GEOTECHNICAL AND ENVIRONMENTAL ENGINEERS · GEOTECHNICAL AND CONTAMINATION STATUS ASSESSMENT REPORT...

SEAFORD HEAD SIXTH FORM

STEYNE ROAD

SEAFORD

EAST SUSSEX

GEOTECHNICAL AND

CONTAMINATION STATUS

ASSESSMENT REPORT

Report No. LW24146 July 2013

Report prepared for the benefit of:

Kier Construction

Longley House

International Drive

Southgate Avenue

Crawley

West Sussex

RH10 6AQ

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


STEYNE ROAD

SEAFORD

EAST SUSSEX

GEOTECHNICAL AND

CONTAMINATION STATUS

ASSESSMENT REPORT

Report No. LW24146 July 2013

FACTUAL REPORT Prepared By:

Rebecca Jones

BSc FGS

Approved By:

John Bewick

BSc MSc CEng CEnv MICE

GEOTECHNICAL ASSESSMENT Prepared By:

Rebecca Jones

BSc FGS

Approved By:

John Bewick


CONTAMINATION STATUS Prepared By:

Rebecca Jones

BSc FGS

Approved By:

John Bewick


Report No: LW24146/contents


STEYNE ROAD

SEAFORD

EAST SUSSEX

GEOTECHNICAL AND

CONTAMINATION (PHASE II)

ASSESSMENT REPORT

TABLE OF CONTENTS

Page i of ii

Page

1. INTRODUCTION 1

2. SITE DETAILS 2

2.1 Site Description 2

2.2 Expected Geology 2

2.3 Radon 3

2.4 Aquifer Status and Groundwater Source Protection Zones 3

2.5 Hydrology 4

3. GROUND INVESTIGATION 5

3.1 Introduction 5

3.2 Exploratory Holes 5

3.3 Sampling 5

3.4 In Situ Testing 5

3.5 Installations 6

3.6 Laboratory Testing 6

4. GROUND CONDITIONS 8

4.1 Stratigraphy 8

4.2 Stability 8

4.3 Groundwater Conditions 8

4.4 Existing Foundations 9

5. GEOTECHNICAL ASSESSMENT 10

5.1 Foundations 10

5.2 Groundwater 11

5.3 Stability of Excavations 11

5.4 Aggressivity to Concrete 11

5.5 Ground Floors 12

5.6 Drainage 12

6. CONTAMINATION STATUS SUMMARY 13

6.1 Historical Map and Environmental Data 13

6.2 Preliminary Contamination Test Results 14

6.3 Gas Monitoring Results 14

6.4 Recommendations 15

7. CONCLUSIONS 16

Report No: LW24146/contents


STEYNE ROAD

SEAFORD

EAST SUSSEX

GEOTECHNICAL AND

CONTAMINATION (PHASE II)

ASSESSMENT REPORT

TABLE OF CONTENTS

Page ii of ii

TABLES

Table 1. Expected Geological Strata 2

Table 2. Geotechnical Testing 7

Table 3. Chemical Testing 7

Table 4. Summary of Geo-Environmental Data and Historical Maps 13

FIGURES

Figure 1 Site Location Plan

Figure 2 Site Plan

Figure 3 Foundation Details

APPENDICES

APPENDIX A

Exploratory Hole Notes

In Situ Testing Notes

Exploratory Hole Records

Dynamic Probe Records

Summary of Borehole Falling Head Soakage Test Results

Summary of Gas Analyses and Water Depths

APPENDIX B

Geotechnical Laboratory Testing Notes

Laboratory Test Results

i) Geotechnical Testing

ii) Contamination Testing

Report No: LW24146

Seaford Head Sixth Form, Steyne Road, Page 1 of 17 Seaford, East Sussex

1. INTRODUCTION

The development proposals are understood to comprise the refurbishment of the Seaford Head Sixth Form buildings at Steyne Road, Seaford, East Sussex. Ashdown Site Investigation Limited was commissioned to carry out a combined geotechnical and contamination assessment of the site by Mr D Harwood of:

Kier Construction Longley House International Drive Southgate Avenue Crawley West Sussex RH10 6AQ

The instruction to proceed was received from the client, in an email dated 7

th June

2013. The purpose of the works was to:

i. assess shallow ground and groundwater conditions prevailing at the site; ii. undertake a brief review of EnviroCheck data provided by the client for the

site; iii. undertake preliminary contamination testing; iv. investigate the form of foundations to existing structures; and v. provide information to assist others in undertaking design of spread

foundations, ground floors and soakaways. The analysis and discussions contained in this report are based on the ground conditions encountered during the site work together with the findings from a programme of laboratory analyses. 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. Reference has been made in this report to EnviroCheck data pertaining to the site which was provided by the client (reference 45334891_1_1, dated April 2013). It is noted that the investigation was undertaken and the report was prepared specifically for the Client’s project and the recommendations given may not be appropriate to alternative schemes. 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: LW24146


2. SITE DETAILS

2.1 Site Description

The site comprises a rectangular shaped plot of land located at Steyne Road, Seaford, West Sussex, and is centred on the approximate Ordnance Survey national grid reference TV 4862 9881. A site location plan and site plan are presented as Figure 1 and Figure 2 respectively. The site lies to the north of Steyne Road and is bound to the west and north by residential houses and blocks of flats and to the east by a yard used for the storage and supply of timber. At the time of the intrusive works a one to two storey building occupied the majority of the southern part of the site. The existing main building was partly of a flint and mortar and partly of a brickwork and render construction. A mixture of brick and flint walls enclosed the northern part of the site. Several small outbuildings were present to the north east of the main building. Over the northern and central part of the site the topography was relatively level but the southernmost part sloped moderately downwards to the south with a small retaining wall present along the southern boundary between the site and the road.

2.2 Expected Geology

The stratigraphic succession expected to underlie the site is presented in the following table. In preparing the table reference has been made to the EnviroCheck information provided by the client, the British Geological Survey 1:50,000 series scale map and the British Geological Survey lexicon of named rock units. Table 1. Expected Geological Strata

Type Stratum Age

Superficial Deposits None Recorded N/A

Bedrock Geology Lambeth Group Eocene

Culver Chalk Formation Campanian

The geological map shows the northern part of the site is underlain by the Lambeth Group deposits and the southernmost part of the site may be expected to be underlain by the White chalk Subgroup (Culver Chalk Formation).

2.2.1 Lambeth Group

The Lambeth Group comprises a complex and laterally variable sequence of sedimentary deposits including clay, silt, sand and gravel. Inter-laminated clay

Report No: LW24146


and sand deposits are common in the lower part of the succession. The component formations are the Upnor Formation, Reading Formation and Woolwich Formation.

2.2.2 White Chalk Subgroup (Culver Chalk Formation)

The White Chalk Subgroup (Culver Chalk Formation) comprises a weak, white chalk locally with flint bands together with scattered nodular flints. It may be expected to have a deeply convoluted upper surface as a result of solution weathering. The presence of cavities in the chalk is very rare and solution features, if present, can be expected to be infilled with Quaternary deposits such as the Head. The infill material may be significantly weaker than the surrounding chalk. Solution features can comprise pipes extending to several metres deep into the chalk or conical depressions and basin shaped structures.

2.3 Radon

The Health Protection Agency (HPA) and its predecessor the National Radiological Protection Board (NRPB) have recommended to government that excessive exposures to radon should be reduced. The HPA advise that the Action Level for radon in homes should be 200 Bq/m3, averaged over a year. Radon affected areas are defined as those areas with 1% or more of homes above this action level. The information provided in the EnviroCheck report indicates the site is in an area where between 5% and 10% of houses are above the action level. Radon protective measures will be required in the construction of new buildings. The exact nature of the radon protective measures should be determined in discussion with the local authority.

