PHASE II GEO-ENVIRONMENTAL SITE INVESTIGATION Clitheroe … · 2014. 8. 14. · Geo-Environmental Investigation August 2013 Former Pendle Garage 45024p1r0 Page 3 of 33 EXECUTIVE SUMMARY

National Consultancy, Locally Delivered

PHASE II GEO-ENVIRONMENTAL SITE INVESTIGATION Former Pendle Garage Clitheroe Road Barrow Lancashire REC Report: 45024p1r0 Issued: August 2013 Prepared for:

Geo-Environmental Investigation August 2013 Former Pendle Garage 45024p1r0

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QUALITY ASSURANCE

REC Offices Manchester Osprey House Pacific Quay Broadway Manchester M50 2UE Tel: 0161 868 1300

London Stansted Environment House Bullock Lane Takeley Bishop’s Stortford Hertfordshire CM22 6TA Tel: 01279 879 416

Birmingham Unit 19 Bordesley Trading Estate Bordesley Green Road Birmingham B8 1BZ Tel: 0121 326 7007

Dundee Unit 1.7 Discovery House Gemini Crescent Dundee DD2 1SW Tel: 01382 561 985

Plymouth Unit 13, Barn Close, Langage Business Park Plymouth Devon PL7 5HQ Tel: 0844 561 6735

Swindon Unit 58, Shrivenham Hundred Business Park Majors Road Watchfield Swindon SN6 8TY Tel: 01793 784 935

Newcastle Unit 20, Hubway House Bassington Industrial Estate Bassington Lane Cramlington Northumberland NE23 8AD Tel: 0167 0700 927

Northern Ireland 69A Killyman Street Moy County Tyrone BT71 7EA Tel: 02887 789 180

Southampton Environment House Segensworth Business Centre Segensworth Road (West) Fareham Hampshire PO15 5RQ Tel: 01329 847 783

Cardiff Unit1, Phase 11 Greenmeadow Spring Business Park Tongwynlais Cardiff Wales CF15 7AB Tel: 02920 529 822

Glasgow 16 Langlands Place Kelvin South Business Park East Kilbride Glasgow G75 0YF Tel: 01355 573 350

London 85 Tottenham Court Road London W1T 4TQ Tel: 02034 022 352

Port Talbot Unit 19 Kenfig Industrial Estate Margam Port Talbot SA13 2PE Tel: 01659 749 823

Stirling 11 Murchison Park Doune Stirling FK16 6AY Tel: 0845 676 9303

www.recltd.co.uk

Issue/revision Issue 1 Revision 1 Revision 2

Remarks Draft

Date August 2013

Prepared by A.Edgar

Qualifications BSc (Hons), MSc, AIEMA

Signature

Checked by D. Cox

Qualifications BSc (Hons), FGS, AIEMA

Signature

Authorised by M. Dyer

Qualifications BSc (Hons), CEnv, FGS,

AIEMA, M IEnvSc

Signature

Project number 45024

Doc. Ref – QR5-2 Issued – March 2013 By – A Edgar


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EXECUTIVE SUMMARY

Site Address Former Pendle Garage, Clitheroe Road, Barrow, Lancashire

Grid Reference E373610, N437550

Site Area 0.6ha

Current Site Use

Historically the site was utilised as a petrol filling station and for motor vehicle repairs. The site is no longer is use, and is a vacant plot of land with only the former shop still located on site. The associated fuel tanks are located immediately south of the filling station shop and are currently empty.

Site History The site remained largely undeveloped (presumed agricultural) until 1932, when a garage building was identified on site. The garage is no longer is use, pump islands have been removed; however the tanks still remain in-situ.

Geology Drift - Till, Devensian – Diamicton - Unproductive Solid - Clitheroe Limestone Formation And Hodder Mudstone Formation – Secondary A

Previous Reports

RSK previously completed a Preliminary Environmental Risk Assessment at the subject site, (referenced 321139-1 (00)) dated July 2012.

RSK identified dark staining in the proximity of an open ended pipe discharging onto the ground from the wall of the garage in the southeast corner. Small fragments of cement bonded asbestos sheeting were present on the ground across the yard area during the site walkover.

RSK confirmed that no radon protection measures are necessary in the construction of new dwellings at the site.

The Initial Conceptual Site Model (ICSM) identified a number of potential contaminative sources across the site comprising:

Heavy metals within the forecourt area, workshops and potential Made Ground of unknown origin;

Fuel and lubricating oils from the tank farm, forecourt, workshop and Made Ground from unauthorised disposal;

Potential Volatile Organic Compounds from solvents that may have been used for cleaning parts and potential migration from the industrial park in close proximity to the site;

Asbestos containing Materials within the building fabric and scattered across the site from either residual demolition or unauthorised disposal;

Acids and Sulphates within the Made Ground that may have been imported to site;

Polychlorinated biphenyls from the sub-station located off site, it is in REC’s opinion that this is an unlikely source due to the distance away from the site and the low mobility of PCB’s; and

The potential for Ground Gas Generation from Made Ground across the site.

Intrusive Ground Investigation

Ground Conditions

Approximately 5% of the site is covered by concrete hard standing (surrounding the pump islands), 20% with well-maintained asphalt, 50% poor condition asphalt and 6F2 type material and 25% covered in vegetation in the far eastern sector. Made Ground, typically comprising brown grey to black, clayey gravel was encountered in all exploratory hole locations from the ground level or beneath


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surface materials to a maximum depth of 1.20m bgl with an average thickness of circa 0.8m. Drift deposits comprising firm to stiff moderate to high strength CLAY was encountered within all exploration locations to a maximum proven depth of 3.12m bgl.

Groundwater was not encountered during the ground investigation.

Tier 1 Contaminated Land Risk Assessment

Human Health

The Tier I Human Health Risk Assessment has identified elevated concentrations of benzo(a)pyrene, benzo(a)anthracene and asbestos fibres. The identified constituents of concern pose a theoretical risk to human health through dermal contact, ingestion and inhalation of dust both during construction and following completion within garden and landscaped areas. The risk to construction workers can be mitigated through the adoption of safe working practices and provision of appropriate PPE. Careful consideration of the construction phase works will also reduce the likely generation of dust which will prevent possible exposure to adjacent properties. The risk to end users can be mitigated through the provision of a cover system with garden areas.

Controlled Waters The Tier I controlled water assessment identifies that there is unlikely to be a significant impact due to the low solubility of the compounds recorded and low sensitivity of the site with respect to controlled waters receptors.

Eco-toxic No significant concentrations of potentially eco-toxic contaminants have been identified.

Ground Gas Characteristic Situation 2 / Amber 1 – Ground (Pending the remaining scheduled ground gas monitoring visits).

Potable Water Infrastructure

The site is likely to require a hydrocarbon resistant potable water supply.

