Final NHBRC Phase I Geotechnical Report for the Proposed

1

Final NHBRC Phase I Geotechnical Report for the

Proposed Township Development, Portion 419 of

Farm 61 in uPhongola, KwaZulu-Natal

Client: MNT Geomatics

Reference: 16-0816R01

Dated: 6 October 2016

GCS Geotechnical 63 Wessels Street

Rivonia

Cell: +27 (0)82 567 1561

[email protected]

www.gcs-sa.biz

Site Investigations Borrow Pits and Materials

Slope Stability Roads

Rock Mechanics Groundwater

Soil Mechanics

Foundations

NHBRC

Geotechnical Instrumentation

2




Reference: 16-0816R01 Date: 6 October 2016

TABLE OF CONTENTS

1. INTRODUCTION & TERMS OF REFERENCE .............................................................. 5 2. AVAILABLE INFORMATION ........................................................................................... 5 3. SITE DESCRIPTION ............................................................................................................ 6 4. GEOLOGY ............................................................................................................................. 7 5. FIELDWORK ........................................................................................................................ 7 6. GROUNDWATER ................................................................................................................. 8 7. LABORATORY TESTING .................................................................................................. 8 8. FINAL DEVELOPMENT RECOMMENDATIONS ......................................................... 9 8.1 Trenchability and Rippability Assessment ............................................................................................. 9 8.2 Drainage .................................................................................................................................................. 9 8.3 Earthworks and Site Clearance ............................................................................................................. 10 8.4 Settlement/Heave Analysis ................................................................................................................... 11 8.5 NHBRC Site Classifications ................................................................................................................. 11 8.6 Foundation Recommendation ............................................................................................................... 11 8.7 Surface Beds ......................................................................................................................................... 12 8.8 Recommended Subgrade Treatment ..................................................................................................... 12 8.9 Pipe Bedding ......................................................................................................................................... 12 9. CONCLUSIONS & RECOMMENDATIONS .................................................................. 13

Appendix A TLB-excavated Inspection Pit Profiles

Appendix B Laboratory Test Results

Figure 1 Site Plan

Figure 2 Geological Plan

3

EXECUTIVE SUMMARY

This final NHBRC Phase I geotechnical report contains the findings and development

recommendations for the construction of the proposed township to be located on Portion

419 of Farm 61 in uPhongola.

It is considered that the conditions prevailing on site are such that the majority of the site is

considered suitable for the proposed development, provided the recommendations outlined

in this final report are adhered to. The main geotechnical constraints to the development

will be collapsible subsoils.

Six disturbed and four undisturbed samples were taken from the inspection pit excavations

for laboratory analysis. Particle size distribution (PSD), hydrometer analysis and Atterberg

limits determination are currently being carried, and the four undisturbed samples were sent

for collapse potential testing. The laboratory test results are included in Appendix B.

The site is underlain by quaternary alluvial age sediments and the bedrock is andalusite-

sericite schist and amphibole schist of the Mphushana Formation, Mozaan Group. Soft

excavation in terms of SABS 1200 D is generally anticipated to depths in excess of 2.9 m

below natural ground level over the site.

One of the more important factors in the promotion of a stable site is the control and removal

of surface water from the property. It is important that the design of the storm water

management system, allow for the drainage of accumulated surface water from the platform

and into the storm water system or natural drainage lines.

The NHBRC Site Classification is C1-C2 for majority of the site. The options for suitable

foundations are:

Modified normal with articulation joints at some internal and all external doors, or

Compaction of in-situ soils below individual footings, or

Soil or RC raft

Stiffened strip footings

Finally, it must be understood that the ground conditions described in this report refer

specifically to those encountered at the test positions on site. It is therefore possible that

conditions at variance with those discussed above may be encountered elsewhere on the

property.

In this regard it is important that GCS Geotechnical carry out periodic inspections of the

site during construction to ensure that any variation in the anticipated ground conditions

can be assessed, and revised recommendations made to avoid unnecessary delays and

expense.