2.4 Aquifer Status and Groundwater Source Protection Zones

The Environment Agency designates aquifers in accordance with the Water Framework Directive. These designations not only reflect the importance of aquifers in terms of groundwater as a resource (drinking water supply) but also their role in supporting surface water flows and wetland ecosystems. The aquifer designation data is based on geological mapping provided by the British Geological Survey. The Lambeth Group expected beneath the northern part of the site is classified as a Secondary A Aquifer. Secondary A Aquifers are characterised by permeable layers capable of supporting water supplies at a local rather than strategic scale, and in some cases forming an important source of base flow to rivers. The White Chalk Subgroup expected to outcrop beneath the southernmost part of the site is classified as a Principal Aquifer. Principal Aquifers comprise deposits that have high intergranular and/or fracture permeability, usually providing a high

Report No: LW24146


level of water storage. They may support water supply and/or river base flow on a strategic scale. The site does not lie within an Environment Agency Source Protection Zone with regard to the protection of the quality of groundwater that is abstracted for potable supply.

2.5 Hydrology

The nearest significant surface water feature is the English Channel located some 500m to the south west of the site. The EnviroCheck data indicates that an Environment Agency Zone 2 is present some 33m to the south of the site. A Zone 2 designation indicates that the site could be affected by an extreme flood event. The annual risk of these outlying flood zones being affected by a major flood from the sea is reported to be between 0.5% (1 in 200) and 1% (1 in 100). There are no flood defences, areas benefiting from flood defences or areas used for flood storage within 250m of the site.

Report No: LW24146


3. GROUND INVESTIGATION

3.1 Introduction

The ground investigation comprised the excavation of a series of boreholes and hand dug pits. The fieldwork was carried out on 18

th June and 1

st July 2013. The

exploratory hole locations are shown on the Site Plan (Figure 2). Descriptions of the strata encountered and comments on groundwater conditions are shown in the exploratory hole records given in Appendix A. Notes to assist in the interpretation of the records are also contained in the appendix.

3.2 Exploratory Holes

3.2.1 Dynamic Sampler Boreholes

Five boreholes (designated WS1 to WS5) were drilled to depths of between 2.0m and 3.0m below ground level. The boreholes were formed by a series of 1.0m long hollow steel sampler tubes, reducing in diameter from 100mm to 35mm, driven into the ground by means of a hand held hydraulic hammer. The sampler was extracted from the ground using either a hand operated or hydraulically operated jack and the enclosed samples recovered in 1.0m long plastic liners. The system enables sub-samples to be taken for detailed examination and laboratory testing.

3.2.2 Foundation Inspection Pits

Seven pits (designated TP1 to TP7) were excavated using hand-tools to depths of between 0.5m and 1.5m below ground level to enable inspection of the foundations to existing buildings.

3.3 Sampling

Disturbed samples of soil were taken at the depths shown in the exploratory hole records and were collected in either plastic bags, plastic tubs or amber jars fitted with gas tight lids. On collection amber jars were stored in cool boxes with cooling blocks to maintain temperatures below 4°C and were transferred to refrigerators upon return to the office until forwarded to the external accredited laboratory.

3.4 In Situ Testing

The depths of in situ testing, together with the test results, are given on the exploratory hole records or are summarised separately in Appendix A. Notes

Report No: LW24146


providing additional information on the tests that were performed are also included in Appendix A.

3.4.1 Perth Penetrometer Tests

Perth penetrometer tests were undertaken in the coarse grained soils encountered within the exploratory holes. Testing was carried out in accordance with Australian Standard AS 1289:6.3.3-1997, Method of Testing Soils for Engineering Purposes; no equivalent European or British Standard having been published to date.

3.4.2 Undrained Shear Strength

Undrained shear strength determinations were made within samples of the fine grained soils held in the sampler liners using a hand penetrometer. Although samples taken by the dynamic sampling technique cannot be regarded as being undisturbed for testing purposes, penetrometer testing can provide a useful indication of the strength of the material.

3.4.3 Soakage Testing

Falling head soakage testing was carried out in boreholes WS2 and WS3 at a depth of 2.0m below ground level within the Lambeth Group soils. Due to the restricted access on site and the need to use of hand held equipment, casing could not be installed within the boreholes and as such the soakage tests were non standard but were conducted to provide an indication of the soil infiltration rate.

3.5 Installations

Gas and groundwater monitoring standpipes were installed to depths of between 2.6m and 3.0m within boreholes WS1, WS4 and WS5. Descriptions of the installations are shown in the exploratory hole records given in Appendix A. The standpipes were monitored on three occasions between 25

th June and 12

th

July 2013. The readings are presented in Appendix A.

3.6 Laboratory Testing

Results from the laboratory tests are provided in Appendix B.

3.6.1 Geotechnical 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

Report No: LW24146


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 test results are discussed in Section 5. Table 2. Geotechnical Testing

Type of test No. of samples tested

Moisture Content 2

Particle Size Distribution 5

3.6.2 Chemical Testing

Chemical testing of selected samples was undertaken by a laboratory with recognised (UKAS and MCERTS) accreditation for quality control. The types and numbers of tests undertaken are detailed in the following table. The results of the testing are discussed in Sections 5 and 6. Table 3. Chemical Testing

Determinand No. of soil samples tested

Arsenic 5

Cadmium 5

Chromium 5

Lead 5

Mercury 5

Nickel 5

Copper 5

Zinc 5

Selenium 5

Hexavalent Chromium 5

Water Soluble Boron 5

pH 8

Organic Matter 5

Speciated PAH 5

Speciated Petroleum Hydrocarbons (Equivalent Carbon Weight

Fractions) 5

Asbestos 5

Water Soluble Sulphate 3

Report No: LW24146


4. GROUND CONDITIONS

4.1 Stratigraphy

4.1.1 Surface Covering

The exploratory boreholes were excavated through a surface cover of weak asphalt some 50mm to 100mm in thickness. A similar thickness of concrete was present at the locations of trial pits TP1, TP2 and TP7. No specific surfacing materials were noted in trial pits TP4, TP5 or TP6.

4.1.2 Made Ground

Made ground, generally comprising silty clayey sand and gravel comprising in a variable quantities of flint, concrete, brick, chalk, clay pipe fragments and clinker was recorded at each exploratory hole position, extending to depths of between 0.5m and 1.3m below ground level.

4.1.3 Lambeth Group

Underlying the made ground, the investigation progressed into undisturbed loose becoming medium dense sand containing subordinate horizons of flint gravel and clay. These deposits were recorded to the full depth of the hand dug trial pits and boreholes WS1, WS2, WS3 and WS5 and to a depth of 2.85m in WS4. These soils are considered to represent the Lambeth Group deposits indicated on the published geological map.

4.1.4 White Chalk Subgroup

The White Chalk Subgroup deposits were proved in borehole WS4 only where they were present below the depth of 2.85m to the base of the borehole at 3m below ground level.

4.2 Stability

Instability was recorded locally within the made ground and coarse grained undisturbed soils.

4.3 Groundwater Conditions

Each of the exploratory holes was recorded as being dry during the course of the investigation and also during subsequent monitoring visits.

Report No: LW24146


4.4 Existing Foundations

Details of the foundations encountered within the foundation inspection pits are included as Figure 3 of this report. Trial pits TP1, TP2 and TP3 excavated within the internal courtyard, indicate the foundations of the existing building comprise mass concrete spread foundations bearing at depths of 1.30m and 1.48m below ground level at the position investigated. The foundations of the boundary walls appeared to comprise mass concrete spread foundations bearing at a depth of between 0.50m and 0.62m below ground level. The concrete slab exposed in trial pit TP4 was recorded to be some 370mm thick. All of the foundations appear to be supported within the Lambeth Group soils.

Report No: LW24146


5. GEOTECHNICAL ASSESSMENT

It is understood that the development proposals for the site comprise the refurbishment of the existing school buildings, including the demolition of the outbuildings and caretakers house. At the time of writing, no details were available on either the location or loads likely to be applied to new foundations.