Geotechnical Assessment

Underground Obstructions

Relic foundations associated with the existing building in the western sector of the site may need to be removed to facilitate the installation of any proposed infrastructure; however as it is not currently within the footprint of a proposed plot this may not be required. The tanks are also located outside of any of the proposed residential dwelling footprints; however they will need to be removed in their entirety with validation samples collected to ensure no residual contamination is present beneath the tank areas. The vehicle inspection ramps will require to be removed along with all of the former service lines located across the site to facilitate the development.

Allowable Bearing Capacity

Assuming the current levels are utilised we consider that conventional standard shallow spread foundations placed within the firm gravelly CLAY at a depth of circa 1.00m bgl, deepened locally (maximum depth of 2.50m bgl) where required due to the presence of trees. At these depths an allowable bearing capacity in excess of 85kN/m² has been calculated for the clay.

Foundation Options

Traditional shallow spread with suspended Floor Slab in central areas of the site. Due to the close proximity of trees to the plots on the surrounding boundary line, strip footings may require a stepped foundation extending to a mass trench fill foundation or mini pile.

Soak-away Drainage

Not Recommended, due to very low permeability of soil.

Sulphate Assessment

Sulphate Class DS-1, (ACEC) AC-1s

CBR Design % Anticipated to be in excess of 2%, Plate Load Testing is recommended to confirm.


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Cut / Fill It is recommended that a detailed Isopachytes drawing is completed to calculate the required cut/fill required during the site enabling works.

Waste Classification

Likely to be stable non reactive non hazardous – Pending the recommended asbestos quantification by volume.

Recommendations

It is recommended that a full three dimensional earthworks cut / fill model with Isopachyte height banding should be developed to assess the earthworks mass balance for the project to achieve the required formation level and assess the requirement for import / export of bulk material. It is recommended that a Materials Management Plan (MMP) be developed to ensure a development led solution that ensures this material is retained on-site or exported to a donor site through the CL:AIRE Protocol. Preparation of a Remedial Strategy for the safe removal of the USTs and former petrol station infrastructure will be required for the site.


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TABLE OF CONTENTS

QUALITY ASSURANCE 2

EXECUTIVE SUMMARY 3

1.0 INTRODUCTION 8

1.1 Background 8 1.2 Current Site Layout 8 1.3 Proposed Development 8 1.4 Objectives 8 1.5 Limitations 9 1.6 Confidentiality 9

2.0 SITE INVESTIGATION 10

2.1 Desk Study Information 10 2.2 Ground Investigation 11

2.2.1 General 11 2.2.2 In-Situ Standard Penetration Testing (SPT) 12

2.3 Chemical Laboratory Analysis 12 2.4 Geotechnical Laboratory Testing 12

3.0 GROUND AND GROUNDWATER CONDITIONS 13

3.1 Ground Conditions 13 3.1.1 Summary of Ground Conditions 13 3.1.2 Made Ground 13 3.1.3 Drift Deposits 13 3.1.4 Solid Geology 13 3.1.5 Soil Consistency 14 3.1.6 Side Stability and Ease of Excavation 14 3.1.7 Soil Plasticity 17 3.1.8 pH and Sulphate 17

3.2 Groundwater Conditions 17 3.3 Ground Gas 17

4.0 TIER 1 QUALITATIVE CONTAMINATED LAND RISK ASSESSMENT 20

4.1 Human Health Risk Assessment 20 4.2 Controlled Waters 23 4.3 Ground Gas 24 4.4 Conceptual Model 26

5.0 GEOTECHNICAL ASSESSMENT 27

5.1 Proposed Development 27 5.2 Summary of Ground Conditions 27 5.3 Site Preparation 27 5.4 Foundation Conditions and Bearing Capacity 28 5.5 Ground Floor Slabs 31 5.6 Pavement Construction 31 5.7 Drainage 31 5.8 Concrete Durability 31 5.9 Excavations 31 5.10 Re-Use of Materials 31 5.11 Minerals 31 5.12 Further Works 31 5.13 Construction Activity and Inspection 32

6.0 CONCLUSIONS & RECOMMENDATIONS 33


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APPENDICES

Appendix I Limitations Appendix II Glossary Appendix III Drawings Drawing No 45024p1/001 – Site Location Plan Drawing No 45024p1/002 – Existing Site Layout Drawing No 45024p1/003 – Proposed Development Drawing No 45024p1/004 – GPR Survey

Drawing No 45024p1/005 – Exploratory Hole Location Plan Drawing No 45024p1/006 – Depth of Made Ground Drawing No 45024p1/007 – Historical Features Plan Drawing No 45024p1/008 – Development Constraints Plan Drawing No 45024p1/009 – Foundation Zoning Plan Appendix IV Photographs Appendix V REC Exploratory Hole Logs Appendix VI Chemical Testing Results Appendix VII Origin of Generic Assessment Criteria Appendix VIII Geotechnical testing results Appendix IX Supporting Documentation A CD containing all relevant environmental database information, historical & geological mapping and a complete PDF version of this report is attached to hard copy of the report.


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1.0 INTRODUCTION 1.1 Background Resource and Environmental Consultants (REC) Ltd have been commissioned by Bowsall Ltd to undertake a Phase II Intrusive Geo-Environmental Site Investigation at the former Pendle Garage, Clitheroe Road, Barrow, Lancashire. A Site location plan is presented as drawing 45024p1r0-001 The scope of work consisted of an intrusive Ground Investigation, comprising ground penetrating radar (GPR) survey, window sample probeholes with the installation of environmental monitoring installations and mechanically excavated trial pits. This was supplemented with laboratory chemical and geotechnical testing and interpretive report. 1.2 Current Site Layout The site is a broadly east-west orientated rectangular plot that consists of a former petrol filling station and work shop in the west and area of open land in the east. The former PFS appears to have a tank farm and two former pump islands that are likely to be connected by underground pipework. Manholes and vent pipes indicate that there are four, direct fill Underground Storage Tanks (USTs) located to the south of the workshop. The pump islands are still visible though the pumps have been removed. The forecourt area is constructed with concrete which was observed to be in a good condition and free of any visible staining or scarring. Approximately 5% of the site is covered by concrete hard standing (surrounding the pump islands), 20% with well-maintained asphalt, 50% poor condition asphalt and 6F2 type material and 25% covered in vegetation in the far eastern sector. To the north of the work-shop is a vehicle inspection ramp. No significant staining or spillages were noted at the site of the site inspection. The open land in the east of the site, slopes gently to the east and appears to be surfaced with loose or broken asphalt. There is evidence of fly-tipping in the area with small piles of building rubble noted. Fragments of potential asbestos containing materials are visible at ground level in the eastern sector of the site. An existing site layout plan is presented as drawing 45024p1r0-002 and a pre investigation constraints plan is presented as drawing 45024p1r0-008 Appendix III. 1.3 Proposed Development REC Ltd understands that Bowsall Limited propose to redevelop the site at the former Pendle Garage in Barrow for affordable residential housing units, that will comprise circa 24 low rise dwellings with associated gardens, driveways, roads and public open space. A Proposed Development Plan is presented as drawing 45024p1r0-003 in Appendix III.

