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KING OFFA NURSERY

BEXHILL

EAST SUSSEX

GEOTECHNICAL REPORT

ON THE GROUND INVESTIGATION

Report No. LW23258 November 2012

Report prepared for the benefit of:

ESCC Children’s Services

c/o Mackellar Schwerdt Architects

The Old Library

Albion Street

Lewes

BN7 2ND

GEOTECHNICALANDENVIRONMENTALENGINEERS

Head Offi ceThe Old Dairy

Swanborough Farm

Swanborough

Lewes

East Sussex

BN7 3PF

Telephone

0870 777 1574

Fascimile

0870 777 1577

Website

www.AshdownSI.co.uk

Email

[email protected]

Regional Offi ce

Hertfordshire

(Contact via Head Offi ce)

Managing Director

J.E.Bewick

BSc MSc CEnv CEng MICE

Company Secretary

V.Bewick

BSc MSc FRSS

Company Registration Number

242 6786

KING OFFA NURSERY

BEXHILL

EAST SUSSEX

GEOTECHNICAL REPORT


REPORT NO. LW23258 NOVEMBER 2012

FACTUAL REPORT

Prepared By:

Tim Howard BEng FGS

Approved By:

John Bewick BSc MSc CEng CEnv MICE

GEOTECHNICAL ASSESSMENT

Prepared By:

Tim Howard BEng FGS

Approved By:

John Bewick BSc MSc CEng CEnv MICE

Report No: LW23258/contents

KING OFFA NURSERY

BEXHILL

EAST SUSSEX

GEOTECHNICAL REPORT


TABLE OF CONTENTS

Page i of i

Page

1. INTRODUCTION 1

2. GROUND INVESTIGATION 2

2.1 Expected Geology 2

2.2 Ground Investigation 2

2.3 Laboratory Testing 2

2.4 Ground Conditions 3

3. GEOTECHNICAL ASSESSMENT 4

3.2 Groundwater 5

3.3 Stability of Excavations 5

3.4 Aggressivity to Concrete 6

3.5 Ground Floors 6

3.6 Pavement Design 6

3.7 Drainage 7

4. CONCLUSIONS 8

APPENDIX A

Exploratory Hole Notes Exploratory Hole Records DPSH Profiles TRL Profiles Summary of Borehole Falling Head Soakage Test Results Summary of Trial Pit Falling Head Soakage Test Results

APPENDIX B

Geotechnical Laboratory Testing Notes Laboratory Test Results

FIGURES

Figure 1 Site Plan Figure 2 Exploratory Hole plan

Report No: LW23258

King Offa Nursery Page 1 of 9 Bexhill, East Sussex

1. INTRODUCTION

It is proposed to construct a new Nursery to the north of the existing King Offa Primary School, Down Road, Bexhill. Ashdown Site Investigation Limited was commissioned to carry out an intrusive ground investigation at the site by Mr Stephen Kemp of Mackellar Schwerdt Architects on behalf of the client ESCC. The instruction to proceed was received in an email, dated 5

th October 2012.

The purpose of the works was to:

i. assess ground and shallow groundwater conditions prevailing at the site; and

ii. provide information to assist others in undertaking design of spread foundations, ground floors, road pavements and soakaways.

The analysis and discussions contained in this report are based on the ground conditions encountered during the recent site work. The possibility of a variation in ground and groundwater conditions away from the positions investigated should not be overlooked. Groundwater conditions can vary both seasonally and due to other effects. It is noted that the investigation was undertaken and the report has been report prepared specifically for the Client’s project and the recommendations given may not be appropriate to alternative applications. The copyright for the report and licence for its use shall remain vested in Ashdown Site Investigation Limited (the Company) who disclaim all responsibility or liability (whether at common law or under the express or implied terms of the Contract between the Company and the Client) for any loss or damage of whatever nature in the event that this report is relied on by a third party, or is issued in circumstances or for projects for which it was not originally commissioned, or where the exploratory hole records and test results contained therein are interpreted by anyone other than the Company.

Report No: LW23258


2. GROUND INVESTIGATION

2.1 Expected Geology

The stratigraphic unit that may be anticipated to underlie the site is the Tunbridge Wells Sand Formation. These deposits generally comprise rhythmically bedded sandstones, siltstones and mudstone. The Tunbridge Wells Sand Formation is commonly differentially weathered to form dense sand or silt and stiff clay. The mudstones commonly weather to red clay and the siltstones and sandstones to mottled grey and orange silts and sands.

2.2 Ground Investigation

The ground investigation comprised the excavation of four dynamic sampler boreholes with continuous DPSH penetration testing carried out from ground level adjacent to each of the boreholes. Transport Road Laboratory (TRL) cone penetration tests for CBR determination were carried out at selected positions. In addition, falling head soakage tests were carried within boreholes BH2 and BH3, and within shallow trial pits excavated adjacent to these boreholes. Descriptions of the strata encountered and comments on groundwater conditions are shown in the exploratory hole records given in Appendix A.

2.3 Laboratory Testing

Geotechnical testing was undertaken by Ashdown Site Investigation Ltd in accordance with the methods given in BS1377:1990 Parts 1 to 8 ‘Methods of test for soils for civil engineering purposes’. Notes to assist with the interpretation of the tests are contained within Appendix B. The types and numbers of tests carried out are detailed in the following table. The significance of the results is discussed further in Section 3. Table 1. Geotechnical testing

Type of test No. of samples tested

Moisture Content 4

Atterberg Limits 4

Water Soluble sulphate and pH 5

Report No: LW23258


2.4 Ground Conditions

2.4.1 Stratigraphy

2.4.1.1 Surface Covering

Borehole BH1 was progressed through a 50mm layer of wood chippings over a geotextile. Boreholes BH2 and BH3 were excavated through a layer of topsoil some 100mm in thickness. At the location of borehole BH4, a 150mm thick layer of asphalt overlying 100mm of granular sub base was present.

2.4.1.2 Made Ground

Beneath the surfacing materials, each of the boreholes passed downwards through made ground, comprising clay and gravel containing a variable proportion of flint, brick, clinker, charcoal and siltstone/ sandstone, to depths of between 0.25m (BH2) and 1.9m (BH4) below ground level. The thickness of the made ground was greatest in the south western corner of the site.