Furthermore it is emphasised that this report satisfies the requirements of an NHBRC Phase

I shallow geotechnical investigation for township proclamation and town planning

purposes. The final estimation of the appropriate foundation options for each erf/stand

should be determined by a NHBRC Phase 2 investigation during service trench construction.

4

Definitions and Abbreviations

Commercial:

GCS Geotechnical GCS Geotechnical (Pty.) Ltd.

Technical:

CH Chainage (metres)

mbgl metres below ground level

masl metres above sea level

NGL Natural Ground Level

FL Foundation Level

BH Borehole

SPT Standard Penetration Test

N SPT N value (blows per 300 mm)

TLB Tractor-mounted Loader Backhoe

TP Test Pit

DCP Dynamic Cone Penetrometer

EABC Estimated Allowable Bearing Capacity

G1-G10 Standard classification of natural road building materials (TRH 14)

CBR California Bearing Ratio

MDD Maximum Dry Density (kg/m3)

MADD Modified AASHTO Dry Density

OMC Optimum moisture Content (%)

PI Plasticity Index

LL Liquid Limit

LS Linear Shrinkage

RMR Rock Mass Rating

GSI Geological Strength Index

mi Hoek-Brown Constant (origin & texture dependent)

RQD Rock Quality Designation (%)

FF Fracture frequency

UCS Unconfined Compressive Strength (MPa)

C (c’) Cohesion (kPa) – total stress and (effective stress)

Φ (Φ’) Friction Angle (degrees) – total stress and (effective stress)

Kv Modulus of Subgrade Reaction (MN/mm or kPa/mm)

CFA Continuous Flight Auger (pile type)

DCI Driven Cast In situ (pile type)

Cv Coefficient of Consolidation (m2/yr)

Mv Modulus of Compressibility (m2/MN)

MC1 Moisture Content Before Test (%)

MC2 Moisture Content After Test (%)

ρ Dry Density (kg/m3)

VSR Very soft rock

SR Soft rock

MHR Medium hard rock

HR Hard rock

VHR Very hard rock

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Reference: 16-0816R01 Date: 6 October 2016

1. INTRODUCTION & TERMS OF REFERENCE

At the request of Mr. Muzi Mntambo of MNT Geomatics, GCS Geotechnical (hereafter

referred to as GCS) was asked to provide a proposal and cost estimate quotation, in an email

dated 4th July 2016, for the undertaking of a NHBRC Phase I geotechnical investigation for

the proposed township development on Portion 419 of Farm 61 in uPhongola, KwaZulu-

Natal.

2. AVAILABLE INFORMATION

The following information was drawn upon for the purposes of the investigation:

The 1:250 000 Geological Map titled “2730 Vryheid” as compiled by the South

African Geological Survey, 1986.

Google Earth historical imagery

Brink (1985) Vol. 4

SABS 1200 D – Earthworks

Two drawings showing proposed unit developments

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Table 2-1: Summary of Available Desk Study Information

Parameter Value Reference

Development Residential MNT Geomatics

Site co-ordinates 27.35954° S / 31.58262° E

MNT Geomatics

Weinert’s N-value 2-5 Weinert (1974)

Climatic Region Moderate TRH 2 (1978)

Rainfall >1500 mm King, 2003

Temperature 20-22.5˚ C after DWAF (1986)

Evaporation 1400-1600 mm After DWAF (1986)

Water Balance Normal Schulze (1985)

Weathering Type Moderate decomposition Fookes et al (1971)

Geology Alluvium, andalusite-sericite

schist and amphibolite schist.

2730 Vryheid 1:250 000 scale

Soil Cover Colluvium, talus and alluvium Brink (1985)

Origin Discontinuous cover of fine

colluvial soils

Brink (1985)

Drainage To east Garmap SA Topo & Rec 2012.1

Drainage Region Quaternary Catchment: W44 DWAF (1999)

Hydrogeology Intergranular & fractured (0.5-2

l/s)

King, 2003

Groundwater depth 20 m King, 2003

Erodibility Index 1-15 (Moderate to high) WRC (1992)

Seismic Intensity VI (MMS) Fernandez et al (1972)

Liquefaction Marginal (50-100 cm/s²) Welland (2002)

3. SITE DESCRIPTION

The proposed township development is located approximately 5 km north-west from the

center of uPhongola, in KwaZulu-Natal. The central co-ordinates of the site are 27.35954°

S / 31.58262° E.