1.4 Objectives The objectives of the geo-environmental investigation are to:


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Undertake a preliminary stage of Ground Investigation and analysis to provide an overview of conditions identified;

Assess the implications of any potential environmental risks, liabilities and development constraints associated with the site in relation to the future use of the site and in relation to off-site receptors;

Assess the geotechnical information and provide preliminary recommendations in relation to foundations, pavement construction and floor slabs;

Provide an assessment of the soakage of the underlying soils to assist in the design of infiltration based SuDS; and,

Provide recommendations regarding future works required.

1.5 Limitations The limitations of this report are presented in Appendix I. All acronyms used within this report are defined in the Glossary presented in Appendix II. 1.6 Confidentiality REC has prepared this report solely for the use of the Client and those parties with whom a warranty agreement has been executed, or with whom an assignment has been agreed. Should any third party wish to use or rely upon the contents of the report, written approval must be sought from REC; a charge may be levied against such approval.


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2.0 SITE INVESTIGATION 2.1 Desk Study Information RSK has previously completed a Preliminary Environmental Risk Assessment at the subject site, (referenced 321139-1 (00)) and dated July 2012. The salient features of the RSK Report are summarised below:

The site occupies an area of approximately 0.6Ha and is situated at an elevation of approximately 70m AOD;

Currently the site is occupied by a disused petrol filling station and a small area of neglected farmland at the rear. It is understood that the garage buildings are still occupied and waste materials were present within the yard area during the RSK site walkover;

It is understood that the pump islands have been removed; however the tanks and fuel pipes are still present. Both diesel and unleaded petrol were stored in the UST’s;

RSK identified dark staining in the proximity of an open ended pipe discharging onto the ground from the wall of the garage in the southeast corner;

Small fragments of cement bonded asbestos sheeting were present on the ground across the yard area, this was also noted during the REC site walkover. It was noted by RSK that potential asbestos containing materials were present in the fabric of the industrial units to the north of the site;

The grassed area to the front of the plot of land showed signs of poor drainage and vegetation including horsetail;

A number of large trees are present within the boundary hedges of the site; consideration should be given to the potential for ecological issues and the potential deepening of foundation, dependant on the soil mechanics of the underlying geology;

RSK confirmed that no radon protection measures are necessary in the construction of new dwellings at the site;

A landfill is located circa 600m north of the site, accepting Inert Wastes according to the environmental database. It is considered that the risk of ground gas is low due to the underlying geology;

The superficial deposits are classified as unproductive and the underlying solid geology is characterised as a Secondary A Aquifer, RSK stated that the soils beneath the site have a low leaching potential;

A small stream is mapped flowing southwest of the adjacent industrial park and is culverted circa 10m northwest of the filling station site; and,

The site remained largely undeveloped (presumed agricultural) until 1932, when a garage building was identified on site.

The Initial Conceptual Site Model (ICSM) produced by RSK identified a number of potential contaminative sources across the site comprising and these are listed in Table 2.1 overleaf: It is in REC’s opinion that Polychlorinated biphenyl (PCB) from the sub-station located off site is an unlikely source due to the distance away from the site and the low mobility of PCB. A Historical Features Plan is presented as Drawing 45024p1r0-007 in Appendix III.


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Table 2.1 Summary of Potential Contaminant Sources

Potential Source Potential Contaminants Potential Impact

Made Ground from historical

developments at the site.

� Metals

� Asbestos

� Ground Gas

� Sulphates

� Human Health

� Human Health

� Human Health

� Building and Buried Structures

Underground Storage Tanks and Forecourt.

Petroleum Hydrocarbons

(fuel) Human Health & Controlled Waters

Workshop.

Volatile Organic Compounds

(degreasers, paints)

Hydrocarbons

(lubricating oils, waste oils)

Chlorinated and halogenated

organic compounds

Human Health and Controlled Waters

2.2 Ground Investigation 2.2.1 General A Ground Investigation has been designed based on the findings of the desk study with exploratory holes advanced to target specific potential contaminant sources summarised in Table 2.1 in addition to baseline conditions across the site. The investigation has also been used to collect geotechnical information to assist in the design and construction of the development. The Environmental Health Officer (EHO) at Ribble Valley Council was consulted to gain acceptance for the proposed scope of works. A copy of the EHO’s response of approval is included within Appendix IX. Prior to undertaking the intrusive works a Ground Penetrating Radar survey was completed in order to locate any underground structures. The GPR survey plan is presented in Drawing 45024p1r0-004 (Appendix III). Exploratory fieldwork was completed on the 27th June 2012. The works are summarised in Table 2.2. Table 2.2 Summary of Fieldwork

Potential Source/Rationale Location

Hole

Type Maximum

Depth

(m bgl)

Monitoring

Wells

Response

Zone

USTs

WS105

WS106

WS108

Probehole 2.10

0.5m to 1.8m

0.5m to 1.8m

0.5m to 2.0m

Forecourt

WS107

WS108

WS109

WS110

Probehole 2.08

0.5m to 2.0m

N/A

N/A

N/A

Workshop WS104

TP107

TP112

Probehole &

Trial Pit 3.07

0.5m to 2.9m

Baseline Made Ground

WS101

WS102

WS103

WS111

WS112

TP101-109

Probehole &

Trial Pit 3.12

N/A

N/A

1.0m to 3.0m

N/A

1.0m to 3.0m

N/A


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Notes m bgl – metres below ground level.

The sampling locations are illustrated in Drawing 45024p1r0-005 (Appendix III). The ground conditions encountered and details of monitoring well response zones are indicated on the logs which are provided in Appendix V. Return visits were made to monitor installations for groundwater level and gas concentrations. Soil and groundwater samples destined for chemical analysis were collected at regular intervals in appropriate sampling containers. All samples were subsequently stored in cooled boxes prior to submission to analytical laboratory. All samples were collected using appropriate PPE and sampling equipment that was cleaned at each sampling location. A detailed copy of REC Ltd sampling methodology, QA procedures and laboratory chain of custody forms can be provided upon request. 2.2.2 In-Situ Standard Penetration Testing (SPT) In-situ geotechnical testing was conducted using the Standard Penetration Test (SPT) and where the ground is granular, a 60o cone (SPT(C)) was used instead of the sampling tube. The testing was conducted using the Cone Penetration Test (CPT). The results are shown in the probehole logs in Appendix V, presented in Table 3.5 and discussed in Section 5.0.