5.1 Foundations

5.1.1 Soil Shrinkage/Heave Potential

The undisturbed sand and gravel soils of the Lambeth Group and the chalk of the White Chalk Subgroup may be considered to be non-plastic and hence non-shrinkable. It is noted that the soils encountered beneath the site predominantly comprised sand and gravel and that only a locally limited thickness of clay was recorded in borehole WS4. It is therefore considered that no specific precautions are required with respect to protecting foundations founded through or within these soils from the effects of soil heave/ shrinkage.

5.1.2 Spread Foundations

Any made ground and any soils disturbed by the construction or removal of any previously existing foundations or services should be regarded as being potentially variable in nature and state of compaction and, as such, unsuitable as a founding medium for shallow footings. New footings should be constructed so as to bear below such soils and onto undisturbed, competent, natural deposits. As noted earlier in the report, very loose and becoming medium dense sands and gravels of the Lambeth Group were recorded beneath the made ground. It is considered that a net allowable bearing capacity of 50kN/m

2 may be assumed

for the design of spread (pad or strip) foundations up to 1.0m across bearing within the very loose sands of the Lambeth Group that were present to depths of around 1.5m below ground level. An increased bearing capacity of 100kN/m

2 may

be assumed for similar sized footings bearing within the medium dense sands typically encountered below depths of 1.5m. The quoted bearing capacities are expected to limit settlement to less than 25mm. Care must be taken to ensure that new foundations do not undermine or impose additional loading (vertical or lateral) on existing foundations. Similarly, the construction of new foundations must be carefully undertaken and monitored in those situations where temporary works may affect existing foundations.

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It is recommended that, where a bearing capacity in excess of 50kN/m² is to be utilised, the soils at the proposed founding depth should be inspected by suitably qualified persons to confirm the relative density of the founding medium.

5.2 Groundwater

Groundwater was not encountered during the period of either the intrusive works or the subsequent monitoring visits. It is possible however that during periods of heavy rainfall perched or surface water run-off may enter excavations. In such circumstances it would be expected that water could be adequately managed by pumping from sumps or by natural drainage.

5.3 Stability of Excavations

All unsupported excavations within both the made ground and Lambeth Group soils should be assumed to be subject to short term instability and should be suitably supported or side slopes battered back to a safe angle of repose. Where personnel access is required into any excavation, its stability must be assessed by a suitably qualified, experienced and responsible person. In any case it is recommended that where personnel access into excavations greater than 1.2m depth is necessary, excavations should be fully supported or side slopes battered back to a safe angle of repose. Particular attention must be paid to ensuring the stability of nearby structures and neighbouring sites.

5.4 Aggressivity to Concrete

In view of the soils encountered beneath the site it is considered that ‘natural ground conditions’ may be assumed for the purpose of assessing the aggressivity of the chemical environment for concrete classification (ACEC class). Given that groundwater was not encountered, ‘static groundwater’ conditions may also be assumed. Chemical analysis of the soil indicates a sulphate content falling into Design Sulfate Class DS-1 of Table C1 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 alkaline. In accordance with the BRE digest, a DS-1 Design Sulfate Class and an AC-1 ACEC classification may be assumed as a minimum for the design of concrete in contact with the ground.

Report No: LW24146


5.5 Ground Floors

In view of the variable and locally significant thickness of made ground underlying the site, together with very loose granular soils, it is recommended that ground floors for all sensitive structures should be suspended. The detailing of services through, or under, ground-bearing floors should incorporate flexible connections and, where appropriate, enhanced falls.

5.6 Drainage

Non-standard falling head soakage tests were made in the uncased boreholes WS2 and WS3. From the results of the tests, calculations were made to estimate the infiltration rate that could be expected for soakaways constructed to discharge into the soils within the test zone. The soil infiltration rate was calculated by dividing the volume of water lost during the test by the product of the average surface area of the trial in contact with water during the test period and the test duration in seconds. The following infiltration rates were derived:

WS2 Test 1 f = 4.7 x 10-6 m/s

WS2 Test 2 f = 3.3 x 10-6 m/s

WS3 Test 1 f = 1.3 x 10-6 m/s

The value ‘f’ is equivalent to the soil infiltration coefficient ‘q’ quoted in the Construction Industry Research and Information Association (CIRIA) Report 156. Although the rate of infiltration was relatively low it is possible that the Lambeth Group soils may be capable of accepting surface water run-off via soakaways. The design of soakaways should be carefully considered to ensure they are capable of half emptying within a 24hour period as is required by the BRE 365 Guide. Alternatively deep soakaways constructed into the White Chalk Subgroup deposits could be considered, although further testing with the aid of deep boreholes would be required to provide information for design purposes . To minimise the risk of subsidence, soakaways should be constructed a minimum of 5.0m away from proposed or existing buildings. In the event that discharge to ground via soakaways is proposed, it is recommended that designers refer to Pollution Prevention Guidance Notes (PPGs) published by the Environment Agency for advice on legal requirements and good practice to reduce risks to groundwater. In particular reference should be made to PPGs 1 and 3, providing general advice on the prevention of pollution and the use and design of oil separators in surface water drainage systems, respectively. The Local Authority and/or relevant water company should be consulted in relation to consent for discharge of water from rooftops, areas of hardstanding and roadways to drains.

Report No: LW24146


6. CONTAMINATION STATUS SUMMARY

A detailed ground contamination risk assessment of the site was beyond the scope of this investigation. However, the Envirocheck information pertaining to the site provided by the client was reviewed and the results of laboratory testing for common contaminants have been compared with generic soil screening values to provide an indication of the current contamination status of the site.

6.1 Historical Map and Environmental Data

Historical Ordnance Survey maps and geo-environmental data sets covering the area of the site have been reviewed. It is noted that each historical map presents information applicable at the time of the survey (or revision date) and is subject to surveying and cartographic errors and/or advances. Revisions to maps are made at irregular intervals and it is possible that significant developments may have taken place on or within the vicinity of the site that have not been revealed by the historical maps. Significant details depicted on the maps and geo-environmental data sets are identified in the following table. Table 4. Summary of Geo-Environmental Data and Historical Maps

Section ASI Summary and Assessment

Historical Maps

At the time of the earliest map, dated 1874, a building occupied the southern part of the site with a smaller structrue in the central part of the site. By the time of the 1910 map the southern building had been extended, possibly incorporating the smaller structure in the centre of the site. Other small structures are shown along the eastern site boundary. Significant residential development had taken place around the site by 1963. On the 1974 map another building is shown occupying the northern part of the site and the smaller structures have been enlarged. Immediately to the east a Timber Yard is shown and a garage is also indicated some 50m to the east. Between 1974 and 1993 the site and surrounding area do not appear to have changed significantly. Current mapping/data shows the main building in the southern part of the site with smaller structures along the eastern boundary but the building located in the northern part of the site is no longer present. In view of the latter there is the potential for metal, PAH and asbestos contaminated made ground to be present from the demolition of structures on site.

Environmental Data

No significant entries are identified regarding Environmental Permits/Discharge Consents, Pollution Incidents or Registers. A historic local authority registered landfill is indicated some 210m to the west of the site which potentially may pose a significant ground gas risk to the site. No significant risks from mining, extractions or cavities are identified. An obsolete fuel station is marked 231m to the west of the site. The nearest trade entry is Marden Motors garage services located 49m to the east of the site. The remaining trade entries are not considered to pose a significant risk to the site due to their distances from site.

Report No: LW24146


Marden Motors located some 49m to the east possibly represents a potential hydrocarbon contamination risk to the site. However given that the garage is located down gradient of the site it is unlikely to pose a significant risk to the proposed development. Similarly the presence of a fuel station some 231m is considered unlikely to pose a significant risk to the proposed development due to its distance from site.

