report to tkd architects on geotechnical … report presents the results of a geotechnical...

JK Geotechnics GEOTECHNICAL & ENVIRONMENTAL ENGINEERS

PO Box 976, North Ryde BC NSW 1670 Tel: 02 9888 5000 Fax: 02 9888 5003 www.jkgeotechnics.com.au

Jeffery & Katauskas Pty Ltd, trading as JK Geotechnics ABN 17 003 550 801

REPORT

TO

TKD ARCHITECTS

ON

GEOTECHNICAL INVESTIGATION

FOR

PROPOSED SCHOOL BUILDING

AT

HOMEBUSH WEST PUBLIC SCHOOL,

EXETER ROAD, HOMEBUSH WEST, NSW

23 December 2015

Ref: 28879ZHrpt

28879ZHrpt Page ii

Date: 23 December 2015 Report No: 28879ZHrpt Revision No: 0

Report prepared by: Adrian Hulskamp Senior Associate Geotechnical Engineer

Report reviewed by: Agi Zenon Principal Geotechnical Engineer For and on behalf of

JK GEOTECHNICS

PO Box 976

NORTH RYDE BC NSW 1670

Document Copyright of JK Geotechnics.

This Report (which includes all attachments and annexures) has been prepared by JK Geotechnics (JK) for its Client, and is intended for the use only by that Client. This Report has been prepared pursuant to a contract between JK and its Client and is therefore subject to:

a) JK’s proposal in respect of the work covered by the Report;

b) the limitations defined in the Client’s brief to JK;

c) the terms of contract between JK and the Client, including terms limiting the liability of JK.

If the Client, or any person, provides a copy of this Report to any third party, such third party must not rely on this Report, except with the express written consent of JK which, if given, will be deemed to be upon the same terms, conditions, restrictions and limitations as apply by virtue of (a), (b), and (c) above. Any third party who seeks to rely on this Report without the express written consent of JK does so entirely at their own risk and to the fullest extent permitted by law, JK accepts no liability whatsoever, in respect of any loss or damage suffered by any such third party.

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TABLE OF CONTENTS

1 INTRODUCTION 1

2 INVESTIGATION PROCEDURE 1

3 RESULTS OF THE INVESTIGATION 3

3.1 Site Observations 3

3.2 Subsurface Conditions 3

3.3 Laboratory Test Results 5

4 COMMENTS AND RECOMMENDATIONS 5

4.1 Earthworks 5

4.1.1 Site Preparation 5

4.1.2 Site Drainage 6

4.1.3 Subgrade Preparation 6

4.1.4 Engineered Fill 7

4.2 Retaining Walls 8

4.3 Footings 9

4.4 Earthquake Design Parameters 10

4.5 On-Grade Floor Slabs 10

4.6 External Pavements 11

4.7 Soil Aggression 12

4.8 Further Geotechnical Input 12

5 GENERAL COMMENTS 12

STS TABLE A: MOISTURE CONTENT, ATTERBERG LIMITS & LINEAR SHRINKAGE TEST REPORT

STS TABLE B: FOUR DAY SOAKED CALIFORNIA BEARING RATIO TEST REPORT

TABLE C: SUMMARY OF SOIL CHEMISTRY TEST RESULTS

BOREHOLE LOGS 1 TO 9 INCLUSIVE

DYNAMIC CONE PENETRATION TEST RESULTS (DCP 3)

FIGURE 1: BOREHOLE LOCATION PLAN

FIGURE 2 GRAPHICAL BOREHOLE SUMMARY

REPORT EXPLANATION NOTES

ENVIROLAB SERVICES REPORT NO: 139277

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1 INTRODUCTION

This report presents the results of a geotechnical investigation for the proposed school building at

Homebush West Public School, Exeter Road, Homebush West, NSW. The investigation was

commissioned by TKD Architects in an email, dated 27 October 2015. The commission was on the

basis of our proposal, Ref: ‘P41330ZH’, dated 12 October 2015.

Based on the supplied undated Woolacotts briefing letter (Reference: 15-196), we understand that

the project is at a concept stage and will include construction of a new on-grade two storey concrete

framed building, with column loads in the order of 1,000kN. The preliminary proposed building

footprint location is shown on the attached Figure 1, although the ground floor finished floor level

has not yet been finalised. However, for the purpose of this report, we assume that the proposed

ground floor level will be at, or close to, existing grade. External pavements will be constructed

around the proposed building.

The purpose of the investigation was to obtain geotechnical information on subsurface conditions

at nine nominated borehole locations, and based on the results obtained, to present our comments

and recommendations on earthworks, retaining walls, footings, on-grade floor slabs, external

pavements, earthquake design parameters and soil aggression.

We were also commissioned to carry out a Preliminary Environmental Site Assessment. This work

was carried out by EIS who prepared a report, Ref: E28879Krpt. This geotechnical report must be

read in conjunction with the EIS report.

2 INVESTIGATION PROCEDURE

Prior to the commencement of the fieldwork, a ‘Dial Before You Dig’ (DBYD) search was undertaken

and the borehole locations were electromagnetically scanned by a specialist sub-contractor for

buried services.

The fieldwork was carried out on 12 December 2015 and comprised the auger drilling of eight

boreholes (BH1, BH2 and BH4 to BH9) to depths of 4.5m below existing grade using our track

mounted JK308 drill rig. Where access for the drill rig was not possible, a ninth borehole (BH3)

was drilled to a refusal depth at 0.7m using a hand auger. A Dynamic Cone Penetration (DCP) test

(DCP2) was completed adjacent to BH2 to a depth at 1.4m. The borehole locations were drilled as

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close as practical to the nominated locations shown on the annotated aerial photograph attached

to the supplied Woolacotts briefing letter.

The borehole locations, which are shown on Figure 1, were set out by tape measurements off

existing surface features. The surface reduced levels (RLs) shown on the borehole logs and DCP

test results sheet were estimated by interpolation between spot levels shown on the supplied survey

plan and are therefore only approximate. The survey datum is the Australian Height Datum (AHD).

Figure 1 is based on the supplied survey plan (Drawing Number: 57737001A, dated 27 October

2015) prepared by Hill and Blume Pty Ltd.

The nature and composition of the subsurface soil and rock horizons were assessed by logging the

materials recovered during drilling. The relative compaction and strength of the subsoil profile was

assessed from the Standard Penetration Test (SPT) ‘N’ values and interpretation of the DCP test

results, augmented by hand penetrometer readings on samples obtained in the SPT split spon

sampler. The strength of the weathered bedrock profile was assessed by observation of auger

penetration resistance when using a tungsten carbide (TC) bit, together with examination of the

recovered rock cuttings and correlation with subsequent moisture content tests. We note that rock

strengths assessed in this way are approximate and variances in one order of rock strength should

not be unexpected. Groundwater observations were made in each borehole during the fieldwork.

Further details of the methods and procedures employed in the investigation are presented in the

attached Report Explanation Notes.

Our engineering geologist (Andrew Frost) was present on a full-time basis during the fieldwork to

set out the borehole locations, direct the electromagnetic scanning, nominate the testing and

sampling and prepare the attached borehole logs. The Report Explanation Notes define the logging

terms and symbols used.

Selected soil and rock cutting samples were returned to NATA registered laboratories (Soil Test

Services Pty Ltd [STS] and Envirolab Services Pty Ltd) for moisture content, Atterberg Limits, linear

shrinkage, soil pH, chloride and sulphate, Standard compaction and four day soaked CBR testing.

The test results are summarised in the attached Tables A, B and C. The Envirolab Services Pty

Ltd ‘Certificate of Analysis’ is attached to this report.