2.3 Chemical Laboratory Analysis

Selected soil samples were submitted for a range of chemical analysis comprising, metals, pH, total sulphate, water soluble sulphate (2:1 extract), sulphide, cyanide, phenols, total and speciated poly-aromatic hydrocarbons (PAHs), asbestos, organic carbon, total and speciated petroleum hydrocarbon (TPH) and Semi-Volatile Organic Compounds (sVOC). Scientific Analysis Laboratories (SAL) Ltd of Manchester undertook the analytical work and the testing results are included in Appendix VI and discussed in Section 4.0. 2.4 Geotechnical Laboratory Testing Selected samples were submitted to PSL where the following geotechnical tests were undertaken:

Atterburg Limits Determinations; and,

Undrained Shear Strength;

Laboratory analysis sheets are included in Appendix VIII and are summarised in Section 5.0.


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3.0 GROUND AND GROUNDWATER CONDITIONS 3.1 Ground Conditions 3.1.1 Summary of Ground Conditions The ground investigation generally confirms the published geology and identifies the strata set out in Table 3.1 below: Table 3.1 Summary of Strata

Strata Typical Description Min Depth to Top of Strata

(m)

Max Depth to Top of Strata

(m)

Max Thickness

(m)

Made Ground

Brown and locally grey to black, clayey gravel. Gravel comprises medium to coarse, angular to sub-angular fragments of concrete, brick, lithorelicts and occasional metal.

Surface Surface 1.20

Clay

Firm to stiff brown grey gravelly sandy CLAY. Gravel is medium to coarse angular to rounded lithorelicts

0.50 2.30 Not proven

3.1.2 Made Ground Made Ground was encountered in all exploratory hole locations from the ground level or beneath surface materials to a maximum depth of 2.30m bgl and has been assessed as having an average thickness of 0.8m. The Made Ground thickness is presented in Drawing 45024p1r0-006 in Appendix III. Fragments of potentially Asbestos Containing Materials (ACM) were recorded in TP102 and TP108. No hydrocarbon odours or staining were noted during the ground investigation. 3.1.3 Drift Deposits Drift deposits comprising firm to stiff medium to high strength CLAY were encountered within all exploration locations directly beneath the Made Ground. The full thickness of the drift was not proven in any of exploration locations with the majority terminated when the stratum became impenetrable with the exploration methods used. 3.1.4 Solid Geology Possible bedrock was encountered within the majority of the exploratory holes between depths of circa 2.00 and 3.00m bgl. This can only be confirmed through the advancement of drilling rotary boreholes with core recovery. From experience of exploratory works in the area, It is in REC’s opinion that the material is likely to be weathered bedrock


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3.1.5 Soil Consistency

Undrained shear strength values measured using quick undrained triaxial tests. Results of the tests are presented in Table 3.2 and show the clay soils to vary between firm and stiff. Strength test data is generally consistent with the field descriptions of the soils given above.

Table 3.2 Summary of Undrained Shear Strength Test Results

Results of the Standard Penetration Tests, including undrained shear strengths derived from SPTs are included on Table 3.3. 3.1.6 Side Stability and Ease of Excavation The sides of the exploratory trial pit excavations appeared to be stable during excavation.

Location Sample Depth (m)

Lab Description Undrained Shear Strength (kN/m

2)

Consistency

WS101 0.6-1.0 Firm brown mottled grey slightly sandy CLAY

54 Firm


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Table 3.3 Cone Penetration Test Results

Boreholes Depth (m bgl)

(i)

Material Field Description

CPT/SPT “N” Value

Corrected “N” Value

(N1)60

Terzaghi & Peck Relative Density

(Sands)

Eurocode Soil strength

Consistency (BS5930)

Terzaghi & Peck Approximate Undrained Shear Strength (kN/m

2)

WS101

1.00 Clay 8.00 8.07 N/A Medium strength Stiff 40.33

2.00 Clay 24.00 21.92 N/A High strength Very Stiff 109.62

3.00 Clay 50.00 43.48 N/A Very high strength Very Stiff 217.41

WS102

1.00 Made Ground 12.00 12.10 Medium Dense N/A N/A N/A

2.00 Made Ground 25.00 22.84 Medium Dense N/A N/A N/A


WS103




WS104




WS105 1.00 Clay 19.00 19.15 N/A High strength Very Stiff 95.77


WS106 1.00 Clay 12.00 12.10 N/A Medium strength Stiff 60.49


WS107 1.00 Clay 34.00 34.28 N/A Very high strength Very Stiff 171.39








WS111 1.00 Clay 12.00 12.10 N/A Medium strength Stiff 60.49



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Boreholes Depth (m bgl)

(i)

Material Field Description

CPT/SPT “N” Value

Corrected “N” Value

(N1)60

Terzaghi & Peck Relative Density

(Sands)

Eurocode Soil strength

Consistency (BS5930)

Terzaghi & Peck Approximate Undrained Shear Strength (kN/m

2)

WS112





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3.1.7 Soil Plasticity

The Atterberg Limits determinations, summarised in Table 3.4 below, show the clay to be of low to intermediate plasticity. Natural Moisture Content is close to the Plastic Limit.

Table 3.4 Summary of Plasticity Index Test Results

3.1.8 pH and Sulphate Chemical analyses for pH and soluble sulphate content contained in Appendix VI (summarised below in Table 3.5), shows that the soils at the site generally meet Class DS-1, Aggressive Chemical Environment for Concrete Classification (ACEC) AC-1s in accordance with BRE Special Digest 1 (2005). Table 3.5 Summary of pH and Sulphate Data

Location Depth (m)

SO4 in 2:1 water / soil (g/l)

pH Value

WS105 0.3


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O2 were recorded. The results of the ground gas monitoring are presented in Table 8.6 overleaf..