6.2 Preliminary Contamination Test Results

Five samples of made ground were tested for a range of commonly occurring metals and polycyclic aromatic hydrocarbons (PAH) compounds. Selected samples were also screened for petroleum hydrocarbons and asbestos contamination. It is understood that the development proposals for the site comprise the refurbishment of the existing school building and therefore the test results have been compared to soil screening values calculated for a primary school site. With the exception of the sample tested from TP1 at a depth of 0.5m none of the samples recorded significantly elevated concentrations of metal contaminants within the made ground soils. The sample from TP1, located within the central courtyard area, recorded a concentration of lead of 1992mg/kg which is above the soil screening value for a school site. The samples tested for PAH compounds did not record concentrations above the soil screening values for a school site. However should the proposed end use of the development change it should be noted that the sample tested from borehole WS3 at 0.5m did record elevated levels of PAH that would be marginally above the soil screening values for a residential site. None of the made ground samples tested recorded petroleum hydrocarbons above the detection limit of the test. No suspected asbestos containing materials were noted within the soils encountered within the exploratory hole and the five samples screened did not record the presence of asbestos fibres within the made ground soils.

6.3 Gas Monitoring Results

Monitoring of the gas concentrations within the standpipes in boreholes WS1, WS4 and WS5 was carried out on three occasions. Peak levels of carbon dioxide of up to 1.8% and carbon monoxide of up to 12ppm were recorded. No detectable methane, gas pressure or gas flow was recorded from any of the boreholes. Based on the results of the gas monitoring carried out to date no specific gas precaution measures appear to be required within the development.

Report No: LW24146


6.4 Recommendations

In the event that areas of soft landscaping are to be included in the proposed redevelopment then some remedial works may be required by regulators or warrantors due to the elevated concentrations of lead recorded with the made ground deposits beneath the courtyard area. Such remedial measures would be likely to comprise provision of a suitable thickness of clean cover soils in areas of proposed soft landscaping that were underlain by made ground deposits. Alternatively the made ground could be removed entirely from the site and be replaced by an equivalent depth of suitable material. Further sampling, testing and analysis would be appropriate once areas of soft landscaping (if any) have been determined. In the event that no soft landscaping was to be incorporated into the development and all areas were to be hard surfaced then no remediation measures appear to be required in connection with the protection of end users. Precautions may however be need to protect services.

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7. 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 underlying soils to comprise a variable thickness of made ground, overlying largely granular soils of the Lambeth Group. Borehole WS4 only progressed into the White Chalk Subgroup deposits underlying the Lambeth Group soils at a depth of 2.85m below ground level.

Groundwater was not encountered either during the period of the intrusive works or subsequent monitoring visits.

In general the soils beneath the site predominantly comprised sand and gravel. No specific precautions are therefore considered to be required with respect to protecting foundations from the effects of soil heave/ shrinkage.

A net allowable bearing capacity of 50kN/m2 may be assumed for the design

of spread (pad or strip) foundations up to 1.0m across bearing within the loose sands of the Lambeth Group. An increased bearing capacity of 100kN/m

2 may be assumed for the design similar sized footings bearing

within the medium dense sands typically encountered below depths of 1.5m.

Ingress of perched water or surface run off into excavations should be adequately managed by pumping from sumps or natural drainage.

All unsupported excavations within made ground and Lambeth Group soils should be assumed to be subject to short term instability and should be suitably supported or side slopes battered back to a safe angle of repose.

A DS-1 Design Sulfate Class and an AC-1 ACEC classification may be assumed as a minimum for the design of concrete in contact with the ground.

In view of the variable and locally significant thickness of made ground underlying the site, it is recommended that ground floors should be suspended.

It is possible that the Lambeth Group soils may be capable of accepting surface water run-off via soakaways, though the design of soakaway geometries should be carefully considered to ensure they are capable of half emptying within a 24hour period, as required by BRE 365.

Report No: LW24146


If the development proposals include areas of soft landscaping then some remedial works may be required due to the elevated concentrations of lead recorded with the made ground deposits encountered beneath the courtyard area.

Ashdown Site Investigation Limited

July 2013

Report No: LW24146

FIGURES Figure 1 Site Location Plan Figure 2 Site Plan Figure 3 Foundation Details

Site Location Plan

Not To Scale

SITE: Seaford Head Sixth Form, Steyne Road, Seaford,

East Sussex

N

Site Location

Figure 1

LW24146

© OpenStreetMap contributors, CC BY-SA

GP

RS

c an

240

GPR Scan 200

GP

RS

can

921

Courtyard

WS1TP4

TP6

TP5

TP7

WS2

WS5

WS3

WS4

TP1

TP2

& TP3

Approx location

of sheds

Site Plan

DRAWING TITLE:

2LW24146

1:250July 2013TSH

Seaford Head Sixth FormSteyne RoadSeaford

East Sussex

FIGURE NO.:

DATE:DRAWN BY:

REPORT REF.:

SITE:

ASHDOWN SITEINVESTIGATION

LIMITED

The Old Dairy,Swanborough Farm,

Swanborough,Lewes,

East SussexBN7 3PF

Tel: 01273 483119 Fax: 01273 483104

email: [email protected]

SCALE (at A3):

TP4

MADE GROUND

Possibly natural

below 0.4m depth

Concrete slab

MADE GROUND

SAND

SAND

MADE GROUND

Concrete Concrete

Brickwork

Concrete

SAND

Top of wall

Brickwork and flint wall

Flint wall

TP5 TP6

Top of wall

SAND

Concrete

Concrete over

MADE GROUND

Brickwork

TP7

Brickwork

Weak concrete

SAND

Weak concrete Weak concrete

SAND

Weak concrete

Brickwork

MADE GROUND

DPC

Brickwork

Concrete

Shed

Concrete

Brickwork

Courtyard

Flin

twall

Edge of pit

B'

A A'

DPC

N

Flint wall

Window sill

Window

TP1

B Brickwork wall

TP2 & TP3 - Plan

Concrete

MADE GROUND Brickwork

DPC

Brickwork

Concrete

MADE GROUND

TP3 - A-A' TP2 - B-B'

SCALE (at A3):

Foundation DetailsDRAWING TITLE:

LW24146

TSH

DRAWN BY:

REPORT REF.:

SITE:

Seaford Head Sixth Form

Steyne RoadSeafordEast Sussex

FIGURE NO.:

3

July 2013

DATE:

1:20

The Old Dairy,Swanborough Farm,

Swanborough,Lewes,

East SussexBN7 3PF

Tel: 01273 483119 Fax: 01273 483104email: [email protected]

Report No: LW24146

APPENDIX A Exploratory Hole Notes In Situ Testing Notes Exploratory Hole Records Dynamic Probe Records Summary of Borehole Falling Head Soakage Test Results Summary of Gas Analyses and Water Depths

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. Thenumber of blows to drive in the sampling tube is shown after the test index letter in the SPTcolumn.

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 SampleE 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 startof the normal 450mm penetration, the number of blows to achieve the standard penetration of300mm (the ‘N’ value) is shown after the test index letter, but the seating blows through theinitial 150mm penetration are not reported unless the full penetration of 450mm cannot beachieved. In the latter case, the symbols below are added to the test index letter:-

S(R) Refusal of standard penetration test. Blow count reported includes seating blows. Totalpenetration of refused SPT reported in mm in brackets on borehole record.

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 seatingcount). The depths of both the top and bottom of the test drive are shown in the sample columnon the Borehole Record. If a sample is not recovered in the sampler, a disturbed sample istaken over the depth of the test as boring continues.

C Standard Penetration Test (SPT) conducted usually in coarse grained soils or weak rocks usingthe same procedure as for the SPT but with a 50mm diameter, 60º apex solid cone fitted inplace of the sampler. Variations in test results are indicated by the same symbols as for theSPT (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. Numberof blows for 300mm penetration shown under Vane/Pen Test and N Value column. In sand thenumber 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 StandardGeotechnical investigation and testing – Identification and classification of soil, Part 1 Identification anddescription (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 samplesand the strength is based on results of in situ and/or laboratory undrained shear strength tests whencarried out.