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3 RESULTS OF THE INVESTIGATION

3.1 Site Observations

Homebush West Public School (“the site”) is located in slightly undulating topography, near the

crest of a hill. The site was relatively flat, however, the north-eastern and south-eastern corners of

the site graded at about 3° to 4° down to the north-east and south-east, respectively. The site is

bound by Exeter Road to the north, Eastbound Road to the west and Tavistock Road to the south.

At the time of the fieldwork, the site was occupied by several one and two storey brick and

demountable school buildings, all of which appeared to be in good external conditions, based on a

cursory inspection. The ground surface surrounding the buildings was covered with grass, synthetic

grass, ‘soft fall’ and AC and concrete pavements. The AC pavement at the north-western corner

of the site was in poor condition, with cracks and depressions observed.

Several medium to large trees were present within the site, particularly along the site boundaries.

The neighbouring site to the east was occupied by two, three storey rendered apartment buildings,

which were set back about 3.5m from the common boundary. We were unable to assess if the

buildings contained a basement, due to a brick fence along the boundary. A three storey apartment

building was under construction just beyond the north-eastern corner of the site. There were

several rear yards located just off the northern end of the eastern site boundary.

Ground surface levels across the common boundaries were similar.

3.2 Subsurface Conditions

The 1:100,000 geological map of Sydney indicates the site is underlain by Bringelly Shale of the

Wianamatta Group.

Generally, the boreholes disclosed an asphaltic concrete (AC) pavement (BH7 only) and fill

overlying residual silty clay with weathered shale bedrock at shallow and moderate depth.

Reference should be made to the attached borehole logs and DCP test results for details at each

specific location. A graphical borehole summary is presented as Figure 2. A summary of the

encountered subsurface characteristics is presented below:

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Pavements

In BH7, a 40mm thick AC surfacing was encountered at the ground surface. A 360mm thick

granular roadbase layer was encountered below the AC surfacing.

Fill

Fill comprising sand, silty sand, silty clay and igneous gravel was encountered at the ground surface

in BH1 to BH6, BH8 and BH9 and below the AC pavement in BH7 and extended down to depths

between 0.3m (BH1, BH2 and BH3) and 0.95m (BH9) below existing grade. Inclusions of igneous,

sandstone and ironstone gravel, roots and root fibres were present within the fill. The fill in BH1

and BH2 was covered with synthetic grass and ‘soft fall’, respectively. The fill in BH8 and BH9 was

grass covered. The deeper fill in BH4 (0.9m), BH6 (0.7m), BH8 (0.7m) and 0.95m (BH9) was

assessed to be poorly and moderately compacted.

Residual Silty Clay

Residual silty clay of assessed high plasticity and stiff, very stiff and hard strength was encountered

below the fill in each borehole.

Hand auger refusal occurred within the residual silty clay profile in BH3. Assuming DCP3 extended

through similar residual soils below the hand auger refusal depth, very stiff to hard conditions are

indicated.

Weathered Shale Bedrock

Weathered shale bedrock was encountered in each rig borehole at depths between 0.9m (BH7)

and 2.4m (BH9) and extended down to the borehole termination depths. DCP3 is inferred to have

terminated with extremely weathered shale at 1.4m depth.

The shale bedrock profile ranged from extremely weathered and of extremely low strength to

distinctly and slightly weathered shale of low and medium strength. The upper more weathered

bedrock profile often contained low and medium strength iron indurated bands.

Groundwater

Each borehole was ‘dry’ during and on completion of drilling. We note that the groundwater levels

may not have stabilised within the short observation period. No long term groundwater monitoring

was carried out.

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3.3 Laboratory Test Results

The results of the moisture content tests carried out on recovered rock cutting samples generally

correlated well with our field assessment of bedrock strength, apart from the sample tested from

BH1 between 2.5 and 2.7m depth.

The Atterberg Limits and linear shrinkage test result confirmed the sample tested was of high

plasticity with a high potential for shrink-swell reactivity with changes in moisture content.

The four day soaked CBR test carried out on a sample of residual silty clay from BH4 resulted in a

value of 6% when compacted to 100% of Standard Maximum Dry Density (SMDD) and surcharged

with 9kg. The insitu moisture content of the sample was 1.1% ‘wet’ of the Standard Optimum

Moisture Content (SOMC).

The soil pH test results were 5.6 (BH1), 6.9 (BH7) and 5.6 (BH9) which show the samples tested

to be acidic. The sulphate and chloride test results were all less than or equal to 340mg/kg, which

indicates low sulphate and chloride contents.

4 COMMENTS AND RECOMMENDATIONS

4.1 Earthworks

All earthworks recommendations should be complemented by reference to AS3798-2007.

4.1.1 Site Preparation

Within the proposed development building footprint and following demolition of existing structures,

all trees (including their root balls) should be removed, and all grass, topsoil and root-affected soil

and any deleterious or contaminated existing fill should be stripped. Stripped topsoil, if present,

and root affected soils should be stockpiled separately as they are not suitable for reuse as

engineered fill. They may, however, be reused for landscaping purposes. Reference should be

made to the EIS report for guidance on the offsite disposal of soil.

We note that it is difficult to accurately assess the depth of topsoil and/or root affected soils in a

100mm diameter borehole. If considered to be an important contractual issue, we recommend that

a number of test pits be excavated across the proposed development footprint to more accurately

confirm the topsoil/root affected soil stripping depth. Alternatively, a geotechnical inspection could

be carried out after initial stripping to confirm the topsoil depth.

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Excavation down to design subgrade level, where required, may be completed using buckets fitted

to a hydraulic excavator.

4.1.2 Site Drainage

The clay subgrade at the site is expected to undergo substantial loss in strength when wet as

evident by the low CBR value. Furthermore, the clay subgrade is expected to have a high

shrink-swell reactive potential. Therefore, it is important to provide good and effective site drainage

both during construction and for long-term site maintenance. The principle aim of the drainage is

to promote run-off and reduce ponding. A poorly drained clay subgrade may become untraffickable

when wet. The earthworks should be carefully planned and scheduled to maintain good cross-falls

during construction.

4.1.3 Subgrade Preparation

Following site stripping and excavation down to design subgrade level, where required, we

recommend that the subgrade over the proposed building and pavement footprints be proof rolled

with at least six passes of a static smooth drum roller of at least 12 tonnes deadweight. The final

pass of proof rolling should be carried out under the direction of an experienced geotechnical

engineer for the detection of unstable or soft areas.

Subgrade heaving during proof-rolling may occur in areas where the clays have become ‘saturated’.

Heaving areas should be locally removed to a stable base and replaced with engineered fill, as

outlined below in Section 4.1.4.

If soil softening occurs after rainfall periods, then the clay subgrade should be over-excavated to

below the depth of moisture softening and replaced with engineered fill. If the clay subgrade

exhibits shrinkage cracking, then the surface should be watered and rolled until the shrinkage

cracks are no longer evident.

Engineered fill must be used where site levels need to be raised.

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4.1.4 Engineered Fill

Engineered fill comprising clayey soils should be compacted in maximum 200mm thick loose layers

to a density ratio between 98% and 102% of SMDD and at a moisture content within 2% of SOMC.

Engineered fill comprising well graded granular materials, such as imported crushed sandstone,

should be compacted in maximum 200mm thick loose layers to achieve a minimum density ratio of

at least 98% of SMDD.

The compaction specification may be relaxed to achieve a minimum density ratio of 95% of SMDD,

if the engineered fill is within grass or landscaped garden areas.

All engineered fill materials must be ‘clean’, free of organic matter and contain a maximum particle

size not exceeding 75mm.

All engineered fill should be either retained or, alternatively, battered to a permanent slope no

steeper than 1 Vertical (V) in 2 Horizontal (H). A flatter batter to 1V on 3H or even 1V on 4H may

be preferred in order to facilitate maintenance. All permanent fill batter slopes must be protected

from erosion by quickly establishing a vegetative cover, applying a reinforced shotcrete facing etc.