The total site area comprises 19 ha and majority of the site is undeveloped with the exception

of 2 kraals. The site is bound to the north-west by an existing township and to the east, west

and south by sugar cane plantations.

Topographically, the site falls in a north easterly direction from 369 to 339 masl at a gradient

of 1:13. The site is poorly vegetated and serves as a grazing field for cattle, and hosts a

network of rudimentary pathways criss-crossing the site.

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4. GEOLOGY

Regionally, the site is underlain by quaternary alluvial age sediments, which in turn is

underlain by andalusite-sericite schist and amphibole schist of the Mphushana Formation,

Mozaan Group. A prominent fault passes the site to the east in a north-south direction.

5. FIELDWORK

Twenty TLB-excavated inspection pits (hereafter referred to as IP’s) were opened across the

site, in order to ascertain the general geotechnical engineering properties of the subsurface

materials.

5.1 TLB-Excavated Inspection Pits

In general the soil profile showed an open-grained structure (generally indicative of collapse)

as well as instances of bioturbation, reworking and mulching. A summary of the inspection

pits can be found below in Table 5.1 below. The detailed inspection pit profiles are provided

in Appendix A. The results of the IP’s suggested refusal depths ranging between 1.2 m and

2.9 m below existing ground level, refusing on cobbles and boulders, or by simply reaching

the maximum depth of excavation with a TLB, without intercepting bedrock.

The depth to bedrock could not be confirmed in this shallow investigation, and the possibility

of encountering bedrock or boulders below the final depths of the test pits cannot be ruled

out.

Table 5.1: Summary of Test Pit Profiles

Depth

(m-m)

Description EABC

(kPa)

Kv

(kPa/mm)

E (MPa) or

C (kPa)

Notes

Colluvium

0.0-1.4 Dry to slightly moist, dark reddish

brown to dark orange brown,

FIRM TO STIFF, pin-holed and

bioturbated, slightly sandy silty

Clay.

25-200 35-65 36-144

-Pin-holed

-Ferruginized nodules

-Rootlets.

1.4-2.8 Slightly moist, dark reddish brown

to orange brown, SOFT TO FIRM,

pin-holed, slightly sandy silty Clay.

25-100 35-65 18-72

-Pin-holed

-Ferruginized nodules

-Rootlets.

Talus

0.0-1.6 Dry to slightly moist, dark brown to

dark orange brown, SOFT TO

FIRM, pinholed and bioturbated,

slightly sandy silty Clay.

25-100 35-65 18-72 -Pin-holed

1.6-2.5 Slightly moist, dark reddish brown

to dark orange brown, LOOSE TO

MEDIUM DENSE, pin-holed,

clayey silty Sand.

75-250 55-100 3-12

-Pinholed

-Abundant medium to

course rock fragments

and boulders

All the samples rated as low potential expansiveness.

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6. GROUNDWATER

No groundwater seepage occurred in any of the inspection pit’s excavated on site although

during the rainy season perched water levels should be expected at the weathered bedrock

interface. The regional groundwater level resides at about 20 m below surface.

7. LABORATORY TESTING

Laboratory tests have been scheduled on six disturbed soil samples and four undisturbed soil

samples recovered from the site.

The following tests are being carried out:

Foundation indicator tests (PSD, hydrometer and Atterberg Limits), and

Collapse potential tests.