2.4.1.3 Tunbridge Wells Sand Formation

Underlying the made ground, the boreholes progressed into undisturbed silt and clay deposits that continued to the full depth of the investigation at 3m below ground level. Within boreholes BH1 and BH2, the clay and silt deposits were noted to be soft or loose to depths of 2.0m and 1.7m below ground level, respectively. Beneath these depths, and below the made ground recorded in boreholes BH3 and BH4, the undisturbed soils were noted to comprise firm to stiff or stiff clay or medium dense silt. These soils are considered to represent the Tunbridge Wells Sand Formation deposits indicated on the published geological map.

2.4.1.4 Ground water and Stability

Groundwater stood at depths of between 0.5m and 1.07m below ground level on completion of the boreholes. Instability of the granular soils associated with the ingress of groundwater was noted in the boreholes.

Report No: LW23258


3. GEOTECHNICAL ASSESSMENT

It is proposed to construct a new nursery with associated play areas at the site. At the time of writing, no details were available concerning the loads likely to be applied to the foundations.

3.1.1 Soil Shrinkage/Heave Potential

The soils of the Tunbridge Wells Sand Formation have been classified as clays of low to intermediate plasticity and with plasticity indices in the range of 8% to 19% the soils may be expected to be either non plastic or to exhibit a low volume change potential. It is recommended that precautions against shrinkage and heave for any foundation system constructed within the Tunbridge Wells Sand Formation should assume a low volume change potential and take into account current guidance such as that given by the National House Builders Council (NHBC). Whilst this report has been prepared to provide advice to assist designers in undertaking detailed design, the report itself does not represent a detailed design statement. All detailed foundation design including assessment of minimum founding depths for spread foundations and requirements for placement of void formers must take into account the volume change potential of the soil and the presence of trees (previous, present and proposed). It is strongly recommended that a detailed arboricultural survey should be undertaken for the site. The survey should be extended to include a review of historical photographs and detailed site plans (if available) to establish the species and location of any felled trees that may affect foundation design. The information obtained from the arboricultural survey, information on proposed planting schemes and the findings of this report should be provided to the structural engineers responsible for design of foundation systems.

3.1.2 Spread Foundations

Any made ground should be regarded as potentially variable in nature and state of compaction and, as such, unsuitable as a founding medium for shallow footings. New footings should be constructed below the made ground and any soils disturbed by the construction or removal of any previously existing foundations and services. Attention is drawn to borehole BH4 where the made ground was recorded to extend to a depth of 1.9m below ground level. Similarly, the soft clay and loose silt present within boreholes BH1 and BH2 to depths of 1.7m and 2.0m should be assumed to be unsuitable as a bearing medium and foundations should be extended to bear beneath such soils where present at formation depth. For design purposes, a net allowable bearing capacity of 150kN/m

2 may be

assumed for the construction of spread (pad or strip) foundations up to 1.0m

Report No: LW23258


across bearing within the firm-to-stiff or better clay or medium dense silt of the Tunbridge Wells Sand Formation. The quoted bearing capacity is expected to limit settlement to less than 25mm. Subject to any precautions required to protect against the effects of soil shrinkage or heave caused by trees, a minimum depth to formation of 0.75m should be adopted. It is noted that in view of the silty nature of the soils and the presence of groundwater at shallow depth there may be practical constraints in constructing spread foundations in these materials. Where foundations cross between soil boundaries, they should be suitably reinforced to minimise the potential for cracking to occur due to differential settlement.

3.1.3 Piled Foundations

It is considered that the undisturbed Tunbridge Wells Sand Formation soils are likely to be suitable for supporting the proposed structure on piled foundations. However, further investigation in the form of cable percussion boreholes would be required to provide soil parameters for pile design.

3.2 Groundwater

Groundwater depths of between 0.5m and 2.8m below ground level were recorded on completion of the boreholes, with the water rising to stand at depths of 0.5m to 0.9m below ground level after a short observation period. Excavations beneath the water table, and particularly through coarse grained soils, are likely to require positive drainage to maintain adequately dry working conditions and excavation stability. The soils in the bases of excavations extending even a short distance below the water table would be expected to soften rapidly under the effects of water seepage. The potential for ‘running sand’ conditions to develop should not be overlooked. If encountered above the standing water table, it would be expected that the ingress of groundwater or surface runoff should be adequately managed by pumping from sumps.

3.3 Stability of Excavations

All excavations should be assumed to be prone to short term instability and excavations below the water table are likely to be problematic without positive groundwater control, as discussed above, and suitable support. Where personnel access is required to any excavation its stability should be assessed by a suitably qualified and experienced responsible person. Entry into

Report No: LW23258


unsupported excavations should only be permitted. where they have been assessed as safe to enter but in any case it is advised that personnel access to unsupported excavations greater than 1.2m depth should be prohibited. Particular attention must be paid to ensuring the stability of nearby structures as well as the adjacent car park.

3.4 Aggressivity to Concrete

In consideration of the depth of made ground soils encountered beneath the site it is recommended that ‘brown field conditions’ should be assumed for the purpose of assessing the aggressivity of the chemical environment for concrete classification (ACEC class). Given the noted occurrence of groundwater seepages, ‘mobile groundwater’ conditions should also be assumed. Chemical analysis of the soil indicates a sulphate content falling into Design Sulfate Class DS-1 of Table C2 of the Building Research Establishment Special Digest No 1 “Concrete in aggressive ground”, 2005. The results of the pH tests indicate that the underlying soils are acidic. In accordance with the BRE digest, a DS-1 Design Sulfate Class and an AC-3z ACEC classification should be assumed as a minimum for the design of concrete in contact with the ground.

3.5 Ground Floors

In view of the variable thickness of made ground and soft/ loose soils present beneath the site, it is recommended that ground floors for all sensitive structures should be suspended.