Where space permits, we recommend that engineered fill extend a horizontal distance of at least

1m beyond the design fill embankment slope so that adequate edge compaction can be achieved.

On completion of filling any excess fill can be trimmed off.

Backfilling of service trenches must also be carried out using engineered fill in order to reduce

post-construction settlements. Due to the reduced energy output of the rollers that can be placed

in trenches, backfilling should be carried out in 100mm thick loose layers and compacted using a

trench roller or a roller attachment fitted to an excavator. Due to the reduced loose layer thickness,

the maximum particle size of the backfill material should also reduce to 40mm. The compaction

specifications provided above are applicable, unless there is a stricter contract specification.

Density tests should be carried out on the engineered fill to confirm the above specification is

achieved. The frequency of density testing for engineered fill should be as per the requirements

outlined in Table 8.1 of AS3798. We recommend Level 2 control of fill compaction be adhered to

on this site. Due to a potential conflict of interest, the geotechnical testing authority (GTA) should

be directly engaged by TKD Architects (or their representative) and not by the earthworks contractor

or sub-contractors.

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We note that compaction of engineered fill behind retaining walls is very difficult. The use of a

single sized durable gravel, such as “blue metal” gravel or crushed concrete gravel (free of fines

and less than 10% brick), do not require significant compactive effort. Such material should be

nominally compacted using a hand operated vibrating plate (sled) compactor in 200mm thick loose

layers. A non-woven geotextile filter fabric such as Bidim A34 should be placed as a separation

layer immediately over the cut batter slope to control subsoil erosion. Provided the gravel backfill

is placed as recommended above, density testing of the gravel backfill would not be required. The

geotextile should then be wrapped over the surface of the gravel backfill and capped with at least

a 0.3m thick compacted layer of clayey engineered fill.

4.2 Retaining Walls

The major consideration in the selection of earth pressures for the design of retaining walls is the

need to limit deformations occurring outside the excavations. If retaining walls are proposed, the

following characteristic earth pressure coefficients and subsoil parameters may be adopted.

For allowable bearing pressure recommendations, refer to Section 4.3 below.

For free-standing cantilever walls which are retaining areas where minor movements can be

tolerated (i.e. landscaped or garden bed areas), a triangular lateral earth pressure distribution

may be adopted with an ‘active’ earth pressure coefficient, Ka, of 0.35, for the soil profile

assuming a horizontal backfill surface.

For cantilever walls where the tops are restrained by the permanent structure or which retain

areas where movements are to be reduced or for propped walls, a triangular lateral earth

pressure distribution should be adopted with an ‘at rest’ earth pressure coefficient, Ko, of 0.55,

for the soil profile assuming a horizontal backfill surface.

A bulk unit weight of 20kN/m3 should be adopted for the soil profile.

Any surcharge affecting the walls (eg. traffic loading, adjacent building footings, construction

loads, etc) should be taken into account in the wall design using the appropriate earth

pressure coefficient from above.

The retaining walls should be designed as drained and measures taken to provide complete

and permanent drainage of the ground behind the walls. Subsurface drains should

incorporate a non-woven geotextile fabric (eg. Bidim A34) to act as a filter against subsoil

erosion.

Lateral toe restraint may be achieved by suitably embedding the retaining wall footing to

sufficient depth. The embedment depth design should be based on a triangular lateral earth

pressure distribution and a ‘passive’ earth pressure coefficient, Kp, of 2.8, assuming horizontal

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ground in front of the wall. We note that significant movement is required in order to mobilise

the full passive pressure of a soil, and therefore a factor of safety of at least 2 should be

adopted to reduce such movements. Any localised excavations, such as for buried services,

in front of the walls should be taken into account in the embedment design. Alternatively,

lateral toe restraint may be achieved by keying the retaining wall into weathered shale

bedrock. An allowable lateral stress of 150kPa may be adopted for key design. Where there

is a change from founding in soil to rock, construction joints must be installed within the

retaining wall close to the change in founding conditions, so as to permit relative movements.

4.3 Footings

In BH9, sandy and clayey fill was encountered to 0.95m depth. No details on the existing fill (i.e.

placement method, compaction specification, density test records, etc.) have been provided to us

and therefore we assume that the existing fill is not a ‘controlled fill’ as outlined in Clause 1.7.13 of

AS2870-2011 “Residential slabs and Footings”. Therefore, the site as a whole is Class ‘P’. The

standard designs in AS2870 are not applicable for the proposed building and the footing system

design must be carried out using engineering principles.

The site is underlain by high plasticity residual silty clay. In BH9, the thickness of the soil profile

was 2.4m. Based on the laboratory test results, and thickness of the soil profile, we therefore expect

characteristic surface movements at this site to be in the Class ‘H1’ range (i.e. between 40mm and

60mm) in accordance with AS2870-2011.

Based on the supplied column loads, we recommend that the proposed building be uniformly

founded within the underlying weathered shale bedrock.

A combination of pad/strip footings and bored piles may be adopted. Bored piles will be required

where the bedrock is at least 1.5m below the proposed ground floor level.

Footings founded in weathered shale bedrock may be designed for a maximum allowable bearing

pressure of 700kPa. Footings founded into low strength or stronger shale bedrock may be designed

for a maximum allowable end bearing pressure of 1,000kPa, provided at least the initial footing

excavations/pile holes are inspected by a geotechnical engineer.

For bored piles, a maximum allowable shaft adhesion value (in compression) of 70kPa is applicable

within the weathered shale bedrock profile, below a minimum 0.3m length requirement. For tension

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piles, the above shaft adhesion value should be halved. The shaft adhesion through the soil profile

must be ignored due to strain incompatibility.

The provided design pressures are based upon serviceability criteria of deflections at the pile toe

of less than 1% of the pile diameter.

Retaining wall footings independent of the proposed building and founded in the underlying residual

silty clays of at least stiff strength may be designed for a maximum allowable end bearing pressure

of 100kPa.

All piles/footings should be drilled/excavated, cleaned out, inspected and poured with minimal

delay. If delays in pouring are envisaged, then we recommend that for pad/strip footings, a concrete

blinding layer be provided over the bases to reduce deterioration due to weathering.

We recommend that the ground beam between footings be poured over a void former at least 50mm

thick, so as to isolate the beams from the underlying clay soils.

4.4 Earthquake Design Parameters

Based on the investigation results and in accordance with AS1170.4–2007, a Hazard Factor (Z) of

0.08 is applicable for the site, together with a subsoil Class Be.

4.5 On-Grade Floor Slabs

Slab-on-grade construction is feasible for the proposed building provided the subgrade has been

prepared in accordance with recommendations described in Section 4.1.3 above. The design

parameters recommended in Section 4.6 below are appropriate.

The on-grade floor slab should be isolated from the walls, columns and footings of the proposed

building. Joints in the concrete on-grade floor slab should be designed to accommodate shear

forces but not bending moments by using dowelled or keyed joints.

There will be differential movements between the walls/columns and ground floor slab due to

shrink-swell of the underlying clay soils. Careful detailing between the floor slabs and

walls/columns will therefore be required. To reduce the effects of shrink-swell movements in the

underlying clays on the proposed building, we recommend that the external walls of the building be

protected with a perimeter apron slab at least 2m wide, which has at least a 0.7m deep beam below

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the outside edge of the slab and is graded away from the building. The gap between the building

and apron slab, as well as any transverse joints in the slab, must be appropriately sealed to prevent

water ingress.

4.6 External Pavements

Based on the investigation results, we recommend that the proposed pavements be designed on

the basis of a CBR value of 3% or a Short Term Young’s Modulus of 20MPa. This value is less

than the laboratory test result, however, we consider the CBR test was affected by the presence of

gravel within the sample.