The laboratory test results and analysis will determine the material quality for earthworks

and layer-works suitability, as well as foundation characteristics. The laboratory test results

are included in Appendix B with a summary in Table 7-1 below:

Table 7-1: Summary of Foundation Indicators

TP Depth

(m-m) LL PI GM

LS CBR*

(%)

Classifications

TRH14 PRA USCS

Hillwash

1 0.0-2.1 41 15 0.12 7.0 7-8 G10 A-7-6(10) CL

17 1.0-2.6 38 18 0.15 9.0 6-7 G10 A-6(11) CL

Talus

1 2.1-2.8 33 10 0.38 5.0 12-13 G10 A-4(8) SC

2 2.5-2.85 41 12 0.54 6.0 12-13 G10 A-7-6(0) ML-

O

L

5 1.8-2.3 40 16 1.53 8.0 19-20 G10 A-6(4) SC

6 2.6-2.7 34 11 2.40 5.5 45-50 G7 A-2-6(0) GC

*CBR estimated at 93-95% MADD from PI-GM relationship.

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Table 7-2: Collapse Potential Results

TP Depth

(m-m)

MCa*

(%)

MCb**

(%)

Dry

density

(kg/m3)

e0 CP200***

(%)

Settlement

(mm)

Hillwash/colluvium

1 1.3-1.4 15.43 26.99 1500 0.720 1.6 24

5 0.6-0.7 11.27 23.90 1586 0.683 0.4 6

9 1.0-1.2 21.01 31.25 1275 1.110 7.0 84

Talus

13 1.7-1.8 26.84 40.0 1246 1.152 7.0 6 *MCa = moisture content before soaking

**MCb = moisture content after soaking

***CP200 = collapse potential at 200 kPa

8. FINAL DEVELOPMENT RECOMMENDATIONS

8.1 Trenchability and Rippability Assessment

From information gleaned from the field investigation, the excavatibility of the site in terms

of SABS 1200D can be classified as “soft excavation” from surface to depths in excess of

2.9 m below natural ground level.

8.2 Drainage

The most important factor in the promotion of a stable site is adequate drainage, both surface

and subsurface, be constructed so that no water ingress into the subsurface soils in and

around the foundation base is possible. The natural ingress of groundwater and the additional

localised inundation due to the development itself should be managed and controlled to

prevent erosion and the collapse settlement of materials.

Drainage should be such that any rainfall is diverted to the nearest stormwater drainage

system. Areas of potential pooling or damming of rainfall on site should be carefully

designed and sloped so as to remove this water from the site. Once excavations have been

opened, they are to be blinded with mass concrete as soon as possible, so as to prevent any

rainfall occurring having an impact on the founding soils.

All drainage installations should be completed prior to building construction.

8.2.1 Surface Drainage

Surface drainage of building platforms should be designed to direct water away from fill

edges, to prevent overtopping of the fill crest and erosion of fill embankment slopes. Surface

water on these platforms should be directed to, and collected in, open lined drains or piped

to the natural drainage line.

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It is important that grassing or protection of fill embankments be carried out as soon as

possible after construction, to minimise ponding of the water on the cut platforms to reduce

slope instability and piping erosion.

Run-off from building roofs should be piped from gutters, through downpipes, and

discharged into the storm water reticulation system. In addition a suitable concrete apron

should be provided at least 1.5 m wide and shaped away from the edge of the structure to

ensure effective run-off.

Since the area to be developed is in excess of 0.8 hectares, the storm water received onto and

generated on the site will have to be managed and attenuated on site.

8.2.2 Sub-Surface Drainage

It is strongly recommended that the subsoil drains (if required) be designed according to the

specific filter criteria of the in situ soils to prevent piping of the material and subsequent

rapid erosion.

8.3 Earthworks and Site Clearance

8.3.1 Site Clearance

All vegetation should be cleared from the areas over which structures are to be built. Any

removal of surface topsoil will probably bring any groundwater seepage closer to the surface

and this should be borne in mind and made clear to the contractor.

Earthworks should commence shortly after vegetation clearing to prevent erosion runoff

along the steeply sloping western slope.

8.3.2 Earthworks

It is recommended that all earthworks be carried out in accordance with SABS 1200 D.