The consistency is determined on the following basis:

Consistency Manual Test

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

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

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

be indented by thumbnailBased 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 kPaLow 20-40 kPaMedium 40-75 kPaHigh 75-150 kPaVery High 150-300 kPaExtremely 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 fieldusing 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 coarsegrained material within the soil mass. To reflect this, it is the soil type that dominates the behaviour ofthe 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 fieldestimations and the results of the Standard Penetration Test (SPT) and equivalent correlation fromother testing. The classification in terms of "N" Values is as follows:

SPT ‘N’ Value Relative Density

0-4 Very Loose4-10 Loose10-30 Medium Dense30-50 DenseGreater than 50 Very Dense

3 Rock Description

Description and classification of rocks has been carried out using as a general basis the BritishStandard Geotechnical investigation and testing – Identification and classification of rock, Part 1Identification 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 UnconfinedCompressiveStrength (MPa)

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

hammer, peeled by pocket knife1 to 5

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

5 to 25

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

25 to 50

Strong Requires more than one blow of geological hammer tofracture

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 ThicknessVery Thick >2000mm

Discontinuity SpacingVery Wide >2000mm

Thick 2000-600mmMedium 600-200mmThin 200-60mmVery Thin 60-20mmThickly Laminated 20-6mmThinly Laminated <6mm

Wide 2000-600mmMedium 600-200mmClose 200-60mmVery Close 60-20mmExtremely Close <20mm

Chalk

Chalk description is based on BS EN ISO 14688 and BS EN ISO 14689. The classification of chalkgenerally follows the guidance offered by the Construction Industry Research and InformationAssociation (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 chalkclassification notes.

of 1

IN-SITU TESTING NOTES

1 Standard Penetration Testing Standard penetration testing (SPT) is carried out within a cased cable percussion borehole. The test is performed using a either a split spoon (barrel) sampler in finer grained deposits, or, in coarser grained soils or weak rocks, using a 50mm diameter, 60º apex solid cone fitted in place of the sampler. The sampler is driven into the deposits at the base of the borehole by means of a 63.5kg hammer falling freely through 760mm. 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. (BS EN ISO 22476-3:2005, Geotechnical investigation and testing – Field Testing, Part 3)

2 Dynamic Probe Testing The DPH (heavy) dynamic probing rig drives a 32mm diameter rod with a 15cm2 area, 90º end cone into the ground by means of a 50kg hammer which falls freely through a distance of 0.5m. The number of blows per 100mm penetration (N100) is recorded.

The DPSH (super heavy) dynamic probing rig drives a 35mm diameter rod with a 20cm2 area, 90º end cone into the ground by means of a 63.5kg hammer that falls freely through a distance of 0.75m. The number of blows per 100mm penetration (N100) is recorded. The results can provide a useful indication of the relative strength of the material. The dynamic probing is carried out in accordance with BS EN ISO 22476-2:2005.

A tentative correlation with the Standard Penetration Test (SPT) N value can be made summing three consecutive the N100 blow counts.

3 Perth Penetrometer Test

In this test a hardened stainless steel rod is driven into the deposit by a 9.5kg sliding hammer falling freely through 600mm. After an initial penetration of 150mm the number of blows required to drive the rod a further 300mm is recorded. In sand the Perth blow count gives a close correlation to the "N-value" that could be expected from a standard penetration test (SPT) made in similar materials. The results are less reliable in coarser grained materials but can give an indication of their engineering properties. The perth penetrometer test is carried out in accordance with the Australian Standard AS 1289:6.3.3-1997, Method of Testing Soils for Engineering Purposes, there is no European equivalent code.

4 Undrained Shear Strength

Undrained shear strength determinations are made in situ within the fine grained soils using a Geonor hand shear vane or (usually in the case of window sampler boreholes) a hand penetrometer. The test records the undrained shear strength (cohesion) in kN/m2. The shear vane records a maximum shear strength of 130kN/m2 and the hand penetrometer records a maximum shear strength of 250kN/m2.

3 California Bearing Ratio Test In this test a hand held Farnell cone penetrometer apparatus is pushed into the deposits for the estimation of the California bearing ratio of the subgrade (for use in pavement design). The test equipment is design for the estimation of the bearing ratio of fine grained soils (clay and silt) only and is unsuitable for use in coarse grained soils and rock.

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 Sample

Type From(m)

To(m)

Vane/ PenTest

N ValueLegend

Depth /Reduced

LevelStrata Descriptions

Remarks:

Depths

WS1

Seaford Head Sixth Form, Steyne Road, Seaford

LW24146

18/06/2013 18/06/2013

J T

J T

J T

P

J

D

P

D

D

0.20

0.50

0.90

1.00

1.30

1.35

1.45

2.00

3.00

1.45

1.75

4

23

0.00

0.10

1.20

2.50

3.00

Ground Level

Weak asphalt (50mm ) over,Fine to coarse gravel of chalk and brick.

MADE GROUND: Brown slightly clayey slightly gravelly silty fine tomedium sand. Gravel is fine to coarse flint with occasional chalk, clinkerand brick.

Loose brown and yellow brown fine to medium SAND. (Lambeth Group)becoming yellow brown below 1.3m depth.becoming medium dense below 1.5m depth.

Orange brown slightly clayey very sandy fine to coarse GRAVEL of flint/chert. (Lambeth Group)

End of Borehole

Hand Dynamic Sampler

Various

LG

Borehole dry and stable on completion.

Standpipe installed to 3.0m depth; 3.0m to 1.0m slotted pipe with gravel surround;1.0m to ground level plain pipe with bentonite seal; completed with gas tap andsecurity cover concreted flush with ground surface.

Borehole No.:

Site Name:

Job No.:


Excavation Method:

Borehole Diameter:

Made By:





Type From(m)

To(m)

Vane/ PenTest

N ValueLegend

Depth /Reduced


Remarks:

Depths

WS2


LW24146

18/06/2013 18/06/2013

J T

J T

D

J

J T

P

D

P

D

0.20

0.50

0.60

0.70

0.90

1.00

1.10

1.45

2.00

1.45

1.75

4

15

0.00

0.15

0.80

2.00

Ground Level

Asphalt (60mm) over,Gravel of chalk.


Loose orange brown fine to medium SAND. (Lambeth Group)

becoming yellow brown below 1.0m depth.

becoming medium dense below 1.5m depth.

End of Borehole


Various

LG


Borehole No.:

Site Name:

Job No.:


Excavation Method:

Borehole Diameter:

Made By:





Type From(m)

To(m)

Vane/ PenTest

N ValueLegend

Depth /Reduced


Remarks:

Depths

WS3


LW24146

18/06/2013 18/06/2013

J T

J T

J T

P

D

P*

D

0.20

0.50

1.00

1.00

1.10

1.45

2.00

1.45

1.60

8

9

0.00

0.10

0.30

0.90

2.00

Ground Level

Asphalt.

MADE GROUND: Gravel of concrete and brick hardcore with some fineto coarse gravel of tar bound stone.

MADE GROUND: Brown silty gravelly fine to medium sand. Gravel isfine to coarse concrete, brick and flint.

Loose to medium dense brown and yellow brown fine to medium SAND.(Lambeth Group)becoming yellow brown below 1.0m depth.


End of Borehole


Various

LG

Borehole dry on completion.

Borehole noted as very unstable on completion.

P* - blow count for 150mm penetration only.

Borehole No.:

Site Name:

Job No.:


Excavation Method:

Borehole Diameter:

Made By:





Type From(m)

To(m)

Vane/ PenTest

N ValueLegend

Depth /Reduced


Remarks:

Depths

WS4


LW24146

18/06/2013 18/06/2013

J T

D

J T

J T

D

P

P*

D

D H

D

0.15

0.50

0.55

0.95

1.00

1.00

1.45

2.00

2.70

3.00

1.45

1.60

11

8

60

0.00

0.80

0.90

1.95

2.60

2.85

3.00

Ground Level

Weak asphalt (70mm) over,MADE GROUND: Brown slightly clayey gravelly fine to medium sand.Gravel is fine to coarse concrete, brick and clay pipe with occasionalclinker.