The design subgrade CBR of 3% could be improved by the inclusion of a 0.3m thick (compacted)

select fill layer of CBR20% crushed sandstone which would increase the equivalent subgrade

design CBR value to 6%.

The select fill must comprise a well graded, granular crushed sandstone (maximum particle size

not exceeding 75mm) with a soaked CBR value of at least 20%. If the available sandstone is

assessed by tactile examination or laboratory testing to be a borderline material (ie. achieving a

CBR value of just over 20% at a compaction density ratio of 100% of SMDD), then we expect that

it will break down and degrade during compaction with a heavy roller to a material with an ‘insitu’

CBR value less than 20%. As such, we recommend that the CBR testing allow for the degradation

of the crushed sandstone. The standardised RTA Specification T102 method, which attempts to

replicate the degradation process by pre-treatment of the crushed sandstone with 3 cycles of

repeated compaction, would be appropriate. All crushed sandstone select fill should be compacted

in maximum 200mm thick loose layers to at least 100% of SMDD.

We recommend that all base course materials comprise DGB20 in accordance with RMA

Specification D&C 3051 unbound base. The DGB20 material should be compacted in maximum

200mm thick loose layers using a large smooth drum roller to at least 98% of Modified Maximum

Dry Density (MMDD). We recommend that all sub-base materials comprise DGS40 in accordance

with RMA Specification D&C 3051 unbound sub-base. The DGS40 material should be compacted

in maximum 200mm thick loose layers using a large smooth drum roller to at least 95% of MMDD.

Adequate moisture conditioning to within 2% of Modified Optimum Moisture Content (MOMC)

should be provided during placement so as to reduce the potential for material breakdown during

compaction.

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Density tests should be regularly carried out on the granular pavement materials to confirm the

above specifications are achieved. The frequency of density testing should be as per the

requirements outlined in Table 8.1 of AS3798. Level 2 testing of fill compaction is the minimum

permissible in AS3798-2007. The GTA should be directly engaged by TKD Architects (or their

representative) and not by the earthworks contractor or sub-contractors.

Subsoil drains should be provided below the edges of the proposed pavements with invert levels

at least 200mm below design subgrade level. The drainage trenches should be excavated with a

uniform longitudinal fall to appropriate discharge points so as to reduce the risk of water ponding.

The subgrade should be graded to promote water flow towards the subsoil drains. Discharge from

the subsoil drains should be piped to the stormwater system.

4.7 Soil Aggression

Based on the soil chemistry test results, a ‘non-aggressive’ exposure classification for concrete is

applicable in accordance with Table 6.4.2 (C) in AS2159-2009.

4.8 Further Geotechnical Input

We summarise below the recommended additional geotechnical input that needs to be carried out:

Topsoil inspection, if appropriate.

Geotechnical inspection of footing excavations/pile holes.

Proof rolling inspections.

Additional CBR testing, if appropriate.

Density testing of all engineered fill, sub-base and base course materials.

5 GENERAL COMMENTS

The recommendations presented in this report include specific issues to be addressed during the

construction phase of the project. As an example, special treatment of soft spots may be required

as a result of their discovery during proof-rolling, etc. In the event that any of the construction phase

recommendations presented in this report are not implemented, the general recommendations may

become inapplicable and JK Geotechnics accept no responsibility whatsoever for the performance

of the structure where recommendations are not implemented in full and properly tested, inspected

and documented.

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The long term successful performance of floor slabs and pavements is dependent on the

satisfactory completion of the earthworks. In order to achieve this, the quality assurance program

should not be limited to routine compaction density testing only. Other critical factors associated

with the earthworks may include subgrade preparation, selection of fill materials, control of moisture

content and drainage, etc. The satisfactory control and assessment of these items may require

judgment from an experienced engineer. Such judgment often cannot be made by a technician

who may not have formal engineering qualifications and experience. In order to identify potential

problems, we recommend that a pre-construction meeting be held so that all parties involved

understand the earthworks requirements and potential difficulties. This meeting should clearly

define the lines of communication and responsibility.

Occasionally, the subsurface conditions between the completed boreholes may be found to be

different (or may be interpreted to be different) from those expected. Variation can also occur with

groundwater conditions, especially after climatic changes. If such differences appear to exist, we

recommend that you immediately contact this office.

This report provides advice on geotechnical aspects for the proposed civil and structural design.

As part of the documentation stage of this project, Contract Documents and Specifications may be

prepared based on our report. However, there may be design features we are not aware of or have

not commented on for a variety of reasons. The designers should satisfy themselves that all the

necessary advice has been obtained. If required, we could be commissioned to review the

geotechnical aspects of contract documents to confirm the intent of our recommendations has been

correctly implemented.

A waste classification will need to be assigned to any soil excavated from the site prior to offsite

disposal. Subject to the appropriate testing, material can be classified as Virgin Excavated Natural

Material (VENM), General Solid, Restricted Solid or Hazardous Waste. If the natural soil has been

stockpiled, classification of this soil as Excavated Natural Material (ENM) can also be undertaken,

if requested. However, the criteria for ENM are more stringent and the cost associated with

attempting to meet these criteria may be significant. Analysis takes seven to 10 working days to

complete, therefore, an adequate allowance should be included in the construction program unless

testing is completed prior to construction. If contamination is encountered, then substantial further

testing (and associated delays) should be expected. We strongly recommend that this issue is

addressed prior to the commencement of excavation on site.

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This report has been prepared for the particular project described and no responsibility is accepted

for the use of any part of this report in any other context or for any other purpose. If there is any

change in the proposed development described in this report then all recommendations should be

reviewed. Copyright in this report is the property of JK Geotechnics. We have used a degree of

care, skill and diligence normally exercised by consulting engineers in similar circumstances and

locality. No other warranty expressed or implied is made or intended. Subject to payment of all

fees due for the investigation, the client alone shall have a licence to use this report. The report

shall not be reproduced except in full.

Reference No: 28879ZH

Project: Proposed School Building

Borehole Sample Depth Sample Description pH Sulphate Chloride

Number (m) Units (mg/kg) (mg/kg)

BH1 0.7 - 0.95 Residual SILTY CLAY 5.6 200 56

BH7 0.7 - 0.9 Residual SILTY CLAY 6.9 340 200

BH9 0.5 - 0.95 FILL Silty Clay 5.6 56 <10

TABLE C

SUMMARY OF SOIL CHEMISTRY TEST RESULTS

SOIL pH, SULPHATE AND CHLORIDE

0

1

2

3

4

5

6

7

DRY ONCOMPLET-

ION

N = 82,2,6

N = 183,7,11

CH

-

FILL: Sand, fine to medium grained,brown.FILL: Silty clay, low to mediumplasticity, brown, trace of fine grainedigneous gravel.SILTY CLAY: high plasticity, greymottled red brown, trace of finegrained ironstone gravel.

SHALE: grey and red brown.

as above,but grey and dark grey.

END OF BOREHOLE AT 4.5m

DM

MC>PL

XW

DW

SW

VSt

H

EL

VL

M

200260230

420430400

SYNTHETIC GRASSSURFACING

RESIDUAL

VERY LOW 'TC' BITRESISTANCE

LOW RESISTANCE

LOW TO MODERATERESISTANCE

JK GeotechnicsGEOTECHNICAL AND ENVIRONMENTAL ENGINEERS

BOREHOLE LOGBorehole No.

1

Client: TKD ARCHITECTS

Project: PROPOSED SCHOOL BUILDING

Location: EXETER ROAD, HOMEBUSH WEST, NSW

Job No. 28879ZH Method: SPIRAL AUGERJK308

R.L. Surface: » 27.1m

Date: 12-12-15 Datum: AHD

Logged/Checked by: A.F./A.J.H.