3.6 Pavement Design

In situ TRL cone penetrometer tests for the direct estimation of California bearing ratio indicated CBR values ranging between 3% and >10% in the underlying made ground and Tunbridge Wells Sand Formation soils. The former Department of the Environment, Transport and the Regions Design Manual for Roads and Bridges, Volume 7 (Pavement Design & Maintenance), Section 2, Part 2 1994 provides a useful correlation between soil type and equilibrium (long term) CBR values. This guidance suggests a design equilibrium CBR value of 1.5% to 4% would be applicable to the undisturbed soils for the construction of thin pavement under average construction conditions and assuming a high groundwater table. Based upon review of the in-situ test results and the quoted guidance it is suggested that for both the made ground and Tunbridge Wells Sand Formation soils a CBR value of 3% may be adopted for pavement design.

Report No: LW23258


All formations should be proof rolled and any very loose, bulky, soft, degradable or otherwise unsuitable materials thus identified should be removed and replaced with well compacted coarse grained fill. Prepared subgrades should be protected from severe adverse weather by ensuring they are graded to falls to prevent ponding, and they should be reasonably protected from trafficking during construction. The subgrade should be assumed to be susceptible to frost heave. If new roads/ parking areas are to be adopted the local highway authority should be consulted with reference to the acceptability of the proposed design figures prior to designs being finalised and construction undertaken.

3.7 Drainage

Trial Pit Falling Head Soakage Testing In situ soakage testing was carried out adjacent to boreholes BH2 and BH3. At both positions the water level within the test pit rose over the course of the monitoring period to stand some 150mm and 120mm below ground level on completion. It is noted that the weather was very wet at the time of the investigation and these shallow tests may have been affected by surface runoff. Borehole Falling Head Soakage Testing In situ soakage testing was also undertaken within boreholes BH2 and BH3 in accordance with ‘The Soakaway Design Guide’ published by Kent County Council (July 2000). From the results of the tests, calculations were made in accordance with the guide to estimate the infiltration rate that could be expected for soakaways constructed to discharge into the underlying soils within the test zone. No significant soakage was recorded from the test carried out in borehole BH2.

The following infiltration rate was derived from the test carried out in borehole BH3:

BH3 f = 2.6 x 10-6 m/s under 1.3m head of water assumed

The value ‘f’ is equivalent to the soil infiltration coefficient ‘q’ quoted in the Construction Industry Research and Information Association (CIRIA) Report 156. In view of the low infiltration rates recorded it appears that the Tunbridge Wells Sand Formation soils are unlikely to be suitable for discharging surface water to the ground via soakaways. It is also noted that in view of the very shallow water level recorded it is unlikely that sufficient storage would be available for the construction of conventional soakaways at the site.

Report No: LW23258


4. CONCLUSIONS

The following conclusions present a summary of the main findings of the investigation. However, no reliance should be placed on any point of the conclusions until the whole of the report has been read as other sections of the report may put into context the information contained herein.

The ground investigation confirmed the soils beneath the site to comprise a variable depth of made ground (0.25m to 1.9m) overlying clay and silt of the Tunbridge Wells Sand Formation. Soft/ loose soils were recorded to extend to a depth of 2.0m to 1.7m within boreholes BH1 and BH2, respectively.

Groundwater was recorded to stand at depths of between 0.5m and 0.9m after a short observation period following completion of the boreholes.

It is recommended that precautions against shrinkage and heave for any foundation system constructed within the Tunbridge Wells Sand Formation should assume a low volume change potential and take into account current guidance such as that given by the National House Builders Council (NHBC).

A net allowable bearing capacity of 150kN/m2 may be assumed for the design

of spread (pad or strip) foundations up to 1.0m across bearing within the firm-to-stiff, or better, clay or medium dense silt of the Tunbridge Wells Sand Formation. It is noted that made ground and/ or soft/ loose soils were recorded to extend to depths of up to 2m below ground level and allowance should be made for foundations to bear below these suspect and/or weak soils.

Excavations beneath the water table, and particularly through the silty and granular soils, are likely to require positive drainage to maintain adequately dry working conditions and excavation stability. The potential for ‘running sand’ conditions to develop should not be overlooked.

Entry into unsupported excavations should only be permitted where they have been assessed as safe to enter but in any case it is advised that personnel access to unsupported excavations greater than 1.2m depth should be prohibited.

In accordance with the BRE digest, a DS-1 Design Sulfate Class and an AC-3z ACEC classification should be assumed as a minimum for the design of concrete in contact with the ground at the site.

Report No: LW23258


In view of the variable thickness of made ground and soft/ loose soils beneath the site, it is recommended that ground floors should be suspended.

Based upon review of the in-situ test results and the quoted guidance it is suggested that for the made ground and Tunbridge Wells Sand Formation soils a CBR value of 3% may be adopted for pavement design. The subgrade should be assumed to be susceptible to frost heave.

It is unlikely that the Tunbridge Wells Sand Formation soils will be suitable for discharging surface water to ground via soakaways.

Ashdown Site Investigation Limited

November 2012

Report No: LW23258

APPENDIX A Exploratory Hole Notes Exploratory Hole Records DPSH Profiles TRL Profiles Summary of Borehole Falling Head Soakage Test Results Summary of Trial Pit Falling Head Soakage Test Results

NOTES FOR THE INTERPRETATION OF EXPLORATORY HOLE RECORDS

1 Symbols and abbreviations Samples U ‘Undisturbed’ Sample: - also known as ‘U100’ or ‘U4’ - 100mm diameter by 450mm long. The

number of blows to drive in the sampling tube is shown after the test index letter in the SPT column.

Uo Sample not obtained. U* Full penetration of sample not obtained. U** Full penetration obtained but limited sample recovered. Pi Piston Sample: ‘Undisturbed’ sample 100mm diameter by 600mm long. D Disturbed Sample. R Root Sample. B Bulk Disturbed Sample. W Water Sample. J Jar Sample (sample taken in amber glass jar fitted with gas tight lid) T Tub Sample E Environmental Suite (including a jar sample, tub sample and vial sample) In situ Testing S Standard penetration test (SPT): In the borehole record the depth of the test is that at the start

of the normal 450mm penetration, the number of blows to achieve the standard penetration of 300mm (the ‘N’ value) is shown after the test index letter, but the seating blows through the initial 150mm penetration are not reported unless the full penetration of 450mm cannot be achieved. In the latter case, the symbols below are added to the test index letter:-

S* Seating blows only S** Blow count includes seating blows S++ No penetration So ‘Split spoon’ SPT sampler sank under its own weight.

