are discussed further in Section 6.

5.3 CPT Probes

The CPT probes were carried out by DCN Drilling Ltd with the use of a Pagani rubber track mounted

remotely operated hydraulic rig. CPT probes were pushed until effective refusal was encountered.

CPT results are attached as Appendix C.



1 June 2018 6

6. SUBSURFACE CONDITIONS

Reference must be made to the attached borehole logs and CPT data presented in Appendix C for

more detailed descriptions of the strata underlying the site. It should be noted that whilst the

combined site investigation data provides a good indication of the soil properties across a site, it

must be accepted that subsurface conditions can and will vary away from the test positions in a way

that only becomes apparent at the time of construction. The subsurface ground conditions

encountered during this investigation are summarised below and in Table 2.

Topsoil

A surface veneer of topsoil up to 0.4m thick was encountered within all the boreholes. The topsoil

thickness was generally 0.2m in thickness.

Fill

Fill was encountered in boreholes AH8, AH9 and AH12. These boreholes were located central to

the site, near to disturbed ground from construction of access tracks and farm structures.

The fill material comprised variable strength and consistency silts and clays with intermixed

organics, topsoil and fine gravels. Vane shear strengths in the fill ranged from 68kPa to in excess of

104kPa. Based on this the fill is deemed to be non-engineered.

Alluvial Soils

Alluvial soils comprising silty clays and clayey silts and sands with localised intermixed organics

were identified underlying the topsoil/fill in the boreholes AH8, AH9 and AH24 drilled at the central

portion of the site, within the narrow gully areas. Vane shear strengths in the alluvial material

ranged from 19kPa to 68kPa. It is anticipated the extent of the soft alluvial material is localised in

extent within the gully features.

Northland Allochthon Group Soils

Soils interpreted to be Northland Allochthon Group soils were found in auger boreholes AH12 and

AH13 below topsoil and fill material to depths of 2.1m before it became to dense to hand auger. The

materials comprised generally of silts and clays with some friable materials logged. Vane shear

strengths ranged from 104kPa to UTP (unable to penetrate). These boreholes were situated close to

the existing farm track and the inferred Allochthon soils may comprise fill placed as part of the track

formation.



1 June 2018 7

Volcanic Soils

Volcanic soils comprising clays and silts were identified underlying topsoil in AH7, AH10 and AH11

to depths of up to 1.1m (AH10). Vane shear strengths ranged from 95kPa to 163kPa. The volcanic

soils were observed at the central portion of the site.

Colluvial soils / Firm to stiff residual soils

Soils determined to be colluvial in origin displayed similar material properties to those of the firm to

stiff Pakiri Formation soils. The materials comprised predominantly silts with varying clay and fine

sand content. These soils were observed in machine boreholes MH4 and MH5 and in hand auger

boreholes AH5, AH20, AH21 and AH22. Vane shear strengths in the colluvial material ranged from

18kPa to 199kPa. The colluvial materials are interpreted to make up the majority of the soils present

immediately downslope of the scarp feature at the northern central part of the site, and also the

upper soils of the steep sided valley features at the site.

Stiff to very stiff residual soils

Stiff to hard silts with varying clay and sand content were identified across the majority of the site

(AH1 to AH19, AH23 to AH25 and MH1). Vane shear strengths ranged from 48kPa to UTP.

Generally vane shear strengths were greater than 100kPa.

Inferred Dense material

The Scala penetrometer test results indicated effective refusal in boreholes AH4, AH8 to AH16, AH

18 to AH23 and AH25 at depths of between 1.15m (AH8) and 6.85m (AH21). The results indicate a

stiffer material underlies the site at these locations, which we have inferred to be ‘dense’ residual

oxidised layers of the underlying Waitemata Group material. Based on machine borehole data

adjacent to some of the hand auger boreholes the underlying Waitemata Group rock was found at

depths below the effective refusal found in the hand auger boreholes and therefore effective refusal

of the Scala probe cannot be used as an indication of rock head.

Waitemata Group Rock

Waitemata Group rocks were encountered in all machine boreholes (MH1-MH5). Depths to rock

(SPT N value >50) ranged from 2.3m (MH3) to 16.8m (MH4). The materials were generally

described as unweathered grey sandstone, occasionally interbedded with finer siltstones. MH1

encountered a 0.9m thick volcaniclastic submarine debris flow deposit from 6.2m depth. The

volcaniclastic was defined as matrix supported with sub-rounded to sub-angular clasts of siltstone.

The rock strengths were logged as very weak to moderately strong.



1 June 2018 8

Groundwater

Groundwater levels were recorded on the day of drilling, and upon periodic return visits which are

presented in Table 2. It must be acknowledged that the groundwater levels within the machine

boreholes were measured during a period when Auckland had higher than average seasonal

rainfall. However this may be higher groundwater levels are expected after periods of prolonged

rainfall and during the winter months.

Table 2 - Groundwater levels recorded in Machine Boreholes

HoleID

Groundwater measurements (m)

Depth toGroundwater

(m)Jan 2017Standpipe Fill / Topsoil Alluvium

Colluvium/volcanic/

firm to stiffresidual

soils

Stiff to verystiff residual

soils

Densematerial

(possiblebedrock)

MH11

0.2 1.1 6.2 From 6.2 4.22

MH2 2 0.2 1.05 6.3 From 6.3 5.5

MH31

0.2 1.5 2.3 From 2.3 1.2 (gully)2

MH41

0.2 16.4 From 16.4 8.42

m begl – metres below existing ground level *inferred from Scala penetrometer testing -not encountered

∆holes blocked ∆∆not located ^damp ┴ too dense to hand auger

7. MECHANISM OF SLOPE FAILURE

The site shows evidence of land slide movement, including a large scale feature to the east of the

site, beyond the property boundary.

Exposed rock outcrops were examined and these indicated a massive structure with no defined

bedding. Within the boreholes, the Waitemata Group rock was noted to be intact with sub horizontal

bedding. No defects associated with potential slip planes were identified within the rock encountered

in the machine boreholes or within the rock outcrops observed at the site. The depth of soil across

the site is variable with a relatively sudden transition from soil to rock. This suggests that the

underlying rock has not been sheared or deformed as in a deep seated block slide.

The soils were generally identified as Waitemata Group soils, with possible colluvium identified in

only three boreholes (MH2, MH5, AH5).



1 June 2018 9

The mechanism of the large scale feature to the east of the site is difficult to define. The site

walkover and subsurface investigation did not identify any evidence of movement within the rock

mass, indicating mass movement of the soil as the more likely mechanism. The watercourse is

meandering in a similar pattern both upstream and downstream of the site and observations indicate

that natural stream processes of erosion and deposition is occurring. The meandering of the

watercourse is likely the result of natural stream processes, however, we cannot exclude the

possibility that historical slope movement has not affected the stream alignment in the past.

The soils were generally identified as Waitemata Group soils, rather than colluvium which is

indicative of slope movement. It is possible that the large scarp feature identified to the east of the

site comprised a block type movement sliding over the rock, which has resulted in the soils retaining

its natural structure. Secondary, rotational failures have then occurred within the overlying soil

mantle, with high ground water levels a likely contributing factor.

8. LABORATORY TESTING

Two push tube samples and three core samples were taken from within the machine boreholes for

laboratory testing. The push tube samples were taken from machine boreholes MH4 and MH5, with

samples sent to Babbage Geotechnical Laboratory for consolidated undrained (CU), multi stage

triaxial shear strength testing. The three core samples were tested by OPUS Laboratory for

Unconfined Compressive Strength (UCS). The results obtained are summarised in Tables 3 and 4,

with laboratory reports attached as Appendix D and E respectively.



1 June 2018 10

Table 3 - CU Multi Stage test results

Cycle’s(effective

cellpressure)

MachineBorehole

GeologySample

LithologyDepth

(m)

Effective StressPath Parameters

CalculatedParameters from

Lab Results

Parametersadopted for

stability analysisfor Section 5

s’ (σ1’+ σ3’)/2

t’ (σ1’- σ3’)/2

C’(kPa)

ɸ’ (degrees)

C’(kPa)

ɸ’ (degrees)

100kPa MH4Pakiri Fm

Soils

SILT, fineto coarse

sandy.

9.0 –9.5

82 20

8.05 30.5 3 28

200kPa MH4Same as

above156 92

400kPa MH4Same as

above265 146

100kPa MH5Pakiri Fm

Soils /Colluvium

SILT, fineto coarse

sandy.