MADE GROUND: Fine to coarse gravel of concrete and brick(?).

Medium dense brown and yellow brown fine to medium SAND.(Lambeth Group)

becoming orange brown below 1.8m depth.

Orange brown slightly clayey very sandy fine to coarse GRAVEL of flint/chert. (Lambeth Group)

Firm orange brown slightly gravelly silty sandy CLAY. Gravel is fine tomedium flint and ironstone. (Lambeth Group)

Off white and light orange brown CHALK recovered as silty gravel. Withoccasional flints. (White Chalk Subgroup, Grade Dc or better)

End of Borehole


Various

LG

Borehole dry on completion.

Borehole unstable in made ground.



Borehole No.:

Site Name:

Job No.:


Excavation Method:

Borehole Diameter:

Made By:





Type From(m)

To(m)

Vane/ PenTest

N ValueLegend

Depth /Reduced


Remarks:

Depths

WS5


LW24146

18/06/2013 18/06/2013

J T

J T

D

J T

D

P

P*

D

D

0.20

0.40

0.50

0.85

1.00

1.00

1.45

2.00

2.60

0.60

1.45

1.60

5

9

0.00

0.10

0.75

2.60

Ground Level

Weak asphalt.

MADE GROUND: Brown silty gravelly fine to medium sand. Gravel isfine to coarse flint and chalk with occasional clinker, brick and shellfragments.

becoming slightly gravelly below 0.5m depth.

Loose brown and yellow brown fine to medium SAND. (Lambeth Group)

becoming yellow brown below 1.0m depth.


End of Borehole

with coarse gravel of flint and chert at base.


Various

LG




Trial Pit No.:

Site Name:

Job No.:


Excavation Method:

Dimensions:

Made By:




Sample TypeFrom(m)

To(m)

Vane/ Pen TestN Value

LegendDepth /

ReducedLevel

Strata Descriptions

Remarks:

Depths

TP1


LW24146

01/07/2013 01/07/2013

J T

J T

J T

J T

D

P

P*

0.30

0.70

1.00

1.30

1.40

1.50

1.95

1.95

2.10

4

5

0.00

1.20

1.50

Ground Level

Concrete (50mm) over,MADE GROUND: Dark brown/ black clayey gravelly sand. Gravel is fineto medium flint, brick and concrete.

Loose yellow brown/ green fine to medium SAND. (Lambeth Group)

End of Pit

Hand Dug

IT

Trial pit dry and stable on completion.


Trial Pit No.:

Site Name:

Job No.:


Excavation Method:

Dimensions:

Made By:




Sample TypeFrom(m)

To(m)


LegendDepth /

ReducedLevel

Strata Descriptions

Remarks:

Depths

TP2 & TP3


LW24146

01/07/2013 01/07/2013

J T

J T

J T

J T

D

P

P*

0.80

0.50

0.80

1.30

1.40

1.50

1.95

1.95

2.10

5

3

0.00

0.10

0.92

1.30

1.50

Ground Level

Concrete.

MADE GROUND: Dark brown/ black slightly clayey gravelly fine sand.Gravel is fine to medium flint, brick, concrete and china fragments.

Weak concrete.

Loose yellow brown fine to medium SAND. (Lambeth Group)

End of Pit

Hand Dug

IT



Trial Pit No.:

Site Name:

Job No.:


Excavation Method:

Dimensions:

Made By:




Sample TypeFrom(m)

To(m)


LegendDepth /

ReducedLevel

Strata Descriptions

Remarks:

Depths

TP4


LW24146

18/06/2013 18/06/2013

D 0.50

0.00

0.50

Ground Level

MADE GROUND: Brown slightly clayey slightly gravelly silty fine tomedium sand. Gravel is fine to coarse flint with occasional chalk, clinkerand brick.becoming orange brown mottled and slightly gravelly (possibly reworkednatural) below 0.4m depth.

End of Pit

Hand Dug

LG


Trial Pit No.:

Site Name:

Job No.:


Excavation Method:

Dimensions:

Made By:




Sample TypeFrom(m)

To(m)


LegendDepth /

ReducedLevel

Strata Descriptions

Remarks:

Depths

TP5


LW24146

18/06/2013 18/06/2013

J T

D

P

P

0.20

0.60

0.70

1.15

1.15

1.45

4

6

0.00

0.50

0.70

Ground Level


Loose brown and yellow brown fine to medium SAND. (PossiblyReworked/ Lambeth Group)

End of Pit

Hand Dug

LG


Trial Pit No.:

Site Name:

Job No.:


Excavation Method:

Dimensions:

Made By:




Sample TypeFrom(m)

To(m)


LegendDepth /

ReducedLevel

Strata Descriptions

Remarks:

Depths

TP6


LW24146

18/06/2013 18/06/2013

J T

D

P

P

0.30

0.60

0.80

1.25

1.25

1.55

6

17

0.00

0.50

0.80

Ground Level


Loose to medium dense yellow brown fine to medium SAND. (LambethGroup)

End of Pit

Hand Dug

LG


Trial Pit No.:

Site Name:

Job No.:


Excavation Method:

Dimensions:

Made By:




Sample TypeFrom(m)

To(m)


LegendDepth /

ReducedLevel

Strata Descriptions

Remarks:

Depths

TP7


LW24146

18/06/2013 18/06/2013

J T

D

P

P

0.30

0.70

0.70

1.15

1.15

1.45

3

4

0.00

0.60

0.70

Ground Level

Concrete over,MADE GROUND: Brown slightly clayey slightly gravelly silty fine tomedium sand. Gravel is fine to coarse flint with occasional chalk, clinkerand brick.

Loose brown and yellow brown fine to medium SAND. (Lambeth Group)

End of Pit

Hand Dug

LG


ASHDOWN SITE INVESTIGATION LIMITED

Site: Seaford Head Sixth Form, Steyne Road, Seaford, East Sussex.

Report No.: Sheet No.:

LW24146 1 of 1

SUMMARY OF BOREHOLE FALLING HEAD SOAKAGE TEST RESULTS

Borehole WS2 – Test 1

Borehole WS2 – Test 2

Borehole WS3

Time (mins) Depth to Water (m

bgl)

Time (mins)

Depth to Water (m

bgl)

Time (mins)

Depth to Water (m

bgl) 0 0.2 0 0.15 0 0.58

1 0.5 1 0.40 1 0.61

2 0.61 2 0.48 2 0.62

3 0.68 3 0.52 4 0.64

4 0.72 4 0.54 8 0.70

5 0.77 10 0.66 16 0.74

8 0.82 18 0.78 32 0.79

20 1.11 80 1.32 60 0.88

37 1.32

53 1.45

69 1.50 Borehole Depth (m bgl)

2.00 Borehole

Depth (m bgl)

2.00 Borehole

Depth (m bgl)

3.00

Depth Borehole Diameter

(mm)

Depth

Borehole Diameter

(mm)

Depth

Borehole Diameter

(mm) GL to 1.00m

80.00 GL to 1.00m

80.00 GL to

1.00m 80.00

1.00m to 2.00m

60.00 1.00m to 2.00m

60.00 1.00m to

2.00m 80.00

Remarks: bgl - below ground level.

ASHDOWN SITE INVESTIGATION LIMITED

Site: Seaford Head Sixth Form, Steyne Road, Seaford, East Sussex Report No.:

Sheet No.: LW24146

1 of 1

SUMMARY OF GAS ANALYSES AND WATER DEPTHS

WS1

Date Methane (%)

Carbon Dioxide (%)

Oxygen (%)

Carbon monoxide

(ppm)

Hydrogen Sulphide

(ppm)

Gas Pressure

(mb)

Emission Rate

(l/hr)

Standing Water Depth (m bgl)

Atmospheric Pressure (mb)

Peak

Static

Peak

Static

Min.