The test is usually completed when the number of blows reaches 50 (25 blows for seating count). The depths of both the top and bottom of the test drive are shown in the sample column on the Borehole Record. If a sample is not recovered in the sampler, a disturbed sample is over the depth of the test as boring continues.

C Standard Penetration Test (SPT) conducted usually in coarse grained soils or weak rocks using the same procedure as for the SPT but with a 50mm diameter, 60º apex solid cone fitted in place of the sampler. Variations in test results are indicated by the same symbols as for the SPT (above).

V Shear Vane Test: Undrained shear strength (cohesion) (kN/m2) shown within the Vane/Pen

Test and N Value column. H Hand penetrometer Test: Undrained shear strength (cohesion) (kN/m2) shown within the

Vane/Pen Test and N Value column. P Perth Penetrometer Test: See Insitu Testing Notes in Appendix C for full description. Number

of blows for 300mm penetration shown under Vane/Pen Test and N Value column. In sand the number of blows is approximately equivalent to the SPT "N" value.

2 Soil Description Description and classification of soils has been carried out using as a general basis the British Standard Geotechnical investigation and testing – Identification and classification of soil, Part 1 Identification and description (BS EN ISO 14688-1:2002) and Part 2 Principles of classification (BS EN 14688-2:2004). Fine Grained Soils The consistency of fine grained soils given in the report is based on visual inspection of the samples and the strength is based on results of in situ and/or laboratory undrained shear strength tests when carried out. The consistency is determined on the following basis:

Consistency Manual Test

Very Soft Soil exudes between fingers when squeezed in hand Soft Soils can be moulded by light finger pressure Firm Cannot be moulded by finger but rolled to 3mm threads

without breaking/crumbling Stiff Crumbles/breaks when rolled to 3mm thick threads but

can be moulded into a lump again Very Stiff Cannot be moulded and crumbles under pressure, can

be indented by thumbnail Based on BS EN ISO 14688-1:2002 The terms used for the designation of the undrained shear strength are as follows:

Undrained Shear Strength

Extremely to Very Low <20 kPa Low 20-40 kPa Medium 40-75 kPa High 75-150 kPa Very High 150-300 kPa Extremely high 300-600 kPa

Based on BS EN ISO 14688-2:2004 Note: The undrained shear strength of the soils is measured either by laboratory testing or in the field using hand penetrometer or shear vane. It is recognised that any coarse grained soil that has in excess of approximately 35% fine grained soil (clay and silt) can often be expected to behave as a fine grained soil despite the dominance of coarse grained material within the soil mass. To reflect this, it is the soil type that dominates the behaviour of the soil mass that appears on the exploratory hole records. Coarse Grained Soils The relative densities of coarse grained soils (sand and gravel) given in the report are based on field estimations and the results of the Standard Penetration Test (SPT) and equivalent correlation from other testing. The classification in terms of "N" Values is as follows:

SPT ‘N’ Value Relative Density

0-4 Very Loose 4-10 Loose 10-30 Medium Dense 30-50 Dense Greater than 50 Very Dense

3 Rock Description Description and classification of rocks has been carried out using as a general basis the British Standard Geotechnical investigation and testing – Identification and classification of rock, Part 1 Identification and classification (BS EN ISO 14689-1:2003). The description of rock mass includes the type of rock, structure, discontinuities and weathering. The unconfined compressive strength of rock material is determined on the following basis: Term Field Identification Unconfined

Compressive Strength (MPa)

Extremely Weak Indented by thumbnail Less than 1 Very Weak Crumbles under firm blows with point of geological

hammer, peeled by pocket knife 1 to 5

Weak Peeled by pocket knife with difficulty, shallow indentations made by firm blow with geological hammer

5 to 25

Medium Strong Cannot be peeled or scraped with knife, can be fractured with single firm blow of geological hammer

25 to 50

Strong Requires more than one blow of geological hammer to fracture

50 to 100

Very Strong Requires may blows of geological hammer to fracture it

100 to 250

Extremely Strong Can only be chipped with geological hammer

Greater and 250

The terms describing discontinuity and bedding spacing are as follows: Bedding Thickness Very Thick >2000mm

Discontinuity Spacing Very Wide >2000mm

Thick 2000-600mm Medium 600-200mm Thin 200-60mm Very Thin 60-20mm Thickly Laminated 20-6mm Thinly Laminated <6mm

Wide 2000-600mm Medium 600-200mm Close 200-60mm Very Close 60-20mm Extremely Close <20mm

Chalk Chalk description is based on BS EN ISO 14688 and BS EN ISO 14689. The classification of chalk generally follows the guidance offered by the Construction Industry Research and Information Association (CIRIA) C574, ‘Engineering in Chalk’. This is based on assessment of chalk density, discontinuity and aperture spacing, and the proportion of intact chalk to silt of chalk. See additional chalk classification notes.

Borehole No.:

Site Name:

Job No.:

Start Date: End Date:

Excavation Method:

Borehole Diameter:

Made By:

Swanborough FarmSwanborough

Lewes, East SussexBN7 3PF

Samples and Testing Strata

StandpipeInstallation

SampleType

From(m)

To(m)

Vane/ PenTest

N Value

DPSH ProfileBlows/100mm

LegendDepth /

ReducedLevel

Strata Descriptions

Remarks:

Depths

BH1

King Offa Nursery, Bexhill, East Sussex

LW23258

02/11/2012 02/11/2012

J

J

D

J

D H

D

H

D

0.10

0.40

0.50

0.70

0.90

1.50

2.50

3.00

<25

>250

5 15 25

0.00

0.15

0.60

1.20

2.00

3.00

Ground Level

Wood chippings with geotextile at base (50mm) over,MADE GROUND: Black fine to coarse gravel of flint, clinkerand brick.

MADE GROUND: Orange brown and brown mottled slightlygravelly silty clay. Gravel is fine charcoal.

Soft orange brown and blue grey mottled very silty CLAY withoccasional black iron staining. (Tunbridge Wells SandFormation)

becoming very stiff below 1.0m depth.