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Table 8.6 Summary of Ground Gas and Groundwater Monitoring Results

Well Date CH4

Initial %v/v

CH4 Steady %v/v

CH4 GSV l/hr

CO2 Initial %v/v

CO2 Steady %v/v

CO2 GSV l/hr

O2 %v/v

Atmos(mb)

Atmos. Dynamic

Flow (l/hr)

Response Zone

(mbgl)

Depth to Base

(mbgl)

Depth to

Water (mbgl)

WS103

22/07/2013 0.10 0.10 0.0001 9.90 9.90 0.0099 10.50 1008.00 Steady 0.10

1.00-3.00

2.732 1.923

WS104

22/07/2013 0.10 0.10 0.0001 3.10 3.10 0.0031 17.50 1008.00 Steady 0.10

0.50-3.00

2.996 1.714

WS105

22/07/2013 0.10 0.10 0.0001 3.70 3.70 0.0037 15.60 1008.00 Steady 0.10

0.50-2.00

2.081 1.444

WS106

22/07/2013 0.10 0.10 0.0001 2.50 2.50 0.0025 16.60 1008.00 Steady 0.10

0.50-2.00

1.933 1.071

WS107

22/07/2013 0.10 0.10 0.0043 0.10 0.10 0.0043 18.30 1008.00 Steady 4.30

0.50-2.00

1.885 0.521

WS108

22/07/2013 0.10 0.10 0.0001 4.50 4.50 0.0045 13.80 1008.00 Steady 0.10

0.50-2.00

1.734 0.831

WS110

22/07/2013 0.10 0.10 0.0001 0.10 0.10 0.0001 19.20 1008.00 Steady 0.10

0.50-2.00

2.047 0.559


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4.0 TIER 1 QUALITATIVE CONTAMINATED LAND RISK ASSESSMENT REC has undertaken a Tier 1 qualitative risk assessment to determine if any potential contaminants within the underlying soils and groundwater pose an unacceptable level of risk to the identified receptors. 4.1 Human Health Risk Assessment At a Tier 1 stage the long term (chronic) human health toxicity of the soil has been assessed by comparing the on-site concentrations of organic and inorganic compounds with reference values published by the EA (Contaminated Land Exposure Assessment (CLEA) Soil Guideline Values (SGV)) and where absent, Generic Assessment Criteria (GACs) published by LQM/CIEH (2nd edition). The results of this comparison have been summarised within Table 4.1 (overleaf).


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Table 4.1 Summary of Inorganic and Hydrocarbon Toxicity Assessment for a Residential End Use

Determinand Units GAC V3

n MC Loc. of Ex

Pathway Assessment

Arsenic mg/kg 32 8 13 NA 1 No Further Action

Cadmium mg/kg 10 8 4 NA 1 No Further Action

Chromium (VI) mg/kg 4.3 8


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Determinand Units GAC V3

N MC Loc. of Ex

Pathway Assessment

TPH C16-C21 (aromatic) mg/kg 250 9 38 NA 1 No Further Action

TPH C21-C35 (aromatic) mg/kg 890 9 79 NA 1 No Further Action

Notes Main Exposure Pathways: 1 = Soil Ingestion, 2 = Vapour Inhalation (indoor), 3 = Dermal Contact & Ingestion, 4 = Dust Inhalation. Abbreviations: GAC = General Assessment Criteria, n = number of samples, MC = Maximum Concentration; Loc of Ex = Location of Exceedance. * The Tier 1 GAC for the hydrocarbon fraction is derived from the CIEH assessment for petroleum hydrocarbons Criteria Working Group (CWG) for both aliphatic and aromatic compounds. REC has utilised the Tier 1 values for aliphatic compounds for the volatile and semi volatile fractions (C5-C12) and the Tier 1 values for aromatic compound for the non-volatile fractions (C12-C35). The comparison of a total (aliphatic/aromatic) compounds to an individual fraction is considered to be a conservative approach and satisfactory for the protection of human health. (i) Benzo (b) Fluoranthene (100mg/kg) Benzo (k) Fluoranthene (140mg/kg) (ii) GAC based on human health criteria. Ecotoxicological assessment will be made using EA guidance (EPR

8.01) on soil spreading (Cu 135mg/kg, Zinc 200mg/kg, Pb 300mg/kg)

Further Assessment Sources Reviewing the available results it has been established that significant hydrocarbon or semi Volatile Organic Compound (sVOC) impact is not present within the vicinity of the former USTs, forecourt or workshop. Validation testing from beneath the USTs is recommended once they have been removed. Localised exceedances of benzo(a)anthracene and benzo(a)pyrene (BaP) have been identified in three of the nine samples tested with two of those being from with the Made Ground and one from the top of the underlying natural strata. A review of the logs does not indicate a specific hydrocarbon source to the BaP and an assessment of the ratios of the PAHs benzo(a)anthracene to chrysene and fluoranthene to pyrene indicates that the PAHs present within WS108 and TP103 are likely from a coal derived source, which presents less of risk to human health. The same assessment on the sample from TP104 indicates a possible combustion source to the PAH. Laboratory testing has confirmed the presence of asbestos within the Made Ground TP107 and presumed ACM has been identified within TP102 and TP108. Additional testing of the soils in these areas may help to demonstrate that the identified impact is localised only and not representative of the entire site. Pathways

Dermal contact and ingestion; and, Dust inhalation.


Page 23 of 33

Receptors Based on a future residential end use, the following receptors may be present:

Future construction workers; Future residential end users; and, Adjacent third parties.

Future Site Users In the case of all the contaminants of concern (asbestos and PAHs), the exposure pathway is dermal contact and ingestion and dust inhalation. It is considered that soft landscaping areas of the site will require a clean cover (approximately 600mm thick) to remove the pathway. Where hardstand is proposed (whether it is buildings or roadways) it will remove the direct pollutant linkage between the Made Ground and end users, and therefore, remove the risk. Chemical and physical verification of the clean cover will be required but based on the limited chemical testing undertaken on the deeper natural material, it is possible that material from the natural strata could be won and utilised for any required cover system through a process of soil inversion. Hydrocarbon resistant potable supply pipes are likely to be required within the proposed development. Construction and Maintenance Workers Construction workers involved in the ground works and construction during the site redevelopment are at risk from exposure to contaminated soils given their close proximity and contact with the soil which may result in a short term human health risk from the detected contaminants. The primary contaminant exposure pathways are considered to be dermal contact, indirect soil ingestion and inhalation of soils dusts and vapours. These risks can be reduced by appropriate PPE and hygiene precautions and good working practices. It is recommended that normal health and safety procedures be adopted by ground workers including no eating, drinking or smoking on-site, designated clean and wash areas and protective clothing. This report should be forwarded to the construction company undertaking the ground works in order for them to assess the risk to their personnel. Adjacent Site Users Adjacent site users may be potentially exposed on a short term basis (primarily through potential inhalation / ingestion of dust) to the Made Ground if it is disturbed during the redevelopment of the site. However, this could be adequately controlled by careful excavation of the material and standard dust control measures during redevelopment works. Due to the presence of asbestos within the Made Ground further quantification analysis recommended and if necessary a specific method statement produced for dealing with excavations in asbestos impacted soil. 4.2 Controlled Waters The underlying Clay stratum is classed as an unproductive and no groundwater abstractions are reported to be present within the immediate surrounding area. Furthermore, no