In general, it is recommended that cut slopes and fill embankments have a maximum

slope of 1 vertical to 2 horizontal to ensure stability. Excavation with unsupported side

walls will remain relatively stable for short periods (less than 24 hours) unless they are

destabilized by a storm or a perched groundwater seepage. The need for the subsoil drainage

both beneath and in fills will have to be assessed during the earthworks, taking into account

the height and locality of individual fills.

The fills should be placed in layers not exceeding 200mm loose thickness, and compacted

to a minimum of 93% Modified AASHTO maximum dry density at 2% wet of optimum

moisture content. Cobbles and boulders larger than ²/3 of the layer thickness and clayey

or organic material must not be included in the fill material.

Both during and after construction, the site should be well graded to permit water to drain

away readily and to prevent ponding anywhere on the ground surface. All terraces and

earthworks in general should be sloped to a gradient of not less than 1 vertical in 50

horizontal to prevent ingress of water into the subsoils since these soils might be

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significantly permeable. Surface drainage should be directed away from the crests of fill

embankments to prevent over-topping and erosion of fill slopes.

Backfill to service trenches must be raised slightly above the surrounding ground level and

be properly compacted to avoid the formation of a surface depression as a result of settlement

of the backfill. Such depressions will increase the ingress of stormwater runoff into the soils.

It is recommended that the number of trenches running at right angles to contours be limited

as these often become preferential drainage paths. All service trenches deeper than 1.5m

must be shored.

8.4 Settlement/Heave Analysis

Based on the laboratory test results, visual and tactile descriptions, the shallow foundation

soils (colluvium & talus) have been described as pin-holed and therefore prone to collapse

settlements ranging from 6 mm to 84 mm at an average of 30 mm (due to a collapse potential

ranging from 0.4 to 7%).

The laboratory test results show that the clayey subsoils are inert and not prone to heave.

8.5 NHBRC Site Classifications

Based on the conclusions provided in section 8.4 above, the NHBRC Site Classification for

majority of the site is C2 with minor zones of C1.

8.6 Foundation Recommendation

Under no circumstances should foundations be placed in/on untreated natural subsoils unless

it has been specifically engineered to support structural foundations.

In general, good practice requires that the in situ moisture content of the founding horizons

below the structure be maintained, and in this regard the following precautions should be

taken:

No water should be allowed to pond against or within the first meter from the external

perimeter of the structure.

Gardens located against the external perimeter of the structure are not recommended.

Leaks in plumbing and associated drainage are attended to without delay.

No large shrubs and or trees are planted closer than 0.75 x the mature height of the

tree.

Septic tanks and French drains are situated well away down gradient from any

buildings.

It is not, however, cost effective to construct foundations which totally remove the chance

of damage due to soil movements and in this light, some Category 1 damage to the structures

may be expected, i.e., fine internal cracks of widths less than 1 mm aperture. To a much

lesser extent some Category 2 damage may occasionally occur, with the formation of cracks

of less than 5 mm aperture. It is recommended that GCS Geotechnical inspect and approve

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all foundation excavations to confirm depth of founding and bearing capacity of the

underlying founding horizons.

Given the results of the inspection pits, and the relatively low in situ moisture content (dry

to slightly moist), it is clear that the upper 2.4m of the soil profile will have a high collapse

potential. A high likelihood thus exists for collapse potential should there be a sudden ingress

of water resulting in saturation of the foundation soils. This may occur should services

adjacent to walls and foundations rupture or crack, or if water is allowed to pond against the

walls of the structure. The following foundation options should be considered:

NHBRC Site Class C1:

Modified normal with articulation joints and reinforced strip footings, or

Compaction of in-situ soils below individual footings with lightly reinforced strip

foundations and light reinforcement in masonry, or

Soil raft by removing in situ material to 1 m beyond perimeter of building to a depth

of 1.5 times widest footing and replace with inert approved (G7) material compacted

to 93% MADD. Normal construction with lightly reinforced strip footings and light

reinforcement in masonry.