Loose red brown slightly clayey gravelly SILT with occasionalthin beds of stiff light grey and light orange brown clay. Gravelis fine to medium siltstone/ ironstone. (Tunbridge Wells SandFormation)

Very stiff light grey and light orange brown mottled silty CLAYwith occasional black iron staining and thin beds of weaksiltstone. (Tunbridge Wells Sand Formation)

End of Borehole

Dynamic Sampler

Various

TH

Standing water level at 0.5m depth on completion of borehole.

Borehole collapsed below 2.5m depth.

Dynamic probe carried out adjacent to borehole.

Borehole No.:

Site Name:

Job No.:


Excavation Method:

Borehole Diameter:

Made By:





SampleType

From(m)

To(m)

Vane/ PenTest

N Value


LegendDepth /

ReducedLevel

Strata Descriptions

Remarks:

Depths

BH2


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02/11/2012 02/11/2012

J

J

D H

D

D

D

H

D

0.20

0.30

0.50

1.00

1.50

2.20

2.90

3.00

80

>250

5 15 25

0.00

0.10

0.25

0.70

1.70

2.70

3.00

Ground Level

Topsoil.

MADE GROUND: Brown slightly gravelly silty clay. Gravel isfine to medium flint, clinker and brick.

Firm to stiff orange brown silty CLAY with occasional greystaining. (Possible Made Ground/ Tunbridge Wells SandFormation)

Loose orange brown and light grey clayey SILT with partings offine gravel of ironstone. (Possible Made Ground/ TunbridgeWells Sand Formation)

with a 50mm thick layer of fine to medium sand at 1.3m depth.

Medium dense orange brown and light grey mottled clayeySILT. (Tunbridge Wells Sand Formation)

Very stiff grey brown and orange brown mottled silty CLAY.(Tunbridge Wells Sand Formation)

End of Borehole

Dynamic Sampler

Various

TH

Hand dug trial pit (0.2m x 0.2m in plan) excavated adjacent to borehole to a depth of0.5m.

Water level at 2.8m depth on completion of borehole rising to 1.07m after 30 minutes.

Borehole stable on completion.


Borehole No.:

Site Name:

Job No.:


Excavation Method:

Borehole Diameter:

Made By:





SampleType

From(m)

To(m)

Vane/ PenTest

N Value


LegendDepth /

ReducedLevel

Strata Descriptions

Remarks:

Depths

BH3


LW23258

02/11/2012 02/11/2012

J

D

J

D H

D

0.20

0.50

0.80

0.90

2.00

>250

5 15 25

0.00

0.10

0.70

1.50

2.00

Ground Level

Topsoil.

MADE GROUND: Light brown, orange brown and red brownmottled silty clay with pockets of fine to coarse gravel of brick,roadstone, flint, clinker and sandstone.

Very stiff light orange brown silty CLAY. (Tunbridge WellsSand Formation)

Medium dense orange brown and occasionally light greymottled SILT. (Tunbridge Wells Sand Formation)grading into very dense SILT/ extremely weak SILTSTONEbelow 1.6m depth.

End of Borehole

Dynamic Sampler

Various

TH

Hand dug trial pit (0.3m x 0.3m in plan) excavated adjacent to borehole to a depth of0.5m.

No further progress below 2.0m depth - too dense.

Water level at 1.7m depth on completion of borehole, rising to 1.0m after 30 minutes.

Borehole stable on completion.


Borehole No.:

Site Name:

Job No.:


Excavation Method:

Borehole Diameter:

Made By:





SampleType

From(m)

To(m)

Vane/ PenTest

N Value


LegendDepth /

ReducedLevel

Strata Descriptions

Remarks:

Depths

BH4


LW23258

02/11/2012 02/11/2012

J

J

D

J

H

D

D

J

J

D H

DH

0.30

0.40

0.50

0.60

0.80

0.90

1.50

1.70

2.00

2.50

3.00

65

170

225

5 15 25

0.00

0.25

0.35

0.45

1.90

3.00

Ground Level

Asphalt (150mm) over,Fine to coarse gravel of roadstone (sub base).

MADE GROUND: Dark brown grey silty gravelly clay. Gravel isfine to coarse brick, clinker and flint.

MADE GROUND: Grey brown silty clay with black organicspeckling.

MADE GROUND: Light orange brown and light grey slightlygravelly silty clay with black iron staining. Gravel is fine tomedium siltstone.becoming soft below 1.0m depth.

with fine to medium fragments of brick below 1.7m depth.

Stiff light brown and grey mottled CLAY with partings of lightcream silt. (Tunbridge Wells Sand Formation)

End of Borehole

Dynamic Sampler

Various

TH

Standing water level at 0.9m depth on completion of borehole.

Borehole collapsed to 1.2m depth on completion.


ASHDOWN SITE INVESTIGATION LTD

SITE King Offa Nursery, Bexhill, East Sussex Report Ref. LW23258

DP No. BH1

Depth (m) Blows Torque (kgm)

0.00

0.10

0.20

0.30 1

0.40 1

0.50 0

0.60 0

0.70 0

0.80 0

0.90 0

1.00 0

1.10 1

1.20 0

1.30 1

1.40 2

1.50 1

1.60 2

1.70 3

1.80 3

1.90 2

2.00 2

2.10 2

2.20 3

2.30 3

2.40 2

2.50 3

2.60 1

2.70 3

2.80 3

2.90 3

3.00 4

3.10 4

3.20 4

3.30 5

3.40 4

3.50 5

3.60 6

3.70 5

3.80 4

3.90 5

4.00 6

4.10 6

4.20 6

4.30 7

4.40 6

4.50 7

4.60 8

4.70 10

4.80 10

4.90 10

5.00 10

Comments

DPSH Continuous Dynamic Probe N100 vs Depth Profile

0.00

1.00

2.00

3.00

4.00

5.00

0 10 20 30

Dep

th (

m)