Static

On-site

Trend

25/06/13 0.0 0.0 0.9 0.9 19.5 19.5 9 0 0.0 0.0 Dry 1031 Rising

01/07/13 0.0 0.0 1.4 1.4 19.0 19.0 8 0 0.0 0.0 Dry 1019 Falling

12/07/13 0.0 0.0 1.8 1.8 18.7 18.9 9 0 0.0 0.0 Dry 1026 Rising

WS4

Date Methane (%)

Carbon Dioxide (%)

Oxygen (%)

Carbon monoxide

(ppm)

Hydrogen Sulphide

(ppm)

Gas Pressure

(mb)

Emission Rate

(l/hr)



Peak

Static

Peak

Static

Min.

Static

On-site

Trend

25/06/13 0.0 0.0 0.4 0.2 20.5 20.5 9 0 0.0 0.0 Dry 1031 Rising

01/07/13 0.0 0.0 0.5 0.5 20.1 20.1 10 0 0.0 0.0 Dry 1019 Falling

12/07/13 0.0 0.0 0.6 0.6 20.0 20.0 8 0 0.0 0.0 Dry 1026 Rising

WS5

Date Methane (%)

Carbon Dioxide (%)

Oxygen (%)

Carbon monoxide

(ppm)

Hydrogen Sulphide

(ppm)

Gas Pressure

(mb)

Emission Rate

(l/hr)



Peak

Static

Peak

Static

Min.

Static

On-site

Trend

25/06/13 0.0 0.0 1.3 1.3 18.9 18.9 8 0 0.0 0.0 Dry 1031 Rising

01/07/13 0.0 0.0 1.5 1.5 18.5 18.5 12 0 0.0 0.0 Dry 1019 Falling

12/07/13 0.0 0.0 1.8 1.8 18.4 18.4 8 0 0.0 0.0 Dry 1026 Rising Remarks: Readings taken using an infra red gas analyser. Emission rate measured using a flow pod attached to infra red gas analyser. * Groundwater monitoring standpipe only.

Weather Conditions: 25/06/13 – Sunny 01/07/13 – Sunny & Cloudy 12/07/13 - Overcast

Report No: LW24146

APPENDIX B Geotechnical Laboratory Testing Notes

Laboratory Test Results i) Geotechnical Testing ii) Contamination Testing

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).

Job No:

Sheet No:

MOISTURE CONTENT SUMMARY

WS4 3.00 22 CHALK.

RemarksVisual Description of Sample

Swanborough Farm

Swanborough

Lewes, East Sussex

BN73PF

ASHDOWN SITE INVESTIGATION LTDGeotechnical and Geoenvironmental Engineers

LW24146

1 of 1Seaford Head Sixth Form, Steyne Road, Seaford, East SussexSite:

BH/TP No. Depth (m)Natural Moisture Content

(w %)

WS1 3.00 10

Test Method: Moisture Content BS1377: Part 2: 1990 3.2

Fine Medium Coarse Fine Medium Coarse Fine Medium Coarse

Job Name BH/ TP No. WS1

Job No. LW24146Sample

Depth (m)1.35

Swanborough Farm

Swanborough

Lewes, East Sussex

BN73PF

ASHDOWN SITE INVESTIGATION LTDGeotechnical and Environmental Engineers

GRAVELSANDSILT

CO

BB

LE

CLAY

Particle Size Distribution by Wet Sieve; BS1377: Part 2 1990

Sample

Description

Seaford Head Sixth Form, Steyne Road, Seaford,

East SussexClayey SAND.

60 2 0.06 0.002 20 6 0.6 0.2 0.02 0.006

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.0001 0.001 0.01 0.1 1 10 100

Perc

en

tag

e P

assin

g

Particle Size (mm)




Depth (m)2.00

Swanborough Farm

Swanborough

Lewes, East Sussex

BN73PF


GRAVELSANDSILT

CO

BB

LE

CLAY


Sample

Description


East SussexClayey SAND.

60 2 0.06 0.002 20 6 0.6 0.2 0.02 0.006

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.0001 0.001 0.01 0.1 1 10 100

Perc

en

tag

e P

assin

g

Particle Size (mm)




Depth (m)1.10

CO

BB

LE

CLAY


Sample

Description


East SussexSilty SAND.

Swanborough Farm

Swanborough

Lewes, East Sussex

BN73PF


GRAVELSANDSILT

60 2 0.06 0.002 20 6 0.6 0.2 0.02 0.006

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.0001 0.001 0.01 0.1 1 10 100

Perc

en

tag

e P

assin

g

Particle Size (mm)




Depth (m)2.00

Swanborough Farm

Swanborough

Lewes, East Sussex

BN73PF


GRAVELSANDSILT

CO

BB

LE

CLAY


Sample

Description


East SussexClayey very sandy GRAVEL.

60 2 0.06 0.002 20 6 0.6 0.2 0.02 0.006

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.0001 0.001 0.01 0.1 1 10 100

Perc

en

tag

e P

assin

g

Particle Size (mm)




Depth (m)1.00

Swanborough Farm

Swanborough

Lewes, East Sussex

BN73PF


GRAVELSANDSILT

CO

BB

LE

CLAY


Sample

Description


East SussexSilty SAND.

60 2 0.06 0.002 20 6 0.6 0.2 0.02 0.006

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.0001 0.001 0.01 0.1 1 10 100

Perc

en

tag

e P

assin

g

Particle Size (mm)

Unit A2

Windmill Road

Ponswood Industrial Estate

St Leonards on Sea

East Sussex

TN38 9BY

Telephone (01424) 718618

Facsimile (01424) 729911

F.A.O. David Harris Reporting Date: 11 July 2013


The Old Dairy, Swanborough Farm

Swanborough, Lewes,

East Sussex, BN7 9PF

Samples Received By: Laboratory Courier

Sample Receipt Date: 04/07/13

Your Job No: LW24146

Your Order No: 130413

Site Location: Seaford Head 6th Form, Steyne Road, Seaford

No Samples Received: 3

Date of Sampling: 04/07/13

This report was written by: N. Williams

Authorised By;

John Wilson

Project & Business Development

Manager (CChem, MRSC)

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

2683

THE ENVIRONMENTAL LABORATORY LTD

ANALYTICAL REPORT No. AR45323

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

2683 Your Job No: LW24146


F.A.O. David Harris Reporting Date: 11/07/13



Swanborough, Lewes,


Soils

Characteristic Sand Sand Sand

TP/BH WS1 WS4 WS5

Depth (m) 2.00 1.00 2.60

Our ref 76447 76448 76449

pH Value** (Units) 8.3 8.5 8.5

Water Soluble Sulphate (mg/l as SO4) <20 <20 <20

All results expressed on dry weight basis

** - MCERTS accredited test

N. Williams


Location: Seaford Head 6th Form, Steyne Road, Seaford

Tel: 01424 718618 Fax: 01424 729911


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


St Leonards on Sea

East Sussex

TN38 9BY

Telephone (01424) 718618

Facsimile (01424) 729911


SAMPLE RECEIPT AND TEST DATES

Our Analytical Report Number AR45323



Reporting Date: 11/07/13

Registered: 04/07/13

Prepared: 05/07/13

Analysis complete: 11/07/13

TEST METHOD SUMMARY

PARAMETER Analysis Date Tested Method Technique

Undertaken on Number

pH Value** Air dried sample 09/07/13 113 Probe

Water Soluble Sulphate Air dried sample 09/07/13 209 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

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

2683

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

Unit A2

Windmill Road


St Leonards on Sea

East Sussex

TN38 9BY

Telephone (01424) 718618

Facsimile (01424) 729911

F.A.O. David Harris Reporting Date: 12 July 2013



Swanborough, Lewes,


Samples Received By: Laboratory Courier




Site Location: Seaford Head 6th Form, Steyne Road, Seaford, East Sussex

No Samples Received: 5

Date of Sampling: 04/07/13

This report was written by: Stuart Ballard

Authorised By;

John Wilson

Project & Business Development

Manager (CChem, MRSC)