3.0 –3.5

103 53

200kPa MH5Same as

above184 99

400kPa MH5Same as

above314 162

Table 4 - UCS Summary of Test Results

Machine Hole Drill Core SizeSample

LithologyBulk Density

(t/m3)

Strain @Failure (%)

UCS MaxStress (MPa)

MH1 HQTT Sandstone 2.4 0.62 27



9. SLOPE STABILITY

The borehole information and site observations have been used to create the geological cross

sections presented as Sheets 3A to 3C. It should be noted that ground conditions shown on the

cross sections are inferred from the borehole points. Of the five cross sections, two are considered

to represent the critical cross sections requiring further slope stability analysis.



1 June 2018 11

The analyses were undertaken on Section 3-3 and Section 5-5’ under static and seismic conditions.

The analysis has been carried out for the proposed finished profile as presented on the drawings by

CCL. The locations of the cross sections are shown on the Site Plan. Details of the stability

analyses are contained in Appendix B.

The static slope stability analyses considered long and short term conditions assuming normal and

elevated groundwater levels, respectively. The maximum credible elevated ground water level is

assumed to be close to ground surface across the site.

Effective shear strength parameters were used for all the analyses and are based on laboratory test

results obtained during our investigation and our past experiences with similar soils in the wider

Auckland region. Table 5 displays the material properties used in the analyses.

Table 5 - Material Properties Used in Analysis

MaterialUnit Weight

(kN/m³)Effective stress

Cohesion c’ (kPa)

Effective StressAngle of internal

friction ϕ’ (°)

Proposed engineered fill 18 5 30

Inferred colluvium 18 2 24

Firm to stiff residual soil 18 3 28

Stiff to very stiff residual soil 18 5 30

Dense material / inferred bedrock 20 10 40

Seismic analyses were carried out using the pseudo static analysis method assuming a peak ground

acceleration of 0.12g, obtained using the guidelines in NZS1170 Part 5:2004, assuming a 150 year

earthquake event. The site has been classified as Class C.

Slope stability analyses were undertaken using the computer program SLIDE by Rocscience. The

Spencer method, a limit equilibrium method, was chosen using circular surfaces. Planar (block)

surfaces along the interface of the inferred rock and soil were also analysed, these returned higher

factor of safety values than the circular surfaces and therefore circular surfaces were adopted for

assessment purposes. The analyses indicate that the stability of the proposed finished profile has

acceptable factors of safety. A summary of the results of the stability analyses is given in Table 6.



1 June 2018 12

Table 6 - Result of Slope Stability Analysis

Cross Section Loading Condition

Factor of Safety

CalculatedMinimum Value

MinimumAcceptable*

Comment

5-5'

Long Term 1.6 1.5 OK

Short Term 1.3 1.3 OK

Seismic 1.2 1.2 OK

3-3’

Long Term 1.3 1.5See Section

9.5.2

Short Term 1.1 1.3See Section

9.5.2

Seismic 1.0 1.2See Section

9.5.2

* Factor of safety guidelines are according to Auckland Council ‘Code of Practice for Land Development and

Subdivision, Section 2 Earthworks and Geotechnical Requirements’ September 2013.

9.1 Relic Slopes

Evidence of shallow soil creep along the steeply sloping gullies (western boundary of Lots 42 to 46,

and along the southern gully slope south of Lots 41 and 42) at the site has been observed. Rock

has been mapped outcropping in the southern gully feature, adjacent to Lots 41 and 42.

Where the proposed road intersects and/or is adjacent to the steep ground, support should be

designed to minimise the risk of shallow instability undermining the road. Our initial test information

in this area indicates that the soil mantle on this portion of sloping ground is between 2m to 3m

deep. We recommend that further investigation is carried out in this area as part of the detailed

design process to confirm the ground conditions along the alignment of the road and to optimise the

design in these areas.

Similarly additional site investigation along sections of the road, (particularly near to where Section 3

is shown on Sheet 1) is recommended to confirm depth to rock and provide more optimised design

parameters for the retaining structures. Further details are addressed in Section 9.5.2.



1 June 2018 13

Observations during the geomorphological mapping exercise, and the borehole investigations, we

determine the slopes are currently stable, however adjacent Lots (Lots 40-46) will need building

platform setbacks applied to them.

10. GEOTECHNCIAL CONSIDERATIONS

The land is generally suitable for the proposed development provided the following geotechnical

considerations are undertaken and the earthworks are carried out in a controlled manner.

The following items have been addressed in further detail and should be considered in construction:

Bulk underfill drainage

Gully infill drainage

Relic steep slopes adjacent to proposed lot boundaries

Earthworks operations

Roading subgrades

Retaining structures

10.1 Underfill drainage

Underfill drains should be installed within the existing gullies where infrastructure or filling is to be

constructed, and any localised seepages identified during construction must be positively drained.

Indicative locations of these drains are shown on Sheet 2 attached; the final layout will depend on

site observations during earthworks.

10.1.1. Northern Instability Feature (Lots 17 to 27)

As stated in Section 6.0, it was found that a thickened colluvial soil layer is present within the

existing instability feature at the central northern part of the site, adjacent to the existing shed and

access track.



1 June 2018 14

Counterfort / subsoil drainage will be required to control groundwater levels to maintain slope

stability. The locations of all underfill and subsoil drains must be recorded on as-built plans by a

registered surveyor, which should be submitted as part of the completion documentation. These sub

fill drains will be required to be taken back into the existing slope beneath fill area, with drain depth

dependent on available fall to outlet. The drainage should be installed preferably along lot

boundaries where feasible.

The sub fill drains should have the following minimum design requirements:

2.0m in depth below the bottom of the fill level

A geotextile separation cloth, such as Bidim A19 geotextile or similar should be used to fully

wrap the drain.

Backfilled with drainage metal.

Minimum 0.6m in width.

A 160mm diameter Highways grade perforated drainage coil.

Minimum 1m clay capping layer.

We recommend the sub fill drains are taken up to the accessway between proposed Lot 12-13 and

Lots 17-18, where flushing points can be installed for necessary future maintenance.

10.1.2. Gully Infill Drainage

Gully infill drainage will be required along sections of the main road where the alignment is proposed

to traverse gully features. Subsoil drainage will be required to pick up the ground water and

discharge to the downslope side of the main road.

All drainage must be discharged in a controlled manner into a stormwater system or at engineer

designed outfall structures.

10.2 EARTHWORKS OPERATIONS

10.2.1. General

The bulk earthworks for the development will comprise of significant cut and filling operations to form

the building platforms and accessways. Generally, filling is to take place at the northern portion of

the site. Cutting of the head and upper portions of the landslip feature is proposed to create a

gentler sloping smooth profile in this area.



1 June 2018 15

Filling will be taking place at the toe of the steeply sloping ground within the gully feature and at the

downslope portion of the site which will generally enhance the slope stability in this area. Benching

of the existing ground is necessary prior to placement of fill.

Earthworks operations will need to be carefully planned due to the variable nature of the soils

present. All earthworks and drainage works are to be carried out in accordance with NZS4404:2010

– Land Development and Subdivision Infrastructure, NZS 4431:1989, Code of Practice for Earth Fill

for Residential Development and related documents and local standards. Provision should be made

for undercutting of any soft, weak or unsuitable materials found, especially at low-lying or gully

features.

10.2.2. Gully Materials

Our investigation has identified the presence of multiple gully features at the site. In the earthwork

areas where the main road is planned to traverse these gully features, soft organic gully soils have

been noted. These materials should be removed and replaced with suitably compacted clay or

hardfill to provide in the gully floors an appropriate base for benching and keying of fill to reduce

consolidation effects from fill surcharging and to maintain slope stability.

All gully areas will need to be inspected prior to placement of subsoil drainage and filling to ensure

soft or organic materials have been removed and effective drainage is installed.

10.2.3. Filling

Filling operations are understood to utilise mainly borrow material from the site, which will

predominantly comprise residual and colluvial soils. These soils should be suitable for placement

for fill provided they are conditioned to achieve optimum soil moisture levels.

Our experience of similar soils from nearby sites is that they require significant drying or conditioning

to enable placement as engineered fill. Cuts of up to 4m depth are proposed and may intercept

groundwater; materials sourced from these areas are likely to require a more intensive conditioning

process.

We recommend that following installation of underfill drainage, the proposed fill placement

commences at the base of the central northern sloping ground to provide toe support and reduce

the risk of inducing any slope movements.



1 June 2018 16

Drainage must be installed beneath the fill areas prior to the filling operations. All benching

operations should be in accordance with NZS4404:2010 and should be agreed with the earthworks

contractor to minimise the risk of potential stability issues.

A suitable location for any temporary stockpiles at the site should be subject to specific design to

minimise the potential for underlying soil movement.