Page 24 of 33

groundwater was recorded at the site during the site investigation and subsequent monitoring has only identified limited perched water that was not present in sufficient volume to permit sampling. In order to determine whether hydrocarbons may pose a risk to controlled waters three samples, taken from adjacent to the former USTs and forecourt, were schedule for leachate tests. The results indicate that all concentrations were below the lower level of detection with the exception of C21-C35 aliphatic in WS105. As C21-C35 is considered to represent low solubility hydrocarbons, the result is considered to reflect the aggressive nature of the test rather than representative of what would be feasible in the environment. 4.3 Ground Gas The potential impact on the development from ground gases has been assessed with reference to standards and guidelines published in CIRIA Report 665 (Assessing risks posed by hazardous ground gases to buildings, 2007). However, it is recommended that the full ground gas assessment and recommended protection measures are agreed with the local authority prior to their adoption on-site. Furthermore, all protection measures adopted should be validated by a suitably qualified engineer. The Phase I report and subsequent ground investigation has identified the following potential sources of ground gas:

Made Ground from historical development. During the monitoring visit completed to date, no significantly elevated concentrations of methane were recorded within any of the probeholes. Elevated levels of carbon dioxide (up to 9.9% v/v) were recorded in WS103 though this was also associated with low flow rates of than 0.1litres/hr. In accordance with the methodology outlined with the CIRIA publication C665, REC have utilised the results of the ground gas monitoring surveys to calculate a tentative Gas Screening Value (GSV). The maximum GSV calculated for methane was 0.0043 l/hr (WS107) and for carbon dioxide was 0.0099 l/hr (WS103). The GSV has been compared to the criteria outlined with CIRIA C665 to determine the level of risk to the proposed development and to ensure the appropriate remedial options are incorporated into any future building design in this area. CIRIA C665 states that the maximum GSV for carbon dioxide and methane is


Page 25 of 33

This is an interim assessment based on preliminary ground gas readings, the final classification will be supplied as an addendum to this report on completion of the remaining monitoring visits.


Page 26 of 33

4.4 Conceptual Model Following the completion of the intrusive site investigation, chemical analysis and risk assessment the conceptual model shown in Table 4.2 has been prepared for the site. Table 4.2 Conceptual Model

Source Exposure Pathway

Potential Receptor

Probability of

Exposure

Discussion of Pollutant Linkage

Human Health

PAHs

Asbestos fibres

Dermal Contact & Ingestion

Dust Inhalation

Future Users Low/Medium

Analysis and field observations indicate that the PAH’s and ACM is present in various locations and not attributable to a single source or area. The exceedances have been associated with Made Ground; therefore a 600mm cover system in all areas of soft landscaping where it is proposed to retain Made Ground will remove the exposure pathways.

Construction Worker

Low

Construction workers can mitigate any risk through the use of appropriate PPE and safe working practices. Furthermore, the duration of any exposure is likely to be low and as such the risk is considered to be low.

Adjacent Property

Low/Medium

Careful excavation of any impacted soils and/or the use of dust suppression techniques will reduce the risk of dust generation and prevent off-site dust migration. The risk the adjacent properties are therefore considered to be low.

Ground Gas Inhalation

Accumulation Future Users Low

Limited results are currently available and further assessment will be required.

Controlled Water

No risk to controlled water has been identified.


Page 27 of 33

5.0 GEOTECHNICAL ASSESSMENT 5.1 Proposed Development It is understood that the proposed development will comprise 28 low rise residential units with landscaping to the front and rear, associated driveways and adoptable estate roads. REC drawing 45024-01-002 presented within Appendix III indicates the proposed planning layout for the site. Details of the proposed loadings are not known and therefore a line loading of 75kN/m has been assumed for preliminary assessment purposes only. Given the nature of the proposed development it is considered that the structure meets the criteria of Geotechnical Category 1 of Euro Code 7. Given the nature of the development it is considered that acceptable risk from settlement is a total settlement value of 25mm for a masonry structure. 5.2 Summary of Ground Conditions Ground conditions identified at the site are summarised in Table 5.1 below: Table 5.1 Summary of Ground Conditions

Strata Typical Description Min Depth to Top of Strata

(m)

Max Depth to Top of Strata

(m)

Max Thickness

(m)

Made Ground

Brown and locally grey to black, clayey gravel. Gravel comprises medium to coarse, angular to sub-angular fragments of concrete, brick, lithorelicts and occasional metal.

Surface Surface 2.30

Clay

Firm to stiff moderate to high strength brown grey gravelly sandy CLAY. Gravel is medium to coarse angular to rounded lithorelicts.

0.50 2.30 Not proven

5.3 Site Preparation The site should be cleared and any vegetation below areas of proposed development stripped in accordance with Series 200 of the Specification for Highway Works. This should include:

Roots present below the footprint of proposed structures and infrastructure should be grubbed out and the resulting void infilled with suitable compacted engineered fill;

Redundant services should be sealed off and grubbed out and replaced with suitable compacted engineered fill; and,

USTs are present on-site and these are to be excavated and removed from site. Once the resulting void has been chemically validated, the void should be backfilled with suitable compacted engineered fill.


Page 28 of 33

5.4 Foundation Conditions and Bearing Capacity General Chart 5.1 below shows the ABC derived from the SPT testing in cohesive strata, which are dominant at the site. Chart 5.1 – Allowable Bearing Capacity for Cohesive Strata

The ground conditions across the main development area of the site have been found to generally consist of a thin layer (average


Page 29 of 33

moderate to high water demand and as such, have dictated that foundations are deepened to prevent damage. Foundation footings are shown to range between 0.75m bgl and 2.50m bgl. Drawing No 45024-01-009 represents foundation footings depths based upon D/H of the mature height. Plots in the central areas of the site could be suitable for a standard strip footing at 0.90m bgl, however due to the close proximity of trees to the plots on the surrounding boundary line strip footings may require a stepped or piled foundation to mitigate any potential foundation issues. Atterberg limits determinations, summarised in Table 3.4 show the clay to be of intermediate plasticity (modified) and as such the sides of the foundations may require protection using clay board or similar.


Page 30 of 33

Table 5.2 Tree Influence in accordance with Chapter 4.2 NHBC 2013

Tre

e N

o

Sp

eci

es

Sta

tus

Wa

ter

De

ma

nd

Cla

ss

Re

mo

va

l /

Ma

ture

he

igh

t (H

)