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

2683



The Environmental Laboratory Ltd. Reg. No: 3882193 Page 1 of 6






Swanborough, Lewes,


Soils Characteristic Sandy Silt

loam

Silt loam Sandy Silt

loam

Sandy Silt

loam

Sandy Silt

loamTP/BH WS1 WS2 WS3 WS5 TP1

Depth (m) 0.50 0.50 0.50 0.40 - 0.60 0.30

Our ref 76442 76443 76444 76445 76446

Stone Content (%) 13 8 23 13 21

Arsenic** (mg/kg) 9.9 12.4 5.6 7.9 10.3

Cadmium** (mg/kg) <0.5 <0.5 <0.5 <0.5 <0.5

Chromium** (mg/kg) 33 35 29 30 25

Lead** (mg/kg) 104 138 9 42 1992

Mercury** (mg/kg) <0.5 0.6 <0.5 <0.5 <0.5

Nickel** (mg/kg) 10 17 5 12 11

Copper** (mg/kg) 21 47 6 16 26

Zinc** (mg/kg) 55 99 27 47 170

Selenium** (mg/kg) <0.5 0.7 <0.5 <0.5 0.5

Hexavalent Chromium (mg/kg) <2 <2 <2 <2 <2

Water Soluble Boron (mg/kg) 0.7 2.1 0.8 0.9 <0.5

pH Value** (Units) 8.4 8.0 8.3 8.1 8.2

Soil Organic Matter* (%) 2.6 3.3 2.9 3.5 3.2



* - UKAS accredited test

Stuart Ballard


Location: Seaford Head 6th Form, Steyne Road, Seaford, East Sussex

Tel: 01424 718618 Fax: 01424 729911


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







Swanborough, Lewes,


Soils

Characteristic Sandy Silt

loam


loam

Sandy Silt

loam

Sandy Silt


Depth (m) 0.50 0.50 0.50 0.40 - 0.60 0.30

Our ref 76442 76443 76444 76445 76446

Naphthalene** (mg/kg) <0.5 <0.5 <0.5 <0.5 <0.5

Acenaphthylene** (mg/kg) <0.5 <0.5 <0.5 <0.5 <0.5

Acenaphthene** (mg/kg) <0.5 <0.5 <0.5 <0.5 <0.5

Fluorene** (mg/kg) <0.5 <0.5 <0.5 <0.5 <0.5

Phenanthrene** (mg/kg) <0.5 <0.5 1.3 <0.5 <0.5

Anthracene** (mg/kg) <0.5 <0.5 <0.5 <0.5 <0.5

Fluoranthene** (mg/kg) <0.5 <0.5 2.7 <0.5 1.0

Pyrene** (mg/kg) <0.5 <0.5 2.3 <0.5 0.9

Benz(a)anthracene** (mg/kg) <0.5 <0.5 1.1 <0.5 <0.5

Chrysene** (mg/kg) <0.5 <0.5 1.4 <0.5 0.7

Benzo(b)fluoranthene** (mg/kg) <0.5 <0.5 0.8 <0.5 <0.5

Benzo(k)fluoranthene** (mg/kg) <0.5 <0.5 1.2 <0.5 0.8

Benzo(a)pyrene** (mg/kg) <0.5 <0.5 1.1 <0.5 0.6

Indeno(123-cd)pyrene** (mg/kg) <0.5 <0.5 1.0 <0.5 0.8

Dibenz(ah)anthracene** (mg/kg) <0.5 <0.5 <0.5 <0.5 <0.5

Benzo(ghi)perylene** (mg/kg) <0.5 <0.5 0.8 <0.5 0.6

Total PAH** (mg/kg) <0.5 <0.5 13.6 <0.5 5.3



Stuart Ballard


THE ENVIRONMENTAL LABORATORY LTDUnit A2, Windmill Road, Ponswood Industrial Estate, St Leonards On Sea, East Sussex, TN38 9BY

Tel: 01424 718618 Fax: 01424 729911








Swanborough, Lewes,


Soils

Characteristic Sandy Silt

loam


loam

Sandy Silt

loam

Sandy Silt


Depth (m) 0.50 0.50 0.50 0.40 - 0.60 0.30

Our ref 76442 76443 76444 76445 76446

C8-C10 (mg/kg) <5 <5 <5 <5 <5

>C10-C12 (mg/kg) <5 <5 <5 <5 <5

>C12-C16 (mg/kg) <5 <5 <5 <5 <5

>C16-C21 (mg/kg) <5 <5 <5 <5 <5

>C21-C35 (mg/kg) <5 <5 <5 <5 <5

Total Petroleum Hydrocarbons** (mg/kg) <5 <5 <5 <5 <5

Accredited for TPH only, not banding



Stuart Ballard


THE ENVIRONMENTAL LABORATORY LTDUnit A2, Windmill Road, Ponswood Industrial Estate, St Leonard's on Sea, East Sussex, TN38 9BY

Tel: 01424 718618 Fax: 01424 729911



2683

F.A.O. David Harris

Ashdown Site Investigation Limited Your Job No: LW24146

The Old Dairy, Swanborough Farm Your Order No: 130412

Swanborough, Lewes, Reporting Date: 12/07/13


Sample ref: WS1

Depth (m) 0.50

Our ref: 76442

#Description of Sample Matrix: Sandy Silt loam

*Result No asbestos identified

Sample ref: WS2

Depth (m) 0.50

Our ref: 76443

#Description of Sample Matrix: Silt loam


Sample ref: WS3

Depth (m) 0.50

Our ref: 76444



Sample ref: WS5

Depth (m) 0.40 - 0.60

Our ref: 76445



Sample ref: TP1

Depth (m) 0.30

Our ref: 76446



*= UKAS accredited

Analytical result only applies to the sample as submitted by the client

Any comments, opinions or interpretations (marked #) in this report are outside UKAS accreditation (Accreditation No2683). They are subjective comments only

which must be verified by the client

Stuart Ballard


Asbestos Identification

THE ENVIRONMENTAL LABORATORY LTDUnit A2, Windmill Road, Ponswood Industrial Estate, St Leonards On Sea, East Sussex, TN38 9BY

Tel: 01424 718618 Fax: 01424 729911


5 of 6

Unit A2

Windmill Road


St Leonards on Sea

East Sussex

TN38 9BY

Telephone (01424) 718618

Facsimile (01424) 729911


SAMPLE RECEIPT AND TEST DATES

Our Analytical Report Number AR45322



Reporting Date: 12/07/13

Registered: 04/07/13

Prepared: 05/07/13

Analysis complete: 12/07/13

TEST METHOD SUMMARY

PARAMETER Analysis Date Tested Method Technique

Undertaken on Number

Arsenic** Air dried sample 09/07/13 118 ICPMS

Cadmium** Air dried sample 09/07/13 118 ICPMS

Chromium** Air dried sample 09/07/13 118 ICPMS

Lead** Air dried sample 09/07/13 118 ICPMS

Mercury** Air dried sample 09/07/13 118 ICPMS

Nickel** Air dried sample 09/07/13 118 ICPMS

Copper** Air dried sample 09/07/13 118 ICPMS

Zinc** Air dried sample 09/07/13 118 ICPMS

Selenium** Air dried sample 09/07/13 118 ICPMS

Hexavalent Chromium As submitted sample 09/07/13 110 Colorimetry

Water Soluble Boron Air dried sample 09/07/13 202 Colorimetry

pH Value** Air dried sample 09/07/13 113 Probe

Soil Organic Matter* Air dried sample 09/07/13 111 Titration

Asbestos* As submitted sample 11/07/13 179 See note

Speciated PAH** As submitted sample 08/07/13 133 Gas Chromatography

Carbon Banding (TPH BCB)** As submitted sample 08/07/13 117 Gas Chromatography

Asbestos analysis qualitative only

Note:- Documented In-house procedure based on HSG 248 2005

* = UKAS Accredited test


Determinands not marked with * or ** are not accredited

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

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 6 of 6

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