Current Chester’s cut and fill drawings indicate up to 2.0m of fill is proposed to be placed in the

northwestern corner of the Lot, which is proposed to be retained. We recommend that no fill is

placed in the northwestern corner of Lot 42 due to loading of the steep gully slope below.

10.2.4. Excavation

Excavations for the proposed road alignment through the main gully area (central portion of the site

adjacent to Lots 33-37) are likely to intercept rock. From our borehole investigation the rock in this

area is noted to be generally moderately strong and relatively intact.

Excavatability of the rock should be confirmed; however it is envisaged to range from easy to hard

ripping rock in the upper residual to highly weathered rock. Based on the results from the UCS

testing in the unweathered Pakiri Formation rock, these rocks could be very difficult to excavate,

especially where the road alignment is cut into parts of the unweathered rock mass (adjacent to Lots

33 to 35), and rock breaking equipment may be required where the rock mass is relatively free from

defects/joint sets.

10.2.5. Pre-existing fill

Our investigation has identified the presence of existing (non-engineered) fill at the site (current

access tracks). During our investigation we located some gully muck material underneath a section

of fill (MH3). These materials are expected to be limited in lateral extent and should be removed

prior to filling and construction of the proposed road. Intermixed topsoil was identified through the

material, and a topsoil layer was identified at the interface between the fill and underlying alluvial

soils, where encountered. Based on this it is likely that the topsoil layer wasn’t stripped prior to the

placement of the fill. The depth of the fill was found to be approximately 1.3m (AH12) deep in

places.



1 June 2018 17

Complete undercutting of the fill should be achievable, as the extent of the fill is likely to be limited to

where the existing road traverses the gully areas. Due to the pastoral use of the land other areas of

non-engineered fill may be present at the site.

10.2.6. Batter Slopes

Permanent excavations in the natural soils should be formed to a general maximum slope gradient

of 1 vertical (V) on 4 horizontal (H) for cuts up to 3m high. Slopes that are steeper or higher than this

will be subject to specific engineering design. Drainage measures will be required where

groundwater or seepages are intercepted.

Provided sufficient planting and stormwater control is implemented, the batter face above the road

cutting along the main gully area can be formed at a maximum gradient of 1 vertical on 2 horizontal,

subject to observation of the face by a suitably qualified geotechnical engineer during construction.

Engineered fill batter slopes should be formed to a maximum slope gradient of 1V on 3H for fills up

to 4m high, fill slopes steeper or higher than this will be subject to specific engineering design and

will likely require geogrid reinforcing in the front face. This may affect batter slopes downslope of the

proposed road.

The proposed batter slope on the downslope edge of the main road (between Lots 27 and 28) over

the gully is shown to be at a slope gradient of 1 vertical on 3 horizontal. Provided the loose and

organic gully materials are removed to expose stiff to very stiff soils, and appropriate sub-soil

drainage is installed, the proposed batter slope should be suitable for design.

Temporary excavations should be limited to a maximum slope gradient of 1V on 1.5H for cuts up to

3m in height; beyond this specific design will be required.



1 June 2018 18

10.2.7. Compaction Control

Our recommended compaction control criterion for engineered fill is the minimum shear strength and

maximum air voids method as follows:

Air Voids Percentage

Structural Fill Average value of any 10 consecutive tests

not more than 10%

Maximum single value 12%

Vane shear strength (corrected)

Structural Fill Average value of any 10 consecutive tests

not less than 140kPa

Minimum single value 120kPa

10.3 Roading Subgrades

10.3.1. Main Road

The proposed main road is situated along portions of both proposed cut and filled ground. Based on

the results of our investigation and our experience of the soils in the area, a California Bearing Ratio

(CBR) of 2% is appropriate for preliminary design for the residual soils. Areas of fill may achieve

higher CBR values of up to 5%, however we recommend that penetration resistance and soaked

CBR testing be carried out on the subgrade to confirm the design values. Higher CBR values will be

present where road formation is into rock.

The road alignment through the main gully area (central to site) is to be formed upslope of and over

the existing track so that minimal fill is required on downslope edge. From our investigation,

relatively shallow, hard rock is present in this area. Excavations into rock may be hard digging.

Excavated rock faces should be free standing subject to inspection, but any soil mantle above will

need to be retained. We recommend further testing is carried out along the alignment at detailed

design stage to confirm rock / soil mantle depths to confirm retaining wall heights. The downslope

side of the road will either need to be filled and retained, or suspended. Consideration should be

made for any service trenches along parts of road which may be within the rock, as the rock will

prove difficult to trenching.



1 June 2018 19

10.3.2. Common Access

The common access at the central north of the site will be situated on weaker residual/colluvial soils.

To enhance stability in this area, re-contouring of the scarp feature by cutting into the upper part of

the slope and filling the downslope section to create a gentler smoothed profile (approx. 6°-8°) will

be undertaken enhancing the site stability.

10.4 Retaining Structures

10.4.1. General Retaining Comment

Retaining structures are indicated within the proposed development on the CCL Drawings. The

ground conditions across the site are variable in terms of soil strength and composition; therefore

different geotechnical design parameters for the walls are presented below:

Retaining walls with granular backfill being used behind may adopt effective stress shear strength

parameters of cohesion (c’) of 0kPa and an internal friction angle (Ø’) of 30° would be appropriate

for the retained soils. A coefficient of active earth pressure (KA) must be selected to reflect the

ground profiles above the walls and a minimum value of 0.4 is generally recommended.

With the exception of the retaining structures mentioned in Section 9.4.2 and 9.4.3, generally the

retaining structures may be designed for undrained shear strength of the founding soils of 75kPa. A

bulk unit weight of 18kN/m³ is appropriate for the backfill material.

Retaining walls constructed in areas of significant cut (particularly downslope of proposed Lots 2,

and 17 to 18) may encounter saturated sandy materials during construction. Provision to case the

holes during drilling should be considered.

10.4.2. Road Alignment Retaining Structures

Sheet 2 ‘Proposed Development Plan’ Indicates sections of the road where different retaining

structures may need to be used due to ground conditions.

The downslope edge of the road adjacent to Lot 42 has up to 1.0m of fill required to form subgrade

level, as shown on the CCL Proposed Cut and Fill Plan, drawing no: 210. This section of road may

be supported by either gravity wall or timber pole retaining wall structures.



1 June 2018 20

The final wall type will depend on subsurface conditions (limited subsurface information in this area).

Soil creep acting in the upper 2.0m on the slopes below the road will need to be considered in

design.

We recommend further investigation along critical sections of the road alignment at the detailed

design stage for confirmation of ground conditions, including soil creep and final retaining wall type.

10.4.3. Gravity Type Wall

Up to 4.0m of cut is proposed along a section of road as indicated on CCL Cut and Fill Plan

(drawing no: 210 appended). The proposed retaining wall is upslope of the main road, through the

central gully and adjacent to Lots 33 to 37 (shown on attached Sheet 2 as retaining wall Type 2).

Rock is observed to be outcropping along part of the existing farm track, indicating cuts for the

proposed main road will be into the underlying unweathered rock.

Retaining structures in this area should consist of gravity type walls to retain the upper soil mantle

overlying the unweathered rock, as it will be extremely difficult to auger into the underlying rock. The

gravity wall should be constructed with a minimum setback of 1.5m from the top of the rock face. An

ultimate unfactored bearing capacity for the foundation rock of 450kPa may be adopted in design.

The rock face may be left unsupported at a steep angle, provided that no adverse joint sets or

bedding planes are observed. Provisions for shotcreting and/or anchoring of the rock face should be

made if these rock defects are observed during excavation.

10.4.4. Timber Pole Retaining Wall Type

Proposed retaining wall structures are shown between Lots 1 and 2, Lots 17-18, Lots 19-22 and

along the eastern alignment of the accessway adjacent to Lots 33 - 36 (shown on attached Sheet 2

as retaining wall Type 1). These walls are shown to be between 1-2m of retained height. The ground

conditions indicate a pile type wall would be suitable for use in these locations such as a timber pole

retaining wall.

In ground support will be required to support the accessway to Lots 42-46 where it is located within

5m of the steep slopes. The support should be designed to accommodate up to 1.5m of potential

soil creep on the steeply sloping ground. Supports should be spaced at 3x pile diameter and taken

to found a minimum depth of 4m or 1m into the underlying rock.



1 June 2018 21

11. FINISHED BUILDING PLATFORMS

Provided the subdivision earthworks is carried out in accordance with the above recommendations,

NZS4431, NZS4404 and all local standards, the finished near level building platforms should be

suitable for construction of lightweight timber framed dwellings in accordance with NZS3604:2011.