Gro

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ecord

ES

SA

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50

DB

DS

Fie

ld T

ests

Depth

(m

)

Gra

phic

Log

Unifie

dC

lassific

ation

DESCRIPTION

Mois

ture

Conditio

n/

Weath

eri

ng

Str

ength

/R

el. D

ensity

Hand

Penetr

om

ete

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eadin

gs (

kP

a.)

Remarks

CO

PY

RIG

HT

1/1

0

1

2

3

4

5

6

7

DRY ONCOMPLET-

ION

N = 41,2,2

N = 152,6,9

CH

-

FILL: Igneous gravel, fine to mediumgrained, grey.

SILTY CLAY: high plasticity, greymottled red brown, trace of fine tomedium grained ironstone gravel.

as above,but with fine to medium grainedironstone gravel.SHALE: grey brown.



D

MC>PL

MC»PL

XW

DW

SW

St

H

EL

VL

L

160160160

420480460

'SOFTFALL'SURFACING

RESIDUAL

VERY LOW'TC' BITRESISTANCE

LOW RESISTANCE



2








Gro

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rR

ecord

ES

SA

MP

LE

SU

50

DB

DS

Fie

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ests

Depth

(m

)

Gra

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Log

Unifie

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lassific

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DESCRIPTION

Mois

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Conditio

n/

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ng

Str

ength

/R

el. D

ensity

Hand

Penetr

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kP

a.)

Remarks

CO

PY

RIG

HT

1/1

0

1

2

3

4

5

6

7

DRY ONCOMPLET-

ION

REFER TODCP TESTRESULTS CL-CH

FILL: Silty sand, fine to coarsegrained, trace of root fibres and fine tocoarse grained igneous gravel.SILTY CLAY: medium to highplasticity, grey brown.


D

MC<PL (VSt-H)

(H)

RESIDUAL

HAND AUGERREFUSAL IN HARDCLAY



3




Job No. 28879ZH Method: HAND AUGER R.L. Surface: » 26.3m


Logged/Checked by: A.F./

Gro

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50

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DS

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Depth

(m

)

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Log

Unifie

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DESCRIPTION

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Conditio

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/R

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Hand

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kP

a.)

Remarks

CO

PY

RIG

HT

1/1

0

1

2

3

4

5

6

7

DRY ONCOMPLET-

ION

N = 62,2,4

N = 82,4,4

CH

-

FILL: Silty sand, fine to mediumgrained, brown, trace of ash, rootsand root fibres and fine to coarsegrained ironstone gravel.

SILTY CLAY: high plasticity, greybrown.

SHALE: grey brown.



M

MC>PL

XW

DW

SW

VSt

EL

L

M

330300

290300310

APPEARSPOORLYCOMPACTED

RESIDUAL

VERY LOW 'TC' BITRESISTANCELOWRESISTANCE

MODERATERESISTANCE



4








Gro

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50

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DS

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Depth

(m

)

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Unifie

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DESCRIPTION

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Hand

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a.)

Remarks

CO

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RIG

HT

1/1

0

1

2

3

4

5

6

7

DRY ONCOMPLET-

ION

N = 187,9,9

CH

-

FILL: Silty clay, low plasticity, brown,trace of fine to medium grainedironstone and igneous gravel.SILTY CLAY: high plasticity, greybrown, trace of fine to medium grainedironstone gravel.

SHALE: grey brown, with L-M strengthiron indurated bands.

SHALE: grey and dark grey.


MC<PL

MC<PL

XW-DW

DW

H

EL-VL

L

>600>600>600

RESIDUAL

VERY LOW'TC' BITRESISTANCEWITH LOW BANDS

LOW RESISTANCE



5








Gro

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Depth

(m

)

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Unifie

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DESCRIPTION

Mois

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Conditio

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Hand

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Remarks

CO

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RIG

HT

1/1

0

1

2

3

4

5

6

7

DRY ONCOMPLET-

ION

N = 64,3,3

N = 162,4,12

CH

-

FILL: Silty clay, low to mediumplasticity, brown, trace of fine tocoarse grained sandstone andigneous gravel.

SILTY CLAY: high plasticity, greymottled red and orange brown, traceof fine to medium grained ironstonegravel.

SHALE: grey brown, with L-M strengthiron indurated bands.



MC<PL

MC>PL

XW

DW

VSt

EL

VL

L-M

300320300

300290320

APPEARS POORLYCOMPACTED

RESIDUAL

VERY LOW'TC' BITRESISTANCE WITHLOW BANDS

LOW RESISTANCE



6








Gro

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1/1

0

1

2

3

4

5

6

7

DRY ONCOMPLET-

ION

N = 72,2,5

N > 1012,10/50mm

REFUSAL

CH

-

ASPHALTIC CONCRETE: 40mm.tFILL: Igneous gravel, fine to coarsegrained, red brown and grey, with fineto coarse grained sand.SILTY CLAY: high plasticity, greybrown, trace of fine to medium grainedironstone gravel.SHALE: grey brown mottled redbrown.



M

MC»PL

XW

DW

VSt

EL

VL

L

330360390

RESIDUAL

VERY LOW'TC' BITRESISTANCE

LOW RESISTANCE



7








Gro

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50

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Depth

(m

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1/1

0

1

2

3

4

5

6

7

DRY ONCOMPLET-

ION

N = 62,2,4

N > 156,15/

150mmREFUSAL

CH

-

FILL: Silty clay, medium plasticity,brown, trace of igneous gravel andfine to medium grained sand.

SILTY CLAY: high plasticity, greybrown, trace of fine grained ironstonegravel.

SHALE: red brown and grey brown,with L-M strength iron induratedbands.



MC<PL

MC>PL

XW

DW

VSt

EL

VL

L

240300340

GRASS COVER

APPEARSPOORLYCOMPACTED

RESIDUAL

VERY LOW 'TC' BITRESISTANCE WITHLOW BANDS

LOW RESISTANCE



8








Gro

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1/1

0

1

2

3

4

5

6

7

DRY ONCOMPLET-

ION

N = 92,5,4

N = 103,4,6

CH

-

FILL: Silty sand, fine to mediumgrained, brown, trace of roots, rootfibres and fine to medium grainedigneous gravel.FILL: Silty clay, medium to highplasticity, orange brown, trace of ashand fine grained ironstone gravel.

SILTY CLAY: high plasticity, greymottled grey brown.

SHALE: grey brown, with M strengthiron indurated bands.



D

MC»PL

MC>PL

XW

DW

SW

VSt

EL

VL-L

L-M

310330360

GRASS COVER

APPEARSMODERATELYCOMPACTED

RESIDUAL

VERY LOW 'TC' BITRESISTANCE WITHMODERATE BANDS

LOW RESISTANCE

MODERATERESISTANCE



9








Gro

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1/1


DYNAMIC CONE PENETRATION TEST RESULTS




Job No. 28879ZH Hammer Weight & Drop: 9kg/510mm

Date: 12-12-15 Rod Diameter: 16mm

Tested By: A.F. Point Diameter: 20mm

Number of Blows per 100mm Penetration

Test Location RL ~26.3m

Depth (mm) 30 - 100 SUNK

100 - 200 5

200 - 300 9

300 - 400 10

400 - 500 12

500 - 600 7

600 - 700 7

700 - 800 6

800 - 900 8

900 - 1000 8

1000 - 1100 15

1100 - 1200 18

1200 - 1300 20

1300 - 1400 24

1400 - 1500 END

1500 - 1600

1600 - 1700

1700 - 1800

1800 - 1900

1900 - 2000

2000 - 2100

2100 - 2200

2200 - 2300

2300 - 2400

2400 - 2500

2500 - 2600

2600 - 2700

2700 - 2800

2800 - 2900

2900 - 3000Remarks: 1. The procedure used for this test is similar to that described in AS1289.6.3.2-1997, Method 6.3.2.