Blowcount per 100mm



DP No. BH2


0.00

0.10

0.20 1

0.30 2

0.40 2

0.50 1

0.60 1

0.70 1

0.80 1

0.90 1

1.00 1

1.10 1

1.20 1

1.30 2

1.40 3

1.50 3

1.60 3

1.70 3

1.80 3

1.90 5

2.00 5

2.10 4

2.20 5

2.30 4

2.40 6

2.50 6

2.60 5

2.70 5

2.80 4

2.90 5

3.00 4

3.10 5

3.20 5

3.30 5

3.40 7

3.50 6

3.60 8

3.70 7

3.80 8

3.90 8

4.00 7

4.10 7

4.20 10

4.30 10

4.40 10

4.50 7

4.60 7

4.70 6

4.80 8

4.90 8

5.00 8

Comments


0.00

1.00

2.00

3.00

4.00

5.00

0 10 20 30

Dep

th (

m)

Blowcount per 100mm



DP No. BH3


0.00

0.10

0.20 1

0.30 1

0.40 1

0.50 2

0.60 2

0.70 1

0.80 3

0.90 3

1.00 4

1.10 4

1.20 3

1.30 3

1.40 3

1.50 5

1.60 6

1.70 7

1.80 9

1.90 9

2.00 11

2.10 12

2.20 11

2.30 12

2.40 10

2.50 8

2.60 8

2.70 9

2.80 12

2.90 12

3.00 11

3.10 9

3.20 9

3.30 9

3.40 11

3.50 12

3.60 12

3.70 11

3.80 9

3.90 7

4.00 6

4.10 7

4.20 6

4.30 6

4.40 6

4.50 5

4.60 5

4.70 4

4.80 7

4.90 7

5.00 7

Comments


0.00

1.00

2.00

3.00

4.00

5.00

0 10 20 30

Dep

th (

m)

Blowcount per 100mm



DP No. BH4


0.00

0.10

0.20 10

0.30 5

0.40 2

0.50 1

0.60 0

0.70 1

0.80 0

0.90 1

1.00 1

1.10 2

1.20 1

1.30 2

1.40 1

1.50 1

1.60 2

1.70 1

1.80 3

1.90 3

2.00 2

2.10 3

2.20 3

2.30 2

2.40 3

2.50 4

2.60 3

2.70 3

2.80 4

2.90 4

3.00 4

3.10 4

3.20 5

3.30 6

3.40 6

3.50 5

3.60 7

3.70 7

3.80 7

3.90 7

4.00 7

4.10 7

4.20 7

4.30 8

4.40 7

4.50 8

4.60 8

4.70 9

4.80 10

4.90 10

5.00 10

Comments


0.00

1.00

2.00

3.00

4.00

5.00

0 10 20 30

Dep

th (

m)

Blowcount per 100mm

SITE Report Ref. LW23258

Test Location Reference BH1

Depth of Start of Test (mbgl) 0.00

No. Blows Total

Blows

Reading

(mm)

Depth

(mbgl)

DCP Zero Reading 77 0.00

1 1 184 0.11 2 0.05 2

1 2 213 0.14 9 0.12 9

1 3 281 0.20 3 0.17 3

1 4 362 0.29 3 0.24 3

1 5 446 0.37 3 0.33 3

1 6 509 0.43 4 0.40 4

1 7 560 0.48 5 0.46 5

1 8 606 0.53 5 0.51 5

1 9 647 0.57 6 0.55 6

1 10 686 0.61 6 0.59 6

1 11 722 0.65 7 0.63 7

1 12 758 0.68 7 0.66 7

1 13 792 0.72 7 0.70 7

1 14 823 0.75 8 0.73 8

1 15 854 0.78 8 0.76 8

1 16 883 0.81 9 0.79 9

1 17 909 0.83 10 0.82 10

1 18 934 0.86 10 0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

0.84 10

Notes: CBR Value calculated in accordance with the TRRL equation given in TRL Road Note 8.

AverageD

epth

(mbgl)

CBR%CBR%


TRL Dynamic Cone Penetrometer Record


0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

1.10

1.20

1.30

1.40

1.50

1.60

1.70

1.80

1.90

2.00

0 20 40 60 80 100 120

De

pth

(m

bgl

)

CBR (%)




No. Blows Total

Blows

Reading

(mm)

Depth

(mbgl)


1 1 143 0.07 3 0.04 3

1 2 209 0.14 4 0.11 4

1 3 232 0.16 11 0.15 11

1 4 238 0.17 45 0.16 45

2 6 257 0.19 28 0.18 28

2 8 281 0.21 22 0.20 22

1 9 292 0.22 24 0.22 24

1 10 305 0.23 20 0.23 20

1 11 318 0.25 20 0.24 20

1 12 332 0.26 19 0.25 19

1 13 348 0.28 16 0.27 16

1 14 362 0.29 19 0.28 19

1 15 376 0.31 19 0.30 19

1 16 390 0.32 19 0.31 19

1 17 404 0.33 19 0.33 19

1 18 419 0.35 17 0.34 17

1 19 432 0.36 20 0.35 20

1 20 444 0.37 22 0.37 22

2 22 467 0.40 23 0.38 23

2 24 487 0.42 26 0.41 26

2 26 503 0.43 34 0.42 34

2 28 517 0.45 39 0.44 39

2 30 533 0.46 34 0.45 34

2 32 549 0.48 34 0.47 34

2 34 569 0.50 26 0.49 26

2 36 587 0.52 30 0.51 30

2 38 616 0.55 18 0.53 18

2 40 662 0.59 11 0.57 11

1 41 705 0.63 6 0.61 6

1 42 745 0.67 6 0.65 6

1 43 778 0.71 7 0.69 7

1 44 805 0.73 9 0.72 9

1 45 835 0.76 8 0.75 8

1 46 864 0.79 9 0.78 9

1 47 892 0.82 9 0.81 9

1 48 919 0.85 9 0.83 9

1 49 953 0.88 7 0.87 7

0.87 7

0.87 7

0.87 7

0.87 7

0.87 7

0.87 7

0.87 7

0.87 7

0.87 7

0.87 7

0.87 7

0.87 7

0.87 7

0.87 7

0.87 7

0.87 7

0.87 7


AverageD

epth

(mbgl)

CBR%CBR%




0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

1.10

1.20

1.30

1.40

1.50

1.60

1.70

1.80

1.90

2.00

0 20 40 60 80 100 120

De

pth

(m

bgl

)

CBR (%)




No. Blows Total

Blows

Reading

(mm)

Depth

(mbgl)