From our experience of similar soils from nearby sites the expansive class of the near surface

natural soils is likely to fall within the range of moderately (Class M) to highly expansive (Class H2)

to AS2870. Expansive soil testing will need to be carried out as part of the geotechnical completion

report.

Lot specific restrictions will also be addressed in the geotechnical completion report, including but

not limited to, comment on allowable bearing capacities, the presence of retaining structures,

drainage easements, limits of cuts and fills, limits on development in relation to natural and batter

slopes.

Based on the information provided, Building Restriction Lines (BRL) will need to be defined at the

completion of the earthworks for the following Lots:

Lots 33 to 37

Lots 40 to 41

Lots 42 to 45

Any finished lot profiles which are moderately sloping will be subject to specific design in the

Completion Report due to sloping ground.

12. ENGINEERING OBSERVATIONS AND TESTING

The following observations are required by a suitably qualified geotechnical engineer / geologist

familiar with the contents of this report in order to prepare the required completion documentation for

the earthworks:

Subgrade soils and undercut excavations to confirm material type and suitability prior to any

filling or covering.

Subsurface drainage installation and extents.

Ground conditions within retaining structure foundation excavations.



1 June 2018 22

Fill placement including compaction control testing.

Observation of the main road excavations, particular attention will be needed to the exposed

rock and whether it displays adverse jointing or not.

Further site specific investigation will be required at the time of preparing the geotechnical

completion report for areas of the site that have been cut or not affected by the earthworks. It is

anticipated that hand auger boreholes will provide sufficient information for this.

13. LIMITATIONS

This report was prepared in the context defined in Section 1.0 above and must not be relied upon by

any other party other than that for whom it was prepared and the relevant Territorial Authority. It has

been compiled with respect to the brief given to us, and must not be relied upon in any other context

or recreated for any other purpose. Given the inherent variability of soils there may be conditions at

the site which have not been uncovered by this investigation.

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Vane ShearStrength (KPa)

Corrected(Per NZGS Guideline)

Geol

. Uni

t Field vane (peak)

50 100 150 Remoulded

Job No: Project:

Borehole Location:Surface Conditions:

Notes :

Shear Vane No. Drilled By Date Drilled Drill Method .......................

200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy

SAND CLAY SILT SILTclayey

ORGANICsoils

Dept

h (m

)

LithologicKeysee site plan

Hand Auger Soil Investigations LtdGeotechnical Soil Testing SpecialistsPH 021 627 709

Sheet 1 of 1

26th Oct 2016BM

AUGERHOLE LOG AH 1kga Geotechnical Ltd

Geovane1990

Gentle slope, Grass

223 Falls Rd, Warkworth

Note: Logged in accordance with 'The guidelines for the classification and description of soil and rock for engineering purposes' Dec 2005 as outlined by The NZ Geotechnical Society Inc. The subsurface data described above has been determined at this specific borehole location. Such data will not identify any variations away from this location . Plasticity referred to above is based on insitu moisture content on the day of testing .

J009585

113

49

104

52

159

73

122

70

107

43

162

95

92

43

73

28

110

37

92

34

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)

Shearvane Correction Value for Geovane1990is 1. 528 (calibrated 23/05/16)

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

End of Borehole 5.0m (Target Depth)

TOPSOIL

SILT, some clay, brownish orange, mottled brown, very stiff, moist, low plasticity

Reddish orange, mottled light grey

Trace of clay, trace of sand (fine), brownish grey, mottled orange, very stiff, moist, non plastic

Some clay, trace of sand (fine), brownish grey, very stiff, moist, low plasticity

Clayey, trace of sand (fine), grey, mottled orange, very stiff, moist, low to medium plasticity

Some clay, trace of sand (fine), brown, mottled grey, stiff, moist to wet, low plasticity

Occasional limonite gravels and staining

Trace of clay, trace of sand (fine), dark grey, mottled brown, very stiff, moist, non plastic

Stiff to very stiff, wet, dark grey

4A



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

26th Oct 2016BM


Geovane1946

Gentle slope, Grass

End of Borehole 3.1m (Too Dense to Auger)



J009585

86

33

89

15

208+

208+

UTP

UTP

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


Grou

ndw

ater

no

t E

ncou

nter

ed

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOILSILT, some clay, brown, very stiff, moist, low plasticity

CLAY, silty, light brown, mottled orange, stiff, moist, medium plasticity

Orange, mottled light brown, occasional limonite gravels and staining

SILT, some clay, orange, mottled light grey, very stiff, moist, low plasticity, frequent limonite gravels and staining

SILT, brownish orange, mottled light grey, very stiff, moist, non plastic, frequent limonite gravels and staining

Very stiff to hard, frequent weakly cemented clasts (1-2mm)

Common hard cemented clasts ( to 1mm)

4B



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

26th Oct 2016BM


Geovane1946

Gentle slope, Grass




J009585

107

48

80

18

89

18

48

15

86

21

110

27

164

80

134

42

140

62

143

48

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


Grou

ndw

ater

no

t E

ncou

nter

ed

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOILCLAY, silty, brownish orange, stiff to very stiff, moist, medium plasticity

Reddish orange

Stiff

SILT, some clay, reddish orange/orange, stiff, moist, low plasticity, frequent weakly cemented clasts (1-3mm)

SILT, reddish orange/orange, firm to stiff, moist, non plastic

Stiff, moist to wet, frequent weakly cemented clasts (1-3mm)

Very stiff

Some clay, reddish orange/orange, mottled light brown, frequent weakly cemented clasts (1-3mm)

Clayey, reddish orange, mottled light brown, very stiff, moist, low plasticity

4C



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

26th Oct 2016RF


DR 2053

Crest of steep slope, Grass


Shearvane Correction Value forDR 2053 is 1. 522 (calibrated 14/08/15)



J009585

169

37

188

35

108

21

93

29

172

38

UTP

195

35

207+

UTP

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)

Grou

ndw

ater

no

t E

ncou

nter

ed

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOILCLAY, silty, brownish orange, very stiff, moist, medium plasticity

SILT, some clay, reddish orange, very stiff, moist, low plasticity

Trace of sand (fine to medium), brownish orange/orange, very stiff, moist, non plastic, common weakly cemented clasts (1-2mm)

Stiff tto very stiff

Very stiff, grey, mottled dark orange, occasional lense of fine SAND

SAND (fine), silty, orange/dark orange, mottled grey, medium dense, moist, non plastic

SAND (fine), silty, brownish orange/orange, mottled grey, medium dense, moist, non plastic

SILT, trace of sand (fine to medium), brownish orange/orange, very stiff, moist, non plastic

4D



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

26th Oct 2016RF


DR 2053

Toe of steep slope, Bushclad





C O

L L

U V

I U M

J009585

80

6

65

5

18

3

UTP

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

NA

NA

NA

NA

TOPSOILSILT, clayey, brown, mottled orange and grey, stiff, sensitive, moist, low to medium plasticity, occasional intermixed friable SILT

CLAY, silty, brownish orange, stiff, sensitive, moist to wet, medium to high plasticity, frequent intermixed fine to medium sandy SILT

SILT, trace of clay, orange, very soft saturated, non plastic, common weakly cemented clasts (1-3mm)

Sandy (fine to medium), brownish orange, mottled grey, loose, saturated, frequent siltstone clasts (2-20mm)

SAND (fine to medium), grey, mottled orange, very loose, saturated, frequent siltstone clasts (2-20mm), poor sample recovery

SAND (fine to medium), silty, grey, dense, moist, non plastic

4E



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

26th Oct 2016VC


Geovane1990

Moderate slope, Grass




J009585

141

58

119

61

110

46

153

37

49

28

110

52

95

28

55

18

89

37

119

76

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOIL

CLAY, silty, brown, mottled orange, very stiff, moist, medium plasticity

High plasticity, reddish orange, mottled brown

SILT, clayey, light grey, mottled reddish brown, very stiff, moist, low plasticity, occasional weakly cemented clasts (2-5mm)

Some clay, reddish orange, firm to stiff, moist to wet, low plasticity

Free water encountered

Trace of clay, reddish brown, mottled orange, very stiff, moist, non plastic

SILT, reddish orange/orange, stiff, moist to wet, non plastic

Very stiff

4F



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

26th Oct 2016RF


DR 2053






J009585

163

65

132

59

110

29

99

27

113

29

134

35

94

34

89

29

73

35

85

37

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

) VO

LCAN

ICDE

POSI

TS

Grou

ndw

ater

no

t E

ncou

nter

ed

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOIL

CLAY, silty, brownish orange, very stiff, moist, medium plasticity

SILT, clayey, brownish orange, mottled red, very stiff, moist, low to medium plasticity

Some clay, pink, mottled light grey and orange, very stiff, moist, low plasticity, frequent weakly cemented clasts (2-5mm)

SILT, pink, mottled orange, stiff to very stiff, moist, non plastic, occasional lense of low plasticity SILT with some clay

Very stiff, trace of sand (fine), pink/purple

Stiff, pink, mottled light grey

Moist to wet, orange/dark orange, mottled light grey, occasional limonite gravels and staining

4G



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

26th Oct 2016RF


DR 2053

Watercourse





GUL

LYIN

WAS

H

J009585

24

5

UTP

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

) F

I L L

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOIL/SILT, with intermixed clayey SILT

SILT, clayey, brownish grey/grey, soft, moist to wet, low to medium plasticity

SILT, hard, moist, non plastic, dark orange limonite stained

4H



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

26th Oct 2016RF


DR 2053

Watercourse





G U

L L

Y

A L

L U

V I U

M

J009585

29

3

19

5

30

5

UTP

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

) IN

WAS

H /

FI

LL ?