2. Usually 8 blows per 20mm is taken as refusal3. Survey datum is AHD.

Ref: JK Geotechnics DCP 0-3m July 2012

COPYRIGHT

6N =6

N =16

7N =7

N =>10

8N =6

N =>15

5N =18

9N =9

N =10

2N =4

N =15

4N =6

N =8

31

N =8

N =18

30

28

26

24

22

20

18

R.L

. (m

)

30

28

26

24

22

20

18

R.L

. (m)

GRAPHICAL BOREHOLE SUMMARY

Fill

Silty Clay

Shale

Asphaltic/BituminousPaving orCoal

N SPT "N"VALUE

Nc SOLID CONEBLOWCOUNTSPER 150mm

Scale: 1 : 100 (vert) ; NTS (horiz)

JK Geotechnics

NOTE: REFER TO BOREHOLE LOGS Job No.: 28879ZH Figure No.: 2

Jeffery & Katauskas Pty Ltd, trading as JK Geotechnics ABN 17 003 550 801

JKG Report Explanation Notes Rev2 May 2013 Page 1 of 4

REPORT EXPLANATION NOTES

INTRODUCTION

These notes have been provided to amplify the geotechnicalreport in regard to classification methods, field proceduresand certain matters relating to the Comments andRecommendations section. Not all notes are necessarilyrelevant to all reports.

The ground is a product of continuing natural and man-made processes and therefore exhibits a variety ofcharacteristics and properties which vary from place to placeand can change with time. Geotechnical engineeringinvolves gathering and assimilating limited facts about thesecharacteristics and properties in order to understand orpredict the behaviour of the ground on a particular site undercertain conditions. This report may contain such factsobtained by inspection, excavation, probing, sampling,testing or other means of investigation. If so, they aredirectly relevant only to the ground at the place where andtime when the investigation was carried out.

DESCRIPTION AND CLASSIFICATION METHODS

The methods of description and classification of soils androcks used in this report are based on Australian Standard1726, the SAA Site Investigation Code. In general,descriptions cover the following properties – soil or rock type,colour, structure, strength or density, and inclusions.Identification and classification of soil and rock involvesjudgement and the Company infers accuracy only to theextent that is common in current geotechnical practice.

Soil types are described according to the predominatingparticle size and behaviour as set out in the attached UnifiedSoil Classification Table qualified by the grading of otherparticles present (e.g. sandy clay) as set out below:

Soil Classification Particle Size

Clay

Silt

Sand

Gravel

less than 0.002mm

0.002 to 0.075mm

0.075 to 2mm

2 to 60mm

Non-cohesive soils are classified on the basis of relativedensity, generally from the results of Standard PenetrationTest (SPT) as below:

Relative DensitySPT ‘N’ Value(blows/300mm)

Very loose

Loose

Medium dense

Dense

Very Dense

less than 4

4 – 10

10 – 30

30 – 50

greater than 50

Cohesive soils are classified on the basis of strength(consistency) either by use of hand penetrometer, laboratorytesting or engineering examination. The strength terms aredefined as follows.

ClassificationUnconfined CompressiveStrength kPa

Very Soft

Soft

Firm

Stiff

Very Stiff

Hard

Friable

less than 25

25 – 50

50 – 100

100 – 200

200 – 400

Greater than 400

Strength not attainable

– soil crumbles

Rock types are classified by their geological names,together with descriptive terms regarding weathering,strength, defects, etc. Where relevant, further informationregarding rock classification is given in the text of the report.In the Sydney Basin, ‘Shale’ is used to describe thinlybedded to laminated siltstone.

SAMPLING

Sampling is carried out during drilling or from otherexcavations to allow engineering examination (andlaboratory testing where required) of the soil or rock.

Disturbed samples taken during drilling provide informationon plasticity, grain size, colour, moisture content, minorconstituents and, depending upon the degree of disturbance,some information on strength and structure. Bulk samplesare similar but of greater volume required for some testprocedures.

Undisturbed samples are taken by pushing a thin-walledsample tube, usually 50mm diameter (known as a U50), intothe soil and withdrawing it with a sample of the soilcontained in a relatively undisturbed state. Such samplesyield information on structure and strength, and arenecessary for laboratory determination of shear strengthand compressibility. Undisturbed sampling is generallyeffective only in cohesive soils.

Details of the type and method of sampling used are givenon the attached logs.

INVESTIGATION METHODS

The following is a brief summary of investigation methodscurrently adopted by the Company and some comments ontheir use and application. All except test pits, hand augerdrilling and portable dynamic cone penetrometers requirethe use of a mechanical drilling rig which is commonlymounted on a truck chassis.

JK GeotechnicsGEOTECHNICAL & ENVIRONMENTAL ENGINEERS


Test Pits: These are normally excavated with a backhoe ora tracked excavator, allowing close examination of the insitusoils if it is safe to descend into the pit. The depth ofpenetration is limited to about 3m for a backhoe and up to6m for an excavator. Limitations of test pits are the problemsassociated with disturbance and difficulty of reinstatementand the consequent effects on close-by structures. Caremust be taken if construction is to be carried out near test pitlocations to either properly recompact the backfill duringconstruction or to design and construct the structure so asnot to be adversely affected by poorly compacted backfill atthe test pit location.

Hand Auger Drilling: A borehole of 50mm to 100mmdiameter is advanced by manually operated equipment.Premature refusal of the hand augers can occur on a varietyof materials such as hard clay, gravel or ironstone, and doesnot necessarily indicate rock level.

Continuous Spiral Flight Augers: The borehole isadvanced using 75mm to 115mm diameter continuousspiral flight augers, which are withdrawn at intervals to allowsampling and insitu testing. This is a relatively economicalmeans of drilling in clays and in sands above the water table.Samples are returned to the surface by the flights or may becollected after withdrawal of the auger flights, but they canbe very disturbed and layers may become mixed.Information from the auger sampling (as distinct fromspecific sampling by SPTs or undisturbed samples) is ofrelatively lower reliability due to mixing or softening ofsamples by groundwater, or uncertainties as to the originaldepth of the samples. Augering below the groundwatertable is of even lesser reliability than augering above thewater table.

Rock Augering: Use can be made of a Tungsten Carbide(TC) bit for auger drilling into rock to indicate rock qualityand continuity by variation in drilling resistance and fromexamination of recovered rock fragments. This method ofinvestigation is quick and relatively inexpensive but providesonly an indication of the likely rock strength and predictedvalues may be in error by a strength order. Where rockstrengths may have a significant impact on constructionfeasibility or costs, then further investigation by means ofcored boreholes may be warranted.

Wash Boring: The borehole is usually advanced by arotary bit, with water being pumped down the drill rods andreturned up the annulus, carrying the drill cuttings.Only major changes in stratification can be determined fromthe cuttings, together with some information from “feel” andrate of penetration.

Mud Stabilised Drilling: Either Wash Boring orContinuous Core Drilling can use drilling mud as acirculating fluid to stabilise the borehole. The term ‘mud’encompasses a range of products ranging from bentonite topolymers such as Revert or Biogel. The mud tends to maskthe cuttings and reliable identification is only possible fromintermittent intact sampling (eg from SPT and U50 samples)or from rock coring, etc.

Continuous Core Drilling: A continuous core sample isobtained using a diamond tipped core barrel. Provided fullcore recovery is achieved (which is not always possible invery low strength rocks and granular soils), this techniqueprovides a very reliable (but relatively expensive) method ofinvestigation. In rocks, an NMLC triple tube core barrel,which gives a core of about 50mm diameter, is usually usedwith water flush. The length of core recovered is comparedto the length drilled and any length not recovered is shownas CORE LOSS. The location of losses are determined onsite by the supervising engineer; where the location isuncertain, the loss is placed at the top end of the drill run.