1 1 152 0.08 3 0.04 3

1 2 231 0.16 3 0.12 3

1 3 294 0.22 4 0.19 4

1 4 331 0.26 7 0.24 7

1 5 360 0.29 9 0.27 9

1 6 383 0.31 11 0.30 11

1 7 407 0.34 10 0.32 10

1 8 429 0.36 12 0.35 12

1 9 458 0.39 9 0.37 9

1 10 491 0.42 7 0.40 7

1 11 519 0.45 9 0.43 9

1 12 558 0.49 6 0.47 6

1 13 597 0.53 6 0.51 6

1 14 623 0.55 10 0.54 10

1 15 637 0.57 19 0.56 19

1 16 654 0.58 15 0.57 15

1 17 668 0.60 19 0.59 19

1 18 684 0.61 16 0.60 16

1 19 701 0.63 15 0.62 15

1 20 717 0.65 16 0.64 16

1 21 731 0.66 19 0.65 19

1 22 747 0.68 16 0.67 16

1 23 760 0.69 20 0.68 20

1 24 775 0.70 17 0.70 17

1 25 788 0.72 20 0.71 20

1 26 801 0.73 20 0.72 20

1 27 812 0.74 24 0.73 24

1 28 824 0.75 22 0.75 22

1 29 836 0.76 22 0.76 22

1 30 847 0.78 24 0.77 24

1 31 856 0.78 30 0.78 30

1 32 868 0.80 22 0.79 22

1 33 879 0.81 24 0.80 24

1 34 889 0.82 26 0.81 26

1 35 900 0.83 24 0.82 24

1 36 912 0.84 22 0.83 22

1 37 923 0.85 24 0.85 24

1 38 934 0.86 24 0.86 24

0.86 24

0.86 24

0.86 24

0.86 24

0.86 24

0.86 24

0.86 24

0.86 24

0.86 24

0.86 24

0.86 24

0.86 24

0.86 24

0.86 24

0.86 24

0.86 24


AverageD

epth

(mbgl)

CBR%CBR%




0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

1.10

1.20

1.30

1.40

1.50

1.60

1.70

1.80

1.90

2.00

0 20 40 60 80 100 120

De

pth

(m

bgl

)

CBR (%)

ASHDOWN SITE INVESTIGATION LIMITED

Site: King Offa Nursery, Bexhill, East Sussex Report No.: Sheet No.:

LW23258 1 of 1

SUMMARY OF BOREHOLE FALLING HEAD SOAKAGE TEST RESULTS

Borehole BH2

Borehole BH3

Time (mins)

Depth to water (m)

Time (mins)

Depth to water (m)

0 0.00* 0 0.15* 1 0.03 1 0.16 2 0.05 10 0.21

40 0.23 47 0.32 57 0.23 115 0.36 101 0.24 170 0.24

Borehole Depth (m)

3.00 Borehole

Depth (m)

2.00

Casing Depth (m)

1.00 Casing

Depth (m)

1.00

Borehole Diameter (mm)

92.00 Borehole

Diameter (mm)

92.00

Casing Diameter (mm)

105.00 Casing

Diameter (mm)

105.00

Remarks:

* Standing water depth at 1.07m in BH2 and at 1.00m in BH3 at start of soakage.

ASHDOWN SITE INVESTIGATION LIMITED

Site: King Offa Nursery, Bexhill, East Sussex Report No.: Sheet No.:

LW23258 1 of 1

SUMMARY OF TRIAL PIT FALLING HEAD SOAKAGE TEST RESULTS

Trial Pit BH2

Trial Pit BH3

Time (mins) Depth to

water (m bgl)

Time (mins) Depth to

water (m bgl) 0 0.22 0 0.20* 1 0.22 3 0.20 2 0.23 5 0.20 5 0.23 15 0.20 45 0.20 62 0.17 62 0.19 130 0.12 106 0.17 175 0.15

Pit Length - 0.20m Pit Width - 0.20m

Pit Depth - 0.50m bgl

Pit Length - 0.30m Pit Width - 0.30m

Pit Depth - 0.50m bgl Remarks:

bgl - below ground level. * Standing water depth at 0.4m at start of test.

Report No: LW23258

APPENDIX B Geotechnical Laboratory Testing Notes

Laboratory Test Results

of 2

GEOTECHNICAL LABORATORY TESTING NOTES

1 Index Tests Index (Atterberg Limit) tests are undertaken on samples of fine grained soils provide the primary information for the classification of fine grained soils. Fine grained soil is tested to determine its liquid and plastic limits, which are moisture contents that define boundaries between material consistency states. These tests are used to evaluate indices used for soil identification and to help determine the shrinkage and swelling characteristics of the soil under conditions of changing moisture content. The tests are carried out in accordance with BS1377: Part 2: 1990 + A1:1996 Classification tests. The consistency index is derived from the Index Tests and is summarized in the following table. These divisions may be approximate, particularly for low plasticity soils. Consistency Consistency Index Very Soft <0.25 Soft 0.25 to 0.50 Firm 0.50 to 0.75 Stiff 0.75 to 1.00 Very Stiff >1.00

Based on BN EN ISO 14688-2:2004

2 Particle Size Distribution Tests Sieve analyses are carried out soil samples to establish their particle size distribution that can assist in the assessment of the permeability and classification of granular soils. The tests are carried out in accordance with BS1377: Part 2: 1990 + A1:1996 Classification tests.

3 Natural Moisture/ Saturated Moisture Content Determination of Chalk The results of natural moisture or saturated moisture content tests of disturbed samples of chalk are used to assist in the classification of the chalk to determine key geotechnical parameters of strength, density and crushing properties. The tests are carried out in accordance with BS1377: Part 2: 1990 + A1:1996 Classification tests.

4 Soil Suction Testing Soil suction tests are undertaken for the determination of the state of desiccation in clay soils. The testing is carried out in accordance with the Building Research Establishment Information Paper IP4/93, dated February 1993.

5 Triaxial Compression Tests Undrained triaxial compression tests are carried out on undisturbed samples of cohesive soil in order to assist in the determination of the undrained shear strength of the soil. The results of moisture content and density determinations are also included. The tests are carried out in accordance with BS1377: Part 7: 1990 + A1:1994 Shear strength tests (total stress).