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOIL/SILT

SILT, clayey, grey, mottled orange, soft to firm, wet, medium plasticity

CLAY, silty, grey, mottled orange, soft, saturated, high plasticity, frequent minor organic inclusions

Poor sample recovery

SILT, clayey, grey, stiff, saturated, low to medium plasticity

SILT, dark grey, hard, moist, non plastic

4I



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

26th Oct 2016BM


Geovane1946

Gentle slope, Grass




VOLC

ANIC

DE

POSI

TS

J009585

152

42

95

33

149

24

86

18

UTP

128

33UTP

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


Grou

ndw

ater

no

t E

ncou

nter

ed

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOILCLAY, silty, brownish orange, very stiff, moist, medium plasticity

SILT, some clay, brownish orange, very stiff, moist, low plasticity

Stiff to very stiff, light brown, frequent weakly cemented clasts (1-3mm)

SILT, some clay, orange, mottled light grey, very stiff, moist, low plasticity

SILT, orange, mottled light grey, very stiff, moist, non plastic

Brownish grey, mottled orange, common waekly cemented clasts (to 1mm)

Some clay, grey, mottled orange, stiff, moist, low plasticity, frequent weakly cemented clasts (1-5mm)

Trace of sand (fine), grey, very stiff, moist, non plastic

Some clay, grey, mottled orange, very stiff, moist, low plasticity

Trace of sand (fine), grey, hard, moist, non plastic

4J



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

26th Oct 2016VC


Geovane1990





J009585

119

58

141

89

119

34

153

83

150

49

128

55

UTP

214+

UTP

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

VOLC

ANIC

DE

POSI

TS

TOPSOIL


SILT, clayey, trace of sand (fine), brownish orange/orange, very stiff, moist, low to medium plasticity

Trace of clay, trace of sand (fine), light brown, mottled orange, very stiff, moist, non plastic

Light grey, mottled orange

Clayey, light grey, mottled orange, very stiff, moist, low to medium plasticity, occasional intermixed pockets of friable SILT

Moist to wet, orange, mottled light grey

SILT, orange, mottled grey, very stiff, moist, non plastic

Dark grey

4K



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

27th Oct 2016BM


Geovane1946





J009585

104

39

68

18

137

27

UTP

F I L

L


2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

NORT

HLAN

D A

LLOC

HTHO

N D

EPOS

ITS

?

SILT, dark brown, stiff to very stiff, moist, non plastic, frequent fine gravel inclusions

CLAY, silty, orange, brown, very stiff, moist, medium plasticity, occasional intermixed friable SILT, occasiobnal fine gravel inclusions

TOPSOIL, buried

SILT, some clay, dark brown, very stiff, moist, low plasticity with frequent intermixed dark greenish grey friable SILT

Very stiff to hardCLAY, silty, dark grey, mottled brown, very stiff, moist, medium plasticity with intermixed friable SILT, occasional fine gravels

Stiff, free water encountered

4L



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

27th Oct 2016BM


Geovane1946





J009585

104

28

UTP

NORT

HLAN

D A

LLOC

HTHO

N D

EPOS

ITS

?


2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOIL

SILT, some clay, dark brown, very stiff, moist, non plastic

CLAY, silty, orange, mottled brown, stiff to very stiff, moist, medium plasticity

SILT, trace of sand (fine)reddish brown, mottled orange and grey, very stiff, moist, non plastic

4M



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

27th Oct 2016VC


Geovane1990





J009585

95

34

128

86

95

24

122

49

180

31

76

34

214+

UTP

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOILCLAY, silty, orange, mottled brown, very stiff, moist, medium plasticity

SILT, clayey, orange, mottled brown, stiff to very stiff, moist, low to medium plasticity

CLAY, silty, light grey, mottled orange, very stiff, moist, medium plasticity

SILT, some clay, light grey, mottled orange, stiff, moist, low plasticity, occasional limonite gravels and staining

Trace of clay, orange, mottled light brown, very stiff, wet, non plastic, frequent limonite gravels and staining

Free water encountered

Clayey, brownish grey, mottled orange, stiff, moist to wet, lowto medium plasticity

Some clay, trace of sand (fine), very stiff, moist to wet, lowplasticity

Trace of clay, trace of sand (fine), dark grey, very stiff, moist, non plastic

4N



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

27th Oct 2016VC


Geovane1990

Gentle slope, Grass




J009585

134

43

144

61

134

73

150

61

119

49

159

73

79

37

141

89

43

18

46

24

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


Grou

ndw

ater

no

t E

ncou

nter

ed

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOIL

CLAY, silty, orange, mottledv brown, very stiff, moist, high plasticity

Orange, mottled light grey, frequent limonite gravels and staining

SILT, clayey, light grey, mottled orange, very stiff, moist, low to medium plasticity, occasional lense of light grey friable SILT

Some clay, light grey, mottled orange, very stiff, moist, low plasticity, frequent weakly cemented clasts (2-5mm)

Trace of clay, trace of sand (fine), light grey, stiff, moist, nonplastic

Moist to wet

4O



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

27th Oct 2016BM


Geovane1946

Moderate slope, Plant debris




J009585

134

57

86

48

54

21

59

12

68

18

86

15

UTP

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


Grou

ndw

ater

no

t E

ncou

nter

ed

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

131

24

TOPSOILSILT, some clay, dark brown, mottled orange, very stiff, moist, low plasticity

Brownish orange

CLAY, silty, orange, stiff, moist, medium plasticity

SILT, orange, mottled brown, very stiff, moist, non plastic

CLAY, silty, orange, stiff, moist, medium plasticity

SILT, some clay, trace of sand (fine), light brownish grey, mottled orange, stiff, moist to wet, low plasticity

Light brown

Wet, difficult sample recovery

Very stiff, orange, mottled light brownish grey

Very stiff to hard, brownish grey, mottled orange

4P



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

27th Oct 2016VC


Geovane1990





J009585

141

89

171

61

144

64

138

52

125

43

186

64

186

61

171

73

214+

214+

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


Grou

ndw

ater

no

t E

ncou

nter

ed

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOILCLAY, silty, orange, mottled brown, very stiff, moist, medium plasticity

Reddish orange/orange

SILT, some clay, reddish brown, mottled orange, very stiff, moist, low plasticity

Trace of clay, reddish brown, mottled orange, very stiff, moist, non plastic, occasional lense of medium plastic clayey SILT

Some clay, brownish grey/grey, very stiff, moist, low plasticity, occasional lense of medium plastic clayey SILT

Brownish grey, mottled orange, occasional weakly cemented clasts (2-5mm)

4Q



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

31st Oct 2016VC


Geovane1990

Flat, Grass




J009585

156

67

214+

153

79

171

73

104

46

122

58

83

40

110

55

UTP

UTP

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


Grou

ndw

ater

no

t E

ncou

nter

ed

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOIL

CLAY, silty, orange, mottled brown, very stiff, moist, medium plasticity

Reddish brown, mottled orange

SILT, clayey, reddish brown, mottled orange, very stiff, moist, low to medium plasticity, occasional lense of medium plastic clayey SILT

Orange, mottled brown

Some clay, orange, mottled brown, very stiff, moist, low plasticity, occasional weakly cemented clasts (2-5mm)

Stiff

Trace of clay, reddish brown, mottled light grey and orange, very stiff, moist, non plastic

4R



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

28th Oct 2016VC


Geovane1990

Flat, Grass




J009585

183

92

214+

153

73

125

67

122

34

134

43

159

58

141

73

199

43

156

55

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


Grou

ndw

ater

no

t E

ncou

nter

ed

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOIL


SILT, clayey, orange, mottled brown, very stiff, moist, low to medium plasticity, frequent weakly cemented clasts (to 1mm)