Standard Penetration Tests: Standard Penetration Tests(SPT) are used mainly in non-cohesive soils, but can alsobe used in cohesive soils as a means of indicating density orstrength and also of obtaining a relatively undisturbedsample. The test procedure is described in AustralianStandard 1289, “Methods of Testing Soils for EngineeringPurposes” – Test F3.1.

The test is carried out in a borehole by driving a 50mmdiameter split sample tube with a tapered shoe, under theimpact of a 63kg hammer with a free fall of 760mm. It isnormal for the tube to be driven in three successive 150mmincrements and the ‘N’ value is taken as the number ofblows for the last 300mm. In dense sands, very hard claysor weak rock, the full 450mm penetration may not bepracticable and the test is discontinued.

The test results are reported in the following form:

In the case where full penetration is obtained withsuccessive blow counts for each 150mm of, say, 4, 6and 7 blows, as

N = 134, 6, 7

In a case where the test is discontinued short of fullpenetration, say after 15 blows for the first 150mm and30 blows for the next 40mm, as

N>3015, 30/40mm

The results of the test can be related empirically to theengineering properties of the soil.

Occasionally, the drop hammer is used to drive 50mmdiameter thin walled sample tubes (U50) in clays. In suchcircumstances, the test results are shown on the boreholelogs in brackets.

A modification to the SPT test is where the same drivingsystem is used with a solid 60 tipped steel cone of thesame diameter as the SPT hollow sampler. The solid conecan be continuously driven for some distance in soft clays orloose sands, or may be used where damage wouldotherwise occur to the SPT. The results of this Solid ConePenetration Test (SCPT) are shown as "N c” on the boreholelogs, together with the number of blows per 150mmpenetration.


Static Cone Penetrometer Testing and Interpretation:Cone penetrometer testing (sometimes referred to as aDutch Cone) described in this report has been carried outusing an Electronic Friction Cone Penetrometer (EFCP).The test is described in Australian Standard 1289, Test F5.1.

In the tests, a 35mm diameter rod with a conical tip ispushed continuously into the soil, the reaction beingprovided by a specially designed truck or rig which is fittedwith an hydraulic ram system. Measurements are made ofthe end bearing resistance on the cone and the frictionalresistance on a separate 134mm long sleeve, immediatelybehind the cone. Transducers in the tip of the assembly areelectrically connected by wires passing through the centre ofthe push rods to an amplifier and recorder unit mounted onthe control truck.

As penetration occurs (at a rate of approximately 20mm persecond) the information is output as incremental digitalrecords every 10mm. The results given in this report havebeen plotted from the digital data.

The information provided on the charts comprise:

Cone resistance – the actual end bearing force dividedby the cross sectional area of the cone – expressed inMPa.

Sleeve friction – the frictional force on the sleeve dividedby the surface area – expressed in kPa.

Friction ratio – the ratio of sleeve friction to coneresistance, expressed as a percentage.

The ratios of the sleeve resistance to cone resistancewill vary with the type of soil encountered, with higherrelative friction in clays than in sands. Friction ratios of1% to 2% are commonly encountered in sands andoccasionally very soft clays, rising to 4% to 10% in stiffclays and peats. Soil descriptions based on coneresistance and friction ratios are only inferred and mustnot be considered as exact.

Correlations between EFCP and SPT values can bedeveloped for both sands and clays but may be site specific.

Interpretation of EFCP values can be made to empiricallyderive modulus or compressibility values to allow calculationof foundation settlements.

Stratification can be inferred from the cone and frictiontraces and from experience and information from nearbyboreholes etc. Where shown, this information is presentedfor general guidance, but must be regarded as interpretive.The test method provides a continuous profile ofengineering properties but, where precise information on soilclassification is required, direct drilling and sampling may bepreferable.

Portable Dynamic Cone Penetrometers: PortableDynamic Cone Penetrometer (DCP) tests are carried out bydriving a rod into the ground with a sliding hammer andcounting the blows for successive 100mm increments ofpenetration.

Two relatively similar tests are used:

Cone penetrometer (commonly known as the ScalaPenetrometer) – a 16mm rod with a 20mm diametercone end is driven with a 9kg hammer dropping 510mm(AS1289, Test F3.2). The test was developed initiallyfor pavement subgrade investigations, and correlationsof the test results with California Bearing Ratio havebeen published by various Road Authorities.

Perth sand penetrometer – a 16mm diameter flat endedrod is driven with a 9kg hammer, dropping 600mm(AS1289, Test F3.3). This test was developed fortesting the density of sands (originating in Perth) and ismainly used in granular soils and filling.

LOGS

The borehole or test pit logs presented herein are anengineering and/or geological interpretation of the sub-surface conditions, and their reliability will depend to someextent on the frequency of sampling and the method ofdrilling or excavation. Ideally, continuous undisturbedsampling or core drilling will enable the most reliableassessment, but is not always practicable or possible tojustify on economic grounds. In any case, the boreholes ortest pits represent only a very small sample of the totalsubsurface conditions.

The attached explanatory notes define the terms andsymbols used in preparation of the logs.

Interpretation of the information shown on the logs, and itsapplication to design and construction, should therefore takeinto account the spacing of boreholes or test pits, themethod of drilling or excavation, the frequency of samplingand testing and the possibility of other than “straight line”variations between the boreholes or test pits. Subsurfaceconditions between boreholes or test pits may varysignificantly from conditions encountered at the borehole ortest pit locations.

GROUNDWATER

Where groundwater levels are measured in boreholes, thereare several potential problems:

Although groundwater may be present, in lowpermeability soils it may enter the hole slowly or perhapsnot at all during the time it is left open.

A localised perched water table may lead to anerroneous indication of the true water table.

Water table levels will vary from time to time withseasons or recent weather changes and may not be thesame at the time of construction.

The use of water or mud as a drilling fluid will mask anygroundwater inflow. Water has to be blown out of thehole and drilling mud must be washed out of the hole or‘reverted’ chemically if water observations are to bemade.


More reliable measurements can be made by installingstandpipes which are read after stabilising at intervalsranging from several days to perhaps weeks for lowpermeability soils. Piezometers, sealed in a particularstratum, may be advisable in low permeability soils or wherethere may be interference from perched water tables orsurface water.

FILL

The presence of fill materials can often be determined onlyby the inclusion of foreign objects (eg bricks, steel etc) or bydistinctly unusual colour, texture or fabric. Identification ofthe extent of fill materials will also depend on investigationmethods and frequency. Where natural soils similar tothose at the site are used for fill, it may be difficult withlimited testing and sampling to reliably determine the extentof the fill.

The presence of fill materials is usually regarded withcaution as the possible variation in density, strength andmaterial type is much greater than with natural soil deposits.Consequently, there is an increased risk of adverseengineering characteristics or behaviour. If the volume andquality of fill is of importance to a project, then frequent testpit excavations are preferable to boreholes.

LABORATORY TESTING

Laboratory testing is normally carried out in accordance withAustralian Standard 1289 ‘Methods of Testing Soil forEngineering Purposes’. Details of the test procedure usedare given on the individual report forms.

ENGINEERING REPORTS

Engineering reports are prepared by qualified personnel andare based on the information obtained and on currentengineering standards of interpretation and analysis. Wherethe report has been prepared for a specific design proposal(eg. a three storey building) the information andinterpretation may not be relevant if the design proposal ischanged (eg to a twenty storey building). If this happens,the company will be pleased to review the report and thesufficiency of the investigation work.

Every care is taken with the report as it relates tointerpretation of subsurface conditions, discussion ofgeotechnical aspects and recommendations or suggestionsfor design and construction. However, the Company cannotalways anticipate or assume responsibility for:

Unexpected variations in ground conditions – thepotential for this will be partially dependent on boreholespacing and sampling frequency as well as investigationtechnique.