So

il S

hri

nk

ag

e C

lass

Dis

tan

ce t

o S

S 0

.9m

Dis

tan

ce t

o F

oo

tin

g

1.2

5m

Dis

tan

ce t

o F

oo

tin

g

1.5

0m

Dis

tan

ce t

o F

oo

tin

g

1.7

5m

Dis

tan

ce t

o F

oo

tin

g

2.0

0m

Dis

tan

ce t

o F

oo

tin

g

2.2

5m

T1 Common Oak retained high 20 moderate 25.00 21.00 18.00 15.00 12.00 9.00

T2 Ash remove moderate 15.5 moderate 12.00 8.50 5.50 3.00 1.00 N/A

T3 Ash remove moderate 15 moderate 12.00 8.50 5.50 3.00 1.00 N/A

T4 Common Oak remove high 6 moderate 10.00 8.50 7.00 6.00 4.50 3.50

T5 Common Oak remove high 13 moderate 18.00 14.50 13.00 11.50 8.50 6.50

T6 Ash retained moderate 23 moderate 18.00 13.00 8.50 4.50 1.00 N/A

T7 Ash remove moderate 9 moderate 8.00 5.50 3.50 2.00 N/A N/A

G1 2 No. Leyland Cypress remove high 19 moderate 12.00 10.00 8.50 7.50 5.70 4.50

G2 9 No. Layland Cypress remove high 12 moderate 8.00 6.00 5.00 4.50 3.50 2.50

G3

4 No. Hawthorn, 2 No. Elder,

1 No. Hazel remove high 10 moderate 13.00 10.50 9.00 7.50 6.00 4.50

G4 9 No. Goat Willow remove high 6 moderate 10.00 8.50 7.00 6.00 4.50 3.50

G5 2 No. Ash remove moderate 6.5 moderate 6.00 4.50 2.50 1.50 N/A N/A

H1

Hawthorn, Hazel &

Blackthorn remove high 7 moderate 10.00 8.50 7.00 6.00 4.50 3.50

H2 Leyland Cypress remove high 5 moderate 5.00 4.00 3.50 2.90 2.50 2.00


Page 31 of 33

5.5 Ground Floor Slabs Due to the presence of substantial thickness’ of Made Ground the NHBC and Building control will require suspended floor slabs. Where suspended floor slabs are employed ventilation of the under floor void will be required to address condensation issues. 5.6 Pavement Construction A design CBR of less than 2% should be assumed for the Made Ground, although it may be possible to increase this following plate load tests and completion of a well designed enabling works package.

5.7 Drainage

The underlying clay is very low permeability. It is not considered suitable for the application of soakaway disposal of surface water runoff.

5.8 Concrete Durability Based upon the results of the chemical analyses summarised in Table 3.5 it is considered that subsurface concrete can be designed in accordance with Design Sulphate Class DS-1, Aggressive Chemical Environment for Concrete Classification (ACEC) AC-1s in accordance with the recommendations provided in BRE Special Digest 1 (2005).

5.9 Excavations

Site observations indicated that excavations should be feasible in the near surface with normal plant, however obstructions are likely to be present in the west of the site where a concrete forecourt, workshop and USTs are located. Due to the variability of the Made Ground it is considered that all excavations are supported or battered back in accordance with guidance contained in CIRIA RR97. 5.10 Re-Use of Materials Consideration has been given to the potential re-use of site won arising’s from foundation excavations, this material could be used for use as sub-soil within the clean cover system. This has been determined through:

Physical description of the soils encountered (variability and organic content); and,

Chemical Analysis. 5.11 Minerals There are no minerals of economic value underlying the Sites at shallow depth and mining is considered to be very unlikely. There are no mine entries recorded or likely at this site. The Site is considered to be minerally stable.

5.12 Further Works

The following additional works may be required:


Page 32 of 33

Delineation of impacted Made Ground;

Preparation of a Remedial Strategy for the safe removal of the USTs and former petrol station infrastructure;

Isopachyte Cut/Fill model;

Preparation of a Material Management Plan (MMP) regarding the safe and legally compliant re-use of site won materials if used within any future cover system; and,

Plate load testing to provide design CBR values for road and pavement areas. Materials Management Plan (MMP) The Materials Management Plan (MMP) is a document designed in accordance with the Development Industry Code of Practice (COP) “The Definition of Waste”, published by Contaminated Land: Application in Real Environments (CL:AIRE). The COP relates to the re-use of chemically and geotechnically suitable materials where a definitive need has been established as part of the development process. Plate Load Testing An assessment of the bearing capacity of the soil in respect to pavement and foundation design should be undertaken using the California Bearing Ratio (CBR) in order to allow the economic and safe design of access roads and suspended floor slabs; 5.13 Construction Activity and Inspection The following activities and inspections should be incorporated in to the site works:

It is considered that de-watering may be required, especially following periods of heavy rainfall. Removal of surface water and water within trenches should be possible with conventional sump pumping. Discharge of any water should be agreed with the relevant regulatory body and be undertaken under a trade effluent discharge, where required. Measures to remove silt and suspended solids may be required and consideration should be given to provision of space for settling tanks or an attenuation pond;

Where access to confined spaces is required appropriate mitigation measures should be addressed within the Construction Stage Health and Safety Plan. Particular account should be taken of the gas results;

The presence of potential contamination and mitigation measures should be addressed as part of the Construction Stage Health and Safety Plan and should include measures to design out the risks, reduce their impact and finally the use of Personnel Protective Equipment (PPE); and,

The presence of potential contamination and mitigation measures should be addressed as part of the Construction Stage Health and Safety Plan and should include measures to design out the risks, reduce their impact and finally the use of Personnel Protective Equipment (PPE).


Page 33 of 33

6.0 CONCLUSIONS & RECOMMENDATIONS

Geotechnical Assessment

It is considered that subject to the removal of the former USTs, relict structures, and locally deep Made Ground, ground conditions should allow for the construction of shallow strip foundations bearing on the underlying Clay.

Consideration should be given to the potential for physical change in clay due to the number of trees located on site.

It is recommended that conventional foundations are used founding on firm Clay; albeit subject to the proposed Final Finished Levels

Based upon the results of the chemical analyses for pH and soluble sulphate content, REC Ltd consider that all subsurface concrete should be designed in accordance with Design Sulphate Class DS-1, (ACEC) AC-1s.

Owing to the presence of trees, suspended floor slabs are recommended. It is considered that ventilation of the under floor void, required to prevent condensation.

It is anticipated that the underlying soils will be predominantly cohesive and as such are unlikely to provide a high degree of soakage potential for drainage systems. As soakaway drainage is not likely feasible then on-site attenuation of storm water may be required.

Revised Conceptual Site Model

The Tier I Human Health Risk Assessment has identified elevated concentrations of PAH’s and asbestos fibres. These may pose a risk to human health through dermal contact, ingestion and inhalation of dust both during construction and following completion within garden and landscaped areas. It is likely that the site will require barrier type A or B, depending on the required diamiter for water supply pipe work. The risk to construction workers can be mitigated through the adoption of safe working practices and provision of appropriate PPE. Careful consideration of the construction phase works will also reduce the likely generation of dust which will prevent possible exposure to adjacent properties. The risk to end users can be mitigated through the provision of a cover system with garden areas. The Tier I controlled water assessment identifies that there is unlikely to be a significant impact due to the low solubility of the compounds recorded and low sensitivity of the site with respect to controlled waters receptors. The ground gas assessment indicates a moderate risk to future site users but this is subject to further assessment.