Some clay, reddish brown, mottled orange, very stiff, moist, low plasticity, frequent weakly cemented clasts (2-5mm)

Trace of clay, reddish brown, mottled orange, very stiff, moist, non plastic

No clay content, reddish orange/orange, mottled light grey, occasional lense of low to medium plastic clayey SILT

4S



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

28th Oct 2016VC


Geovane1990





J009585

199

122

180

79

138

28

119

40

122

40

125

52

83

34

UTP

UTP

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


Grou

ndw

ater

no

t E

ncou

nter

ed

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOIL


Reddish brown, mottled orange

SILT, clayey, reddish brown, mottled light grey, very stiff, moist, low to medium plasticity, frequent weakly cemented clasts (2-5mm)

Trace of clay, reddish orange, mottled light grey, very stiff, moist, non plastic, occasional weakly cemented clasts (2-5mm)

Light grey, mottled reddish orange, occasional lense of low to medium plastic clayey SILT

Clayey, reddish orange, mottled light grey, stiff, moist to wet, low to medium plasticity

Trace of clay, reddish orange, mottled light grey and pink, very stiff, moist, non plastic

4T



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

28th Oct 2016VC


Geovane1990

Steep slope, Grass




J009585

150

58

134

61

153

79

122

79

104

61

156

73

79

61

110

67

107

52

104

46

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOIL


SILT, clayey, orange, mottled brown, very stiff, moist, low to medium plasticity, occasional weakly cemented clasts (1-2mm)

SILT, clayey, orange, mottled brown, very stiff, moist, low to medium plasticity, occasional weakly cemented clasts (2-5mm)

Stiff to very stiff, occasional lense of medium plastic CLAY

Some clay, reddish brown, mottled orange, stiff to very stiff, moist, low plasticity, occasional weakly cemented clasts (2-5mm)

CLAY, silty, orange, mottled brown, very stiff, moist, medium plasticity, with intermixed friable SILT

4U



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

28th Oct 2016VC


Geovane1990





J009585

128

64

134

62

92

34

110

67

89

49

214+

165

40

141

104

196

67

98

34

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOIL


Reddish orange/orange

SILT, clayey, orange, mottled reddish brown, stiff to very stiff, moist, low to medium plasticity, occasional lense of friable SILT

Reddish orange, mottled light grey


CLAY, silty, light grey, mottled orange, very stiff, moist, medium to high plasticity

SILT, trace of clay, light grey, mottled orange, frequent limonite gravels and staining, very stiff, moist to wet, non plastic

Wet

4V



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

27th Oct 2016BM


Geovane1946





J009585

161

80

107

51

95

36

92

21

125

42

UTP

107

36

140

39

UTP

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


Grou

ndw

ater

no

t E

ncou

nter

ed

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOIL

SILT, some clay, brownish orange, very stiff, moist, low plasticity

Reddish orange, occasional weakly cemented clasts (1-5mm)

Trace of clay, reddish orange, mottled light grey and pink, stiff to very stiff, moist, non plastic

Pinkish red, mottled light grey and brown

Very stiff, frequent limonite staining

Grey, mottled orange and brown, common weakly cemented clasts (to 1mm)

Very stiff to hard, brownish grey, moist to wet, trace of sand (fine)

4W



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

26th Oct 2016BM


Geovane1946

Gentle slope, Water flow path




A L

L U

V I A

L

D

E P

O S

I T S

J009585

68

18

59

27

51

15

48

9

140

33

131

33

164

42

208+

208+

UTP

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOILSILT, dark brown, stiff, moist, non plastic

ORGANIC SILT, dark brown/black, stiff, moist, non plastic, frequent fine rootletsCLAY, silty, orange, mottled grey, stiff, moist, high plasticity

SILT, some clay, brown, mottled grey and orange, firm to stiff, wet, low plasticity, frequent decomposing wood inclusions

Moist to wet

CLAY, silty, grey, firm, saturated, high plasticity, frequent weakly cemented clasts (1-5mm), poor sample recovery

SILT, some clay, trace of sand (fine), dark greenish grey, mottled brown, very stiff, moist to wet, low plasticity


Grey, mottled orange

4X



Geol

. Uni

t Field vane (peak)


Job No: Project:


Notes :


200

Grou

ndw

ater

Prepared for:

........................

...................... ...........................

Dept

h (m

)

Grap

hic

Log

1

2

3

4

5

1

2

3

4

5

1

2

3

4

FILL TOPSOIL

SILTsandy


ORGANICsoils

Dept

h (m

)



Sheet 1 of 1

27th Oct 2016VC


Geovane1990

Flat, Grass




J009585

214+

UTP

UTP

W A

I T

E M

A T

A

G R

O U

P

S O

I L

S

( P

akiri

Fo

rmat

ion

)


Grou

ndw

ater

no

t E

ncou

nter

ed

2nd

Nov

embe

r 2

016

(day

of d

rillin

g)

TOPSOIL


SILT, some clay, brownish grey, mottled orange, very stiff, moist, low plasticity

SILT, brownish grey, hard, moist, non plastic

UTP

4Y

Scala Penetrometer Results - Blows Per 50mm Penetration

Soil Investigations LtdPO Box 47-559 Ponsonby Ph 021 627 709

Job Name: 223 Falls Rd, WarkworthJob No: J009585

Date: October, 2016Tested By: BM/VC

Augerhole No AH1 AH2 AH3 AH4 AH5 AH5 AH6 AH7Start Depth (m) 5.00m 3.10m 5.00m 4.40m 3.70m cont'd 5.00m 5.00m

50 25+ 1.5 8 16 4 1 sunk

100 1.5 6 12 5 1 0.5

150 sunk 2 6 5 7 1 0.5

200 3 11 3 1 1

250 1 2 25+ 6 1 1

300 1 2 6 1 2

350 2 3 4 1 2

400 1 3 3 2 2

450 2 4 2 2 1

500 1 4 3 2 2

550 2 4 3 2 2

600 2 4 3 1 2

650 2 4 4 2 3

700 3 3 5 2 3

750 2 3 3 2 4

800 3 2 5 2 4

850 3 2 15 3 3

900 4 2 12 3 4

950 3 2 6 3 5

1000 3 3 6 3 5

1050 3 3 9 3 5

1100 4 5 8 3 5

1150 3 6 8 4 4

1200 3 5 5 3 3

1250 4 3 6 3 4

1300 5 4 5 3 4

1350 19 4 3 3 4

1400 25+ 5 3 4 4

1450 7 4 3 5

1500 8 4 4 5

1550 8 4 4 6

1600 8 3 4 5

1650 5 4 4 6

1700 5 6 4 6

1750 4 6 5 7

1800 4 7 6 8

1850 5 7 8 8

1900 5

1950 5

2000 5

End Depth (m) 6.40m 3.15m 6.85m 4.65m 6.85m 6.85m 6.85m

5A





Augerhole No AH8 AH9 AH10 AH11 AH12 AH13 AH14 AH15Start Depth (m) 1.10m 2.10m 3.30m 4.40m 2.10m 1.10m 4.00m 5.00m

50 25+ 25+ 10 6 25+ 6 3 1

100 8 5 3 4 1

150 8 5 1 6 1

200 6 25+ 2 6 1

250 5 4 8 1

300 6 2 9 1

350 4 3 9 1

400 8 2 25+ 1

450 14 4 1

500 10 3 2

550 8 3 2

600 25+ 3 2

650 6 1

700 6 2

750 6 2

800 5 1

850 16 1

900 25+ 2

950 2

1000 3

1050 3

1100 5

1150 6

1200 4

1250 4

1300 4

1350 5

1400 6

1450 6

1500 8

1550 8

1600 6

1650 8

1700 12

1750 16

1800 25+

1850190019502000

End Depth (m) 1.15m 2.15m 3.90m 4.60m 2.15m 2.00m 4.40m 6.80m

5B





Augerhole No AH16 AH17 AH18 AH19 AH20 AH21 AH22 AH23Start Depth (m) 4.20m 5.00m 5.00m 5.00m 4.50m 5.00m 5.00m 4.50m