Changes in policy or interpretation of policy by statutoryauthorities.

The actions of persons or contractors responding tocommercial pressures.

If these occur, the company will be pleased to assist withinvestigation or advice to resolve any problems occurring.

SITE ANOMALIES

In the event that conditions encountered on site duringconstruction appear to vary from those which were expectedfrom the information contained in the report, the companyrequests that it immediately be notified. Most problems aremuch more readily resolved when conditions are exposedthat at some later stage, well after the event.

REPRODUCTION OF INFORMATION FORCONTRACTUAL PURPOSES

Attention is drawn to the document ‘Guidelines for theProvision of Geotechnical Information in Tender Documents’ ,published by the Institution of Engineers, Australia. Whereinformation obtained from this investigation is provided fortendering purposes, it is recommended that all information,including the written report and discussion, be madeavailable. In circumstances where the discussion orcomments section is not relevant to the contractual situation,it may be appropriate to prepare a specially editeddocument. The company would be pleased to assist in thisregard and/or to make additional report copies available forcontract purposes at a nominal charge.

Copyright in all documents (such as drawings, borehole ortest pit logs, reports and specifications) provided by theCompany shall remain the property of Jeffery andKatauskas Pty Ltd. Subject to the payment of all fees due,the Client alone shall have a licence to use the documentsprovided for the sole purpose of completing the project towhich they relate. License to use the documents may berevoked without notice if the Client is in breach of anyobjection to make a payment to us.

REVIEW OF DESIGN

Where major civil or structural developments are proposedor where only a limited investigation has been completed orwhere the geotechnical conditions/ constraints are quitecomplex, it is prudent to have a joint design review whichinvolves a senior geotechnical engineer.

SITE INSPECTION

The company will always be pleased to provide engineeringinspection services for geotechnical aspects of work towhich this report is related.

Requirements could range from:

i) a site visit to confirm that conditions exposed are noworse than those interpreted, to

ii) a visit to assist the contractor or other site personnel inidentifying various soil/rock types such as appropriatefooting or pier founding depths, or

iii) full time engineering presence on site.

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CERTIFICATE OF ANALYSIS 139277

Client:

JK Geotechnics

PO Box 976

North Ryde BC

NSW 1670

Attention: Andrew Frost

Sample log in details:

Your Reference: 28879ZH, Homebush West

No. of samples: 3 Soils

Date samples received / completed instructions received 16/12/15 / 16/12/15

Analysis Details:

Please refer to the following pages for results, methodology summary and quality control data.

Samples were analysed as received from the client. Results relate specifically to the samples as received.

Results are reported on a dry weight basis for solids and on an as received basis for other matrices.

Please refer to the last page of this report for any comments relating to the results.

Report Details:

Date results requested by: / Issue Date: 23/12/15 / 21/12/15

Date of Preliminary Report: Not Issued

NATA accreditation number 2901. This document shall not be reproduced except in full.

Accredited for compliance with ISO/IEC 17025. Tests not covered by NATA are denoted with *.

Results Approved By:

Page 1 of 6Envirolab Reference: 139277

Revision No: R 00

Client Reference: 28879ZH, Homebush West

Misc Inorg - Soil

Our Reference: UNITS 139277-1 139277-2 139277-3

Your Reference ------------- BH1 BH7 BH9

Depth ------------ 0.7-0.95 0.7-0.9 0.5-0.95

Date Sampled

Type of sample

12/12/2015

Soil

12/12/2015

Soil

12/12/2015

Soil

Date prepared - 17/12/2015 17/12/2015 17/12/2015

Date analysed - 17/12/2015 17/12/2015 17/12/2015

pH 1:5 soil:water pH Units 5.6 6.9 5.6

Sulphate, SO4 1:5 soil:water mg/kg 200 340 56

Chloride, Cl 1:5 soil:water mg/kg 56 200 <10


Revision No: R 00


Method ID Methodology Summary

Inorg-001 pH - Measured using pH meter and electrode in accordance with APHA latest edition, 4500-H+. Please note

that the results for water analyses are indicative only, as analysis outside of the APHA storage times.

Inorg-081 Anions - a range of Anions are determined by Ion Chromatography, in accordance with APHA latest edition,

4110-B. Alternatively determined by colourimetry/turbidity using Discrete Analyer.


Revision No: R 00


QUALITY CONTROL UNITS PQL METHOD Blank Duplicate

Sm#

Duplicate results Spike Sm# Spike %

Recovery

Misc Inorg - Soil Base ll Duplicate ll %RPD

Date prepared - 17/12/2

015

[NT] [NT] LCS-1 17/12/2015

Date analysed - 17/12/2

015

[NT] [NT] LCS-1 17/12/2015

pH 1:5 soil:water pH Units Inorg-001 [NT] [NT] [NT] LCS-1 101%

Sulphate, SO4 1:5

soil:water

mg/kg 10 Inorg-081 <10 [NT] [NT] LCS-1 97%

Chloride, Cl 1:5

soil:water

mg/kg 10 Inorg-081 <10 [NT] [NT] LCS-1 106%


Revision No: R 00


Report Comments:

Asbestos ID was analysed by Approved Identifier: Not applicable for this job

Asbestos ID was authorised by Approved Signatory: Not applicable for this job

INS: Insufficient sample for this test PQL: Practical Quantitation Limit NT: Not tested

NR: Test not required RPD: Relative Percent Difference NA: Test not required

<: Less than >: Greater than LCS: Laboratory Control Sample


Revision No: R 00


Quality Control Definitions

Blank: This is the component of the analytical signal which is not derived from the sample but from reagents,

glassware etc, can be determined by processing solvents and reagents in exactly the same manner as for samples.

Duplicate : This is the complete duplicate analysis of a sample from the process batch. If possible, the sample

selected should be one where the analyte concentration is easily measurable.

Matrix Spike : A portion of the sample is spiked with a known concentration of target analyte. The purpose of the matrix

spike is to monitor the performance of the analytical method used and to determine whether matrix interferences exist.

LCS (Laboratory Control Sample) : This comprises either a standard reference material or a control matrix (such as a blank

sand or water) fortified with analytes representative of the analyte class. It is simply a check sample.

Surrogate Spike: Surrogates are known additions to each sample, blank, matrix spike and LCS in a batch, of compounds

which are similar to the analyte of interest, however are not expected to be found in real samples.

Laboratory Acceptance Criteria

Duplicate sample and matrix spike recoveries may not be reported on smaller jobs, however, were analysed at a frequency

to meet or exceed NEPM requirements. All samples are tested in batches of 20. The duplicate sample RPD and matrix

spike recoveries for the batch were within the laboratory acceptance criteria.

Filters, swabs, wipes, tubes and badges will not have duplicate data as the whole sample is generally extracted

during sample extraction.

Spikes for Physical and Aggregate Tests are not applicable.

For VOCs in water samples, three vials are required for duplicate or spike analysis.

Duplicates: <5xPQL - any RPD is acceptable; >5xPQL - 0-50% RPD is acceptable.

Matrix Spikes, LCS and Surrogate recoveries: Generally 70-130% for inorganics/metals; 60-140%

for organics (+/-50% surrogates) and 10-140% for labile SVOCs (including labile surrogates), ultra trace organics

and speciated phenols is acceptable.

In circumstances where no duplicate and/or sample spike has been reported at 1 in 10 and/or 1 in 20 samples

respectively, the sample volume submitted was insufficient in order to satisfy laboratory QA/QC protocols.

When samples are received where certain analytes are outside of recommended technical holding times (THTs),

the analysis has proceeded. Where analytes are on the verge of breaching THTs, every effort will be made to analyse

within the THT or as soon as practicable.

Where sampling dates are not provided, Envirolab are not in a position to comment on the validity

of the analysis where recommended technical holding times may have been breached.


Revision No: R 00