NHBRC Site Class C2:

Stiffened strip footings with articulation joints or solid lightly reinforced masonry.

Bearing pressure not to exceed 50 kPa and fabric reinforcement in floor slab.

RC raft with same details as above.

Compaction of in situ soils below individual footings with lightly reinforced strip

foundations and light reinforcement in masonry.

Soil raft as above

8.7 Surface Beds

The upper soils would likely be considered adequate as subgrade materials after compaction.

The design value for the modulus of subgrade reaction (k) for floor slab design would

normally be between 35 and 65 kPa/mm provided the subgrade beneath surface beds or floor

slabs can be ripped to a depth of 300mm and re-compacted to 93% Mod AASHTO dry

density.

8.8 Recommended Subgrade Treatment

Transported materials tend to be highly variable in thickness and composition, and would

likely appear as sandy silty clay. However, these materials can be potentially collapsible and

therefore it is suggested that the upper 300mm be ripped, wetted to +2% of OMC and

compacted to 93% MADD.

8.9 Pipe Bedding

It is unlikely that the situ materials occurring on site would meet the strict bedding

specifications, according to the requirements of SABS 1200LB and therefore this

commodity should be allowed for in the tender documents.

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9. CONCLUSIONS & RECOMMENDATIONS

This final NHBRC Phase I geotechnical report contains the findings and development

recommendations for the construction of the proposed township development on portion

419 of Farm 61 Phongola, KwaZulu-Natal.

It is considered that the conditions prevailing on site during the site investigation are

such that the majority of the site is considered suitable for the proposed development,

provided that the recommendations outlined in this report are adhered to. The main

geotechnical constraints to the development will be collapsible subsoils.

Six disturbed and four undisturbed samples were taken from the inspection pit

excavations for laboratory analysis. The six disturbed samples were sent for particle size

distribution, hydrometer analysis and Atterberg limits determination, and the four

undisturbed samples were sent for consolidometer testing. A summary of the results are

provided.

The site is underlain by transported fine colluvial material, which is underlain by coarse-

grained talus and andalusite-sericite schist and amphibole schist.

Soft excavation in terms of SABS 1200D is generally anticipated from surface to depths

in excess of 2.9 m below natural ground level.

Final recommendations for earthworks and drainage to promote stable development are

given.

Due to the collapse potential of the underlying colluvium, the NHBRC Site Classification

ranges from C1 to C2.

Due to the predominantly dry to slightly moist moisture condition, pin-holed structure

and loose to medium dense consistency of the clayey sands and firm to stiff consistencies

of the silty clays to depths in excess of 2.9 m, it is advised that the most appropriate

foundations options are modified normal strip footings, RC rafts or a compacted soil raft.

One of the more important factors in the promotion of a stable site is the control and

removal of surface water from the property. It is important that the design of the storm

water management system, allow for the drainage of accumulated surface water from the

platform and into the municipal storm water system or natural drainage lines.

Finally, it must be understood that the ground conditions described in this report refer

specifically to those encountered at the inspection positions on site. It is therefore

possible that conditions at variance with those discussed above may be encountered

elsewhere on the property.

In this regard it is important that GCS Geotechnical carry out periodic inspections of the

site during construction to ensure that any variation in the anticipated ground conditions

can be assessed, and revised recommendations made to avoid unnecessary delays and

expense. This constitutes the require NHBRC Phase II investigation which will entail the

14

mapping of individual service trench excavations to provide a more accurate NHBRC

Site Classification for each erf/stand after these have been pegged.