50 19 1 1 0.5 sunk 1 10

100 19 0.5 1 1 0.5 1 25+

150 12 0.5 1 0.5 1 1

200 8 1 1 2 0.5 2

250 8 0.5 1 1 1 1 3

300 8 0.5 2 2 1 1 3

350 25+ 0.5 1 2 1 2 3

400 0.5 2 2 2 2 4

450 1 2 3 2 2 4

500 1 4 3 3 3 5

550 1 3 2 3 3 5

600 2 3 3 4 3 4

650 2 4 2 4 3 5

700 4 5 2 5 2 5

750 4 4 4 5 3 6

800 4 4 3 6 3 5

850 3 5 3 6 4 5

900 3 6 3 5 4 6

950 4 6 4 5 4 6

1000 3 5 5 6 5 7

1050 3 8 5 6 5 6

1100 4 6 6 7 5 7

1150 3 7 6 7 6 7

1200 4 7 7 7 6 7

1250 3 6 7 8 7 8

1300 3 8 6 8 7 10

1350 3 8 6 10 6 10

1400 4 12 6 9 7 8

1450 4 10 8 8 7 12

1500 4 16 10 9 7 9

1550 5 25+ 13 9 6 9

1600 5 16 10 8 13

1650 6 25+ 10 10 16

1700 8 13 10 25+

1750 9 25+ 12

1800 10 10

1850 9 11

190019502000

End Depth (m) 4.55m 6.85m 6.55m 6.65m 6.25m 6.85m 6.70m 4.60m

5C





Augerhole No AH24 AH25Start Depth (m) 5.00m 1.80m

50 3 7

100 4 25+

150 4

200 4

250 4

300 3

350 2

400 1

450 3

500 2

550 5

600 4

650 5

700 4

750 7

800 6

850 6

900 7

950 9

1000 10

1050 9

1100 8

1150 10

1200 9

1250 12

1300 11

1350 8

1400 9

1450 8

1500 7

1550 12

1600 13

1650 12

1700 10

1750 13

1800 13

1850190019502000

End Depth (m) 6.80m 1.90m

5D

Ge

ne

rate

d b

y G

ER

OC

Co

re-G

S

Created: 23/03/2017 12:13:41 p.m.

Dep

th

Insta

llati

on

SP

T

MH1

PROJECT:

North Star Estates LTD

HOLE NO.:

CLIENT:

Geotechnical Investigation 9585

JOB NO.:

Meth

od

MACHINE BOREHOLE LOG

223 Falls Road, WarkworthSITE LOCATION:

CO-ORDINATES:

OPERATOR:RIG:

START DATE:

END DATE:

DATUM:

0mE, 0mN ()

DCNTractor

Ground Surface

12/12/2016

12/12/2016

TCR

(%)

RQD

(%)

25

50

75

25

50

75

Fra

ctu

re

Sp

acin

g(m

in/a

v/m

ax)

Gro

un

dW

ate

r

Sam

ple

Geo

log

ical

Un

it

Description

Gra

ph

ic L

og

Van

e S

hear

Str

en

gth

(k

Pa)

Topsoil with clayey silt and sand; dark brown. Firm, moist. Plant fibres/rootlets common. (TOPSOIL)

Sandy SILT with clay; brown. Stiff to very stiff, moist, moderate plasticity. Rootlets. (COLLUVIUM)

Silty CLAY with some sand; light brown. stiff to very stiff, moist, moderately to highly plastic.

Sandy SILTS with trace clay; mottled orange/pink/brown/cream. Firm to stiff, moist, no plasticity. Exhibits 'quick' behaviour in parts. Highly weathered transitional Pakiri formation? (WAITEMATA GROUP SOILS)

Unweathered grey CONGLOMERATE; moderately strong to strong. Matrix supported with rounded to sub-angular clasts of siltstone. (WAITEMATA GROUP - ROCK)

Unweathered grey SANDSTONE; moderately strong to strong.

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

N = 3

1, 0

0, 1

1, 1

N = 2

1, 0

0, 1

0, 1

N = 2

1, 1

0, 1

0, 1

N =

50

2, 5

50

N =

50

50

N =

50

50

RO

ISP

TR

OIS

PT

RO

ISP

TR

OIS

PT

RO

ISP

TR

OIS

PT

RO

3.5m - 6.2m: Oxidation/manganese oxide weathering along fractures

7.1m: Sub horizontal (~10 degrees) contact between conglomerate and the underlying sandstone.

21/0

3/2

017

13/1

2/2

016

14/1

2/2

016

T SC

OL

.W

AIT

EM

AT

A G

RO

UP

SO

ILS

WA

ITE

MA

TA

GR

OU

P -

RO

CK

10

06

01

00

10

01

00

10

01

00

10

01

00

10

09

2

92

93

67

10

0

96

196/43

119/61

82/46

61/7

125/20

UTP/-

Page 1 of 2

HOLE DEPTH: 10.65m

REMARKS

Notes & Abbreviations

Soils logged in accordance with 'The guidelines for the classification and description of soil and rock for engineering purposes' December 2005, NZGS

Water

Out Flow In Flow

Shear Vane

Corrected as per NZGS GuidelinesVane No.:1984UTP = Unable To Penetrate+ = Peak Exceeded- = No Result

Standing Water Level

Water Level At Time Of Drilling

6A

Ge

ne

rate

d b

y G

ER

OC

Co

re-G

S

Created: 23/03/2017 12:13:41 p.m.

Dep

th

Insta

llati

on

SP

T

MH1

PROJECT:


HOLE NO.:

CLIENT:


JOB NO.:

Meth

od



CO-ORDINATES:

OPERATOR:RIG:

START DATE:

END DATE:

DATUM:

0mE, 0mN ()

DCNTractor

Ground Surface

12/12/2016

12/12/2016

TCR

(%)

RQD

(%)

25

50

75

25

50

75

Fra

ctu

re

Sp

acin

g(m

in/a

v/m

ax)

Gro

un

dW

ate

r

Sam

ple

Geo

log

ical

Un

it

Description

Gra

ph

ic L

og

Van

e S

hear

Str

en

gth

(k

Pa)

Unweathered grey SANDSTONE; moderately strong to strong.

EOH: 10.65m

11.0

12.0

13.0

14.0

15.0

16.0

17.0

18.0

19.0

N =

50

50R

OIS

PT

WA

ITE

MA

TA

G

RO

UP

-

RO

CK

10

0

96

Page 2 of 2

HOLE DEPTH: 10.65m

REMARKS



Water

Out Flow In Flow

Shear Vane




17 February 2017 2

5.2m – 7.5m Tray 3 of 4

7.5 – 10.65m Tray 4 of 4

Ge

ne

rate

d b

y G

ER

OC

Co

re-G

S

Created: 8/03/2017 2:40:02 p.m.

Dep

th

Insta

llati

on

SP

T

MH2

PROJECT:


HOLE NO.:

CLIENT:


JOB NO.:

Meth

od



CO-ORDINATES:

OPERATOR:RIG:

START DATE:

END DATE:

DATUM:

0mE, 0mN ()

DCNTractor

Ground Surface

12/12/2016

13/12/2016

TCR

(%)

RQD

(%)

25

50

75

25

50

75

Fra

ctu

re

Sp

acin

g(m

in/a

v/m

ax)

Gro

un

dW

ate

r

Sam

ple

Geo

log

ical

Un

it

Description

Gra

ph

ic L

og

Van

e S

hear

Str

en

gth

(k

Pa)

Topsoil. (TOPSOIL)

Sandy SILT with trace clay; dark brown to brown. Stiff to very stiff, moist, low to no plasticity. (COLLUVIUM)

Sandy SILT; light brown, cream, orange mottling. Loose to moderately dense, moist, no plasticity. Remnant bedding/banding present. (WAITEMATA GROUP SOILS)

Silty SAND; reddy brown and orange and black. Loose becoming more dense, moist, no plasticity. Sub horizontal remnant bedding/banding.

SAND with silt; light brown and orange. Loose to dense, moist, no plasticity. Oxidised banding present. Sub-horizontal to sub-vertical bedding. (WAITEMATA GROUP - TRANSITIONAL)

SAND; orange and light grey. Medium dense to dense, moist, no plasticity.

Moderately weathered creamy brown SANDSTONE. Weak to moderately strong. Closely to moderately widely spaced fractures; moderate to sub-vertical oxidised fractures. (WAITEMATA GROUP - ROCK)Unweathered grey to dark grey SANDSTONE. Weak to strong. Gently to moderately inclined fractures. Moderately to widely spaced fractures. Oxidation/weathering has altered adjacent rock mass.

EOH: 9.03m

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

N = 2

1, 0

1, 0

0, 1

N =

22

2, 5

5, 7

5, 5

N =

10

2, 2

2, 3

2, 3

N =

50

4, 9

12, 38

N =

50

50

N =

50

50

RC

ISP

TR

CIS

PT

RC

ISP

TR

CIS

PT

RC

ISP

TR

CIS

PT

3.8m: Becoming to dense to drill open barrel.

5.1m - 5.3m: Very steeply inclined to sub-vertical laminated bedding

6.0m - 6.1m: Fine to medium grained gravels.