6 Shear Vane and Hand Penetrometer Testing Undisturbed samples are tested in the laboratory using a Geonor Hand Shear Vane for the determination of their undrained shear strength.

of 2

The vane tests are carried out in general accordance with BS1377: Part 7: 1990 + A1:1994 Shear strength tests (total stress).

7 One Dimensional Consolidation Tests One-dimensional consolidation tests are performed on undisturbed soil samples to ascertain their settlement characteristics. The tests are carried out in accordance with BS1377: Part 5: 1990 + A1:1994 Compressibility, Permeability and Durability tests.

8 Dry Density / Moisture Content Relationship (Compaction) Testing Compaction testing for the determination of the dry density / moisture content relationship is carried out on using either a 2.5kg, 4.5kg hammer or a vibrating hammer. The tests are carried out in accordance with the British Standard BS1377: Part 4: 1990 + A1 & A2:2002 Compaction-related tests.

9 California Bearing Ratio The soil is usually compacted at the as dug “natural” moisture content and often at moisture contents around the natural moisture content. The California bearing ratio is determined in accordance with the British Standard BS1377: Part 4: 1990 + A1 & A2:2002 Compaction related tests.

10 Chemical Testing Soil samples are tested for their concentration of water soluble sulphate and pH for use in concrete mix design. Water samples are tested for total sulphate concentration and pH value. Where a water soluble sulphate content in soils or a total sulphate content in groundwater exceeds 3000mg/l SO4 the magnesium sulphate content of the samples is required to be determined (BRE Special Digest 1:2005).


Site:

King Offa Nursery, Bexhill, East Sussex Report No:

Sheet No: LW23258 1 of 1

SOIL CLASSIFICATION SUMMARY

Sample

No. Depth ( m )

Nat. Moist. Cont. (w %)

Equiv. Moist. Cont. (wa %)

Atterberg Limits Class'n Cons.Index

(Ic )

% passing 425 µm sieve

Visual Description of Sample

Wl

% Wp

% Ip

%

BH1 3.00 17 17 29 17 12 CL 0.99 100 Stiff brown and light grey slightly sandy

CLAY with thin partings of dark orange sandstone.

BH2 3.00 15 15 24 16 8 CL 1.12 100 Very stiff grey mottled grey brown slightly

sandy CLAY.

BH3 0.90 14 14 38 19 19 CI 1.26 100 Very stiff yellow brown silty CLAY.

BH4 2.50 18 18 33 19 14 CL 1.08 100 Very stiff brown mottled light brown and grey silty CLAY.

Remarks:

Unit A2

Windmill Road

Ponswood Industrial Estate

St Leonards on Sea

East Sussex

TN38 9BY

Telephone (01424) 718618

Facsimile (01424) 729911

THE ENVIRONMENTAL LABORATORY LTD

F.A.O. David Harris Reporting Date: 13/11/2012


The Old Dairy, Swanborough Farm

Swanborough, Lewes,

East Sussex, BN7 9PF

ANALYTICAL REPORT No. AR41394

Samples Received By:- Laboratory Courier

Samples Received:- 06/11/12

Your Job No: LW23258

Site Location: King Offa Nursery, Bexhill

No Samples Received:- 5

Report Checked By:- Authorised By:-

Steve Knight Mike Varley BSc, CChem, CSci, FRSC

Director Chief Chemist

Any comments, opinions, or interpretations expressed herein are outside the scope of UKAS accreditation (Accreditation Number 2683)

2683 2683

The Environmental Laboratory Ltd. Reg. No.3882193 . Page 1 of 3

2683 2683 Your Job No: LW23258

F.A.O. David Harris Reporting Date: 13/11/12


The Old Dairy, Swanborough Farm

Swanborough, Lewes,

East Sussex, BN7 9PF

SoilsCharacteristic Silty Clay loam Silty Clay loam Sandy Silt

loam

Clay Clay

TP/BH BH1 BH2 BH3 BH4 BH4

Depth (m) 1.50 2.20 2.00 1.50 3.00

Our ref 52534 52535 52536 52537 52538

pH Value** (Units) 7.6 4.8 4.9 6.7 7.0

Water Soluble Sulphate (mg/l as SO4) 11 25 <10 <10 <10

All results expressed on dry weight basis

** - MCERTS accredited test

SBB


Location: King Offa Nursery, Bexhill

Tel: 01424 718618 Fax: 01424 729911

ANALYTICAL REPORT No. AR41394

Unit A2, Windmill Road, Ponswood Industrial Estate, St Leonards On Sea, East Sussex, TN38 9BY

The Environmental Laboratory Ltd - Registered in England No 3882193 Page 2 of 3

Unit A2

Windmill Road

Ponswood Industrial Estate

St Leonards on Sea

East Sussex

TN38 9BY

Telephone (01424) 718618

Facsimile (01424) 729911


SAMPLE RECEIPT AND TEST DATES

Our Analytical Report Number AR41394

Your Job No: LW23258

Sample Receipt Date: 06/11/12

Reporting Date: 13/11/12

Registered: 06/11/12

Prepared: 07/11/12

Analysis complete: 13/11/12

TEST METHOD SUMMARY

PARAMETER Analysis Date Tested Method Technique

Undertaken on Number

pH Value** Air dried sample 09/11/12 113 Probe

Water Soluble Sulphate Air dried sample 09/11/12 209 Colorimetry

** - MCERTS Accredited test

Determinands not marked with * or ** are non accredited

MCERTS accreditation covers samples which are predominantly sand, clay, loam or combinations of these three soil types

2683 2683

Any comments, opinions, or interpretations expressed herein are outside the scope of UKAS accreditation (Accreditation Number 2683)

The Environmental Laboratory Ltd. Reg. No.3882193 . Page 3 of 3

Report No: LW23258

FIGURES Figure 1 Site Plan Figure 2 Exploratory Hole plan

Site Location Plan

Not To Scale

SITE: King Offa Nursery, Bexhill, East Sussex

N

Site Location

Figure 1

LW23258

© OpenStreetMap contributors, CC BY-SA

Borehole Location Plan

Not To Scale

SITE: King Offa Nursery, Bexhill, East Sussex Figure 2

LW23258

N

BH1

BH2

BH3

BH4

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