____________________ 6 October 2016

For GCS Geotechnical

[email protected]

www.gcs-sa.biz

mailto:[email protected]

http://www.gcs-sa.biz/

Appendix A

TLB-Excavated Inspection Pit Profiles

Appendix B

Laboratory Test Results

Project: Farm 61 - 21887Client.: Soilco Hole/Block: TP 1Date: 30-09-2016 Depth (m): 1.3 - 1.4Sample No.: 09025 Consol No.: 5Sample Description: - Ring Dial. (mm): 76.75

Gauge Divs.(mm): 0.002 Specific Gravity: 2.58

Container No.: 23 Moisture content before testing (%): 15.43Mass of container (g): 81.81 Moisture content after testing (%): 26.99Mass of wet sample + container before testing (g): 234.02 Dry density before testing (kg/m3): 1500Mass of wet sample + container after testing (g): 249.26 Bulk density before testing (kg/m3): 1732Mass of dry sample + container (g): 213.67 Percentage saturation before test (%): 55.30

Percentage saturation after test (%): 108.10

Applied Dial Void Modulus of Compressibility MvPressure Reading Ratio Stress Mv Stress Mv(KPa) (divs) Range(kPa) (kPa-1) Range(kPa) (kPa-1)

1 5000 0.72025 4903 0.704 1 - 25 3.95E-04 1 - 25 3.95E-0450 4849 0.695 25 - 50 2.09E-04 1 - 50 2.99E-04

100 4789 0.685 50 - 100 1.11E-04 1 - 100 2.03E-04200 4699 0.672 100 - 200 8.27E-05 1 - 200 1.42E-04200 4548 0.644 200 - 200 #DIV/0! 1 - 200 2.22E-04NA NA NA NA NA NANA NA NA NA NA NA NANA NA NA NA NA NA NANA NA NA NA NA NA NANA NA NA NA NA NA NANA NA NA NA NA NA NA

Graph DataPrint PlotX Y

1 0.720062825 0.7037734450 0.69488727

100 0.68547286200 0.67153496200 0.64419737200 0.64419737200 0.64419737200 0.64419737200 0.64419737200 0.64419737200 0.64419737

Reference no.: 8228 Drennan Maud and Partners

Fig. no. -

Collapse Potential (%)

1.62

0.6

0.62

0.64

0.66

0.68

0.7

0.72

0.74

1 10 100 1000

Vo

id R

atio

(e)

Pressure (kPa)

Void Ratio (e) vs Log Pressure

Collapse Potential






1 5000 0.68325 4919 0.670 1 - 25 3.24E-04 1 - 25 3.24E-0450 4876 0.663 25 - 50 1.62E-04 1 - 50 2.41E-04



1 0.6831823125 0.6700768150 0.66332995

100 0.65766063200 0.64915927200 0.64295861200 0.64295861200 0.64295861200 0.64295861200 0.64295861200 0.64295861200 0.64295861


Fig. no. -


0.36

0.6

0.61

0.62

0.63

0.64

0.65

0.66

0.67

0.68

0.69

0.7

1 10 100 1000

Vo

id R

atio

(e)

Pressure (kPa)


Collapse Potential






1 5000 1.11025 4919 1.094 1 - 25 3.24E-04 1 - 25 3.24E-0450 4854 1.080 25 - 50 2.55E-04 1 - 50 2.88E-04



1 1.1101763125 1.0937461750 1.08040144

100 1.06885182200 1.04642227200 0.89827845200 0.89827845200 0.89827845200 0.89827845200 0.89827845200 0.89827845200 0.89827845


Fig. no. -


7.01

0.8

0.85

0.9

0.95

1

1.05

1.1

1.15

1.2

1 10 100 1000

Vo

id R

atio

(e)

Pressure (kPa)


Collapse Potential






1 5000 1.15225 4917 1.135 1 - 25 3.33E-04 1 - 25 3.33E-0450 4854 1.122 25 - 50 2.47E-04 1 - 50 2.88E-04



1 1.151894125 1.1346861550 1.12153059

100 1.10975264200 1.08687966200 0.93580706200 0.93580706200 0.93580706200 0.93580706200 0.93580706200 0.93580706200 0.93580706


Fig. no. -


7.02

0.9

0.95

1

1.05

1.1

1.15

1.2

1 10 100 1000

Vo

id R

atio

(e)

Pressure (kPa)


Collapse Potential

Figure 1

Site Plan

Figure 2

Geological Plan

Documents

Final NHBRC Phase I Geotechnical Report for the Proposed