6.1m - 6.2m: sub horizontal laminated bedding

6.4m - 6.9m: Sub vertical and sub horizontal joints. oxidised on fractures. Undulating smooth to undulating rough.

7.1m: Very steeply inclined joint (~60 deg). Oxidised. Undulating rough.

T SC

OL

LU

VIU

MW

AIT

EM

AT

A G

RO

UP

SO

ILS

WA

ITE

MA

TA

GR

OU

P -

TR

AN

SIT

ION

AL

WA

ITE

MA

TA

GR

OU

P -

RO

CK

Gro

un

dw

ate

r N

ot

En

co

un

tere

d

10

01

00

10

01

00

48

10

01

00

10

01

00

100

92

20

10

0

70

168/15

122/15

92/27

UTP/-

Page 1 of 1

HOLE DEPTH: 9.03m

REMARKS



Water

Out Flow In Flow

Shear Vane




6B



MH2

0.0m – 3.0m Tray 1 of 3

3.0m – 6.3m Tray 2 of 3

17 February 2017 2

6.3m – 9.03m Tray 3 of 3

Ge

ne

rate

d b

y G

ER

OC

Co

re-G

S

Created: 23/03/2017 12:20:45 p.m.

Dep

th

Insta

llati

on

SP

T

MH3

PROJECT:


HOLE NO.:

CLIENT:


JOB NO.:

Meth

od



CO-ORDINATES:

OPERATOR:RIG:

START DATE:

END DATE:

DATUM:

0mE, 0mN ()

DCNTractor

Ground Surface

13/12/2016

13/12/2016

TCR

(%)

RQD

(%)

25

50

75

25

50

75

Fra

ctu

re

Sp

acin

g(m

in/a

v/m

ax)

Gro

un

dW

ate

r

Sam

ple

Geo

log

ical

Un

it

Description

Gra

ph

ic L

og

Van

e S

hear

Str

en

gth

(k

Pa)

Topsoil with gravel.

Organic clayey SILT; dark brown and dark grey. Soft to firm, moist to wet, low to moderate plasticity. Common brown and black coloured plant fibres. Becoming less organic rich towards base of the unit. (ALLUVIUM)

SAND with silt; light grey, becoming browny orange. Loose to dense, moist, no plasticity. (WAITEMATA GROUP SOILS)

SAND; dark grey. dense to very dense, moist, no plasticity.

Unweathered grey SANDSTONE. Moderately strong to strong. Laminated bedding of dark grey to black mudstone (carbonaceous) material. Fining upwards. Gently to moderately inclined bedding. (WAITEMATA GROUP - ROCK)

Unweathered grey SANDSTONE. Moderately strong to very strong.

Unweathered grey to dark grey SILTSTONE. Moderately strong to strong. Sub-horizontal bedding.

EOH: 6.03m

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

N = 3

0, 0

1, 0

1, 1

N =

50

50

N =

50

50

N =

50

50

RC

ISP

TR

CR

CR

CIS

PT

RC

ISP

TR

CIS

PT

5.4m: Very steeply inclined joint (~70 deg). Undulating smooth to undulating rough.

21/0

3/2

017

14/1

2/2

016

AL

LU

VIU

MW

AIT

EM

AT

A

GR

OU

P

SO

ILS

Mw

g-r

60

10

01

00

10

06

71

00

10

01

00

97

10

0

90

49/15

61/6

23/3

UTP/-

Page 1 of 1

HOLE DEPTH: 6.03m

REMARKS



Water

Out Flow In Flow

Shear Vane




6C



MH3

0.0m – 1.95m Tray 1 of 3

1.95m – 5.0m Tray 2 of 3

17 February 2017 2

5.0m – 6.03m Tray 3 of 3

Ge

ne

rate

d b

y G

ER

OC

Co

re-G

S

Created: 23/03/2017 12:21:13 p.m.

Dep

th

Insta

llati

on

SP

T

MH4

PROJECT:


HOLE NO.:

CLIENT:


JOB NO.:

Meth

od



CO-ORDINATES:

OPERATOR:RIG:

START DATE:

END DATE:

DATUM:

0mE, 0mN ()

DCNTractor

Ground Surface

13/12/2016

14/12/2016

TCR

(%)

RQD

(%)

25

50

75

25

50

75

Fra

ctu

re

Sp

acin

g(m

in/a

v/m

ax)

Gro

un

dW

ate

r

Sam

ple

Geo

log

ical

Un

it

Description

Gra

ph

ic L

og

Van

e S

hear

Str

en

gth

(k

Pa)

Gravel. (FILL)

CLAY with silt and minor sand; brown to dark orange with creamy and red mottling. Stiff to very stiff, moist, moderate to hhigh plasticity. (WAITEMATA GROUP SOILS)

SILT with sand and trace clay; dark red, brown and pink. Soft to stiff, moist to wet, no to minor plasticity. Common remnant sub horizontal bedding.

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

N = 4

1, 0

1, 1

1, 1

N = 4

1, 0

1, 1

1, 1

N = 2

1, 0

0, 1

0, 1

N = 4

1, 0

0, 1

1, 2

N = 4

1, 0

1, 0

1, 2

N = 4

1, 0

1, 1

1, 1

RC

ISP

TR

CIS

PT

RC

ISP

TR

CIS

PT

RC

ISP

TR

CD

PIS

PT

16/1

2/2

016

21/0

3/2

017

F IL LW

AIT

EM

AT

A G

RO

UP

SO

ILS

10

01

00

10

01

00

71

10

01

00

10

01

00

10

01

00

10

01

00

10

01

00

153/76

111/60

110/70

58/27

33/12

49/15

61/6

92/11

Page 1 of 2

HOLE DEPTH: 18.04m

REMARKS



Water

Out Flow In Flow

Shear Vane




Ge

ne

rate

d b

y G

ER

OC

Co

re-G

S

Created: 23/03/2017 12:21:14 p.m.

Dep

th

Insta

llati

on

SP

T

MH4

PROJECT:


HOLE NO.:

CLIENT:


JOB NO.:

Meth

od



CO-ORDINATES:

OPERATOR:RIG:

START DATE:

END DATE:

DATUM:

0mE, 0mN ()

DCNTractor

Ground Surface

13/12/2016

14/12/2016

TCR

(%)

RQD

(%)

25

50

75

25

50

75

Fra

ctu

re

Sp

acin

g(m

in/a

v/m

ax)

Gro

un

dW

ate

r

Sam

ple

Geo

log

ical

Un

it

Description

Gra

ph

ic L

og

Van

e S

hear

Str

en

gth

(k

Pa)

SILT with sand and trace clay; dark red, brown and pink. Soft to stiff, moist to wet, no to minor plasticity. Common remnant sub horizontal bedding.

SAND with silt; light brown, orange, pick. Loose, moist to wet, no plasticity. Oxidation/manganese staining common along bedding/joint planes.

Silty SAND; cream. Very loose to loose, moist to wet.

SAND with silt; dark orange and cream. moderate dense to dense, moist to wet, no plasticity, exhibits 'quick' behaviour in parts. Oxidation/manganese staining common along bedding/joint planes.

Highly weathered dark cream to light brown SANDSTONE. Very weak. (WAITEMATA GROUP ROCK)

Unweathered dark grey SANDSTONE. Moderately weak to hard. Moderately widely spaced fractures, gently to steeply inclined, undulating rough aperture. Oxidised on fracture surfaces.

EOH: 18.04m

11.0

12.0

13.0

14.0

15.0

16.0

17.0

18.0

19.0

N = 4

0, 1

0, 0

2, 2

N = 7

1, 0

0, 2

3, 2

N = 4

1, 0

0, 0

2, 2

N = 11

2, 2

2, 2

3, 4

N =

50

15, 50

N =

50

50

I S P T

RC

ISP

TR

CIS

PT

RC

ISP

TR

CIS

PT

RC

ISP

TR

CIS

PT

17.6m: Steeply inclined (~45 deg) joint. Some oxidation on fracture surface. Planar rough to undulating smooth.

WA

ITE

MA

TA

GR

OU

P S

OIL

SW

GR

10

01

00

10

01

00

10

01

00

10

01

00

10

01

00

75

35/3

29/3

119/6

UTP/-

Page 2 of 2

HOLE DEPTH: 18.04m

REMARKS



Water

Out Flow In Flow

Shear Vane






MH4

0.0m – 2.5m Tray 1 of 7

2.5m – 4.95m Tray 2 of 7

17 February 2017 2

4.95m – 7.5m Tray 3 of 7

7.5 – 10.95m Tray 4 of 7

geotechnical engineering investigation subdivision …... · accordance with ‘the guidelines for...

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