Recommendations

It is recommended that a full three dimensional earthworks cut / fill model with Isopachyte height banding should be developed to assess the earthworks mass balance for the project to achieve the required formation level and assess the requirement for import / export of bulk material. It is recommended that a Materials Management Plan (MMP) be developed to ensure a development led solution that ensures this material is retained on-site or exported to a donor site through the CL:AIRE Protocol. Preparation of a Remedial Strategy for the safe removal of the USTs and former petrol station infrastructure will be required for the site.

END OF REPORT


APPENDIX I

LIMITATIONS AP

PE

ND

IX I

LIM

ITA

TIO

NS


1. This report and its findings should be considered in relation to the terms of reference and objectives agreed between REC Ltd and the Client as indicated in Section 1.2.

2. For the work, reliance has been placed on publicly available data obtained from the sources identified. The

information is not necessarily exhaustive and further information relevant to the site may be available from other sources. When using the information it has been assumed it is correct. No attempt has been made to verify the information.

3. This report has been produced in accordance with current UK policy and legislative requirements for land

and groundwater contamination which are enforced by the local authority and the Environment Agency. Liabilities associated with land contamination are complex and requires advice from legal professionals.

4. During the site walkover reasonable effort has been made to obtain an overview of the site conditions.

However, during the site walkover no attempt has been made to enter areas of the site that are unsafe or present a risk to health and safety, are locked, barricaded, overgrown, or the location of the area has not be made known or accessible.

5. Access considerations, the presence of services and the activities being carried out on the site limited the

locations where sampling locations could be installed and the techniques that could be used. 6. In addition to the above REC Ltd note that when investigating, or developing, potentially contaminated land it

is important to recognise that sub-surface conditions may vary spatially and also with time. The absence of certain ground, ground gas, and contamination or groundwater conditions at the positions tested is not a guarantee that such conditions do not exist anywhere across the site. Due to the presence of existing buildings and structures access could not be obtained to all areas. Additional contamination may be identified following the removal of the buildings or hard standing.

7. Site sensitivity assessments have been made based on available information at the time of writing and are

ultimately for the decision of the regulatory authorities. 8. Where mention has been made to the identification of Japanese Knotweed and other invasive plant species

and asbestos or asbestos-containing materials this is for indicative purposes only and do not constitute or replace full and proper surveys.

9. The executive summary, conclusions and recommendations sections of the report provide an overview and

guidance only and should not be specifically relied upon without considering the context of the report in full. 10. This report presents an interpretation of the geotechnical information established by excavation, observation

and testing. Whilst every effort is made in interpretative reporting to assess the soil conditions over the Site it should be noted that natural strata vary from point to point and that man made deposits are subject to an even greater diversity. Groundwater conditions are dependent on seasonal and other factors. Consequently there may be conditions present not revealed by this investigation.

11. REC can not be held responsible for any use of the report or its contents for any purpose other than that for

which it was prepared. The copyright in this report and other plans and documents prepared by REC is owned by them and no such plans or documents may be reproduced, published or adapted without written consent. Complete copies of this may, however, be made and distributed by the client as is expected in dealing with matters related to its commission. Should the client pass copies of the report to other parties for information, the whole report should be copied, but no professional liability or warranties shall be extended to other parties by REC in this connection without their explicit written agreement there to by REC.

12. Rather, this investigation has been undertaken to provide a preliminary characterisation of the existing sub-

surface geotechnical characteristics and make up and the findings of this study are our best interpretation of the data collected, within the scope of work and agreed budget. New information, revised practices or changes in legislation may necessitate the re-interpretation of the report, in whole or in part.

13. This investigation has been undertaken to reasonably characterise existing sub-surface conditions and the

findings of this study are our best interpretation of the data collected, within the scope of work and agreed budget. New information, revised practices or changes in legislation may necessitate the re-interpretation of the report, in whole or in part.


APPENDIX II

GLOSSARY

AP

PE

ND

IX II

GL

OS

SA

RY


TERMS

AST Above Ground Storage Tank

BGS British Geological Survey

BSI British Standards Institute

BTEX Benzene, Toluene, Ethylbenzene, Xylenes

CIEH Chartered Institute of Environmental Health

CIRIA Construction Industry Research Association

CLEA Contaminated Land Exposure Assessment

CSM Conceptual Site Model

DNAPL Dense Non-Aqueous Phase Liquid (chlorinated solvents, PCB)

DWS Drinking Water Standard

EA Environment Agency

EQS Environmental Quality Standard

GAC General Assessment Criteria

GL Ground Level

GSV Gas Screening Value

HCV Health Criteria Value

ICSM Initial Conceptual Site Model

LNAPL Light Non-Aqueous Phase Liquid (petrol, diesel, kerosene)

ND Not Detected

LMRL Lower Method Reporting Limit

NR Not Recorded

PAH Poly Aromatic Hydrocarbon

PCB Poly-Chlorinated Biphenyl

PID Photo Ionisation Detector

QA Quality Assurance

SGV Soil Guideline Value

SPH Separate Phase Hydrocarbon

Sp.TPH (CWG) Total Petroleum Hydrocarbon (Criteria Working Group)

SPT Standard Penetration Test

SVOC Semi Volatile Organic Compound

UST Underground Storage Tank

VCCs Vibro Concrete Columns

VOC Volatile Organic Compound

WTE Water Table Elevation

UNITS

m Metres

km Kilometres

% Percent

%v/v Percent volume in air

mb Milli Bars (atmospheric pressure)

l/hr Litres per hour

µg/l Micrograms per Litre (parts per billion)

ppb Parts Per Billion

mg/kg Milligrams per kilogram (parts per million)

ppm Parts Per Million


mg/m3 Milligram per metre cubed

m bgl Metres Below Ground Level

m bcl Metre Below Cover Level

mAOD Metres Above Ordnance Datum (sea level)

kN/m2 Kilo Newtons per metre squared

µm Micro metre


APPENDIX III

DRAWINGS

AP

PE

ND

IX III

DR

AW

ING

S

45024 30-07-13

R. Willoughby

Not To Scale

M. Dyer

Job No:

Drawn by:

Approved by:

Scale:

Notes: Drawing Title:Client:Job Title:

The client must not amend anydrawing, design or other intellectualproperty produced by REC Ltd.without permission in writing fromREC Ltd. in advance of anyamendments being made.

In the event that such writtenpermission is not obtained in advanceof the amendments being made, RECLtd. shall not be liable for any damageand/or losses occuring as a result ofthe amended drawing, design orintellectual property.

N

Pendle Garage,Clitheroe Road

Bowsall Ltd45024p1r0-001

Site Location Plan

1

2

4

3

32 1

4

3 4

2 1

4 3

1 2

1

2

4

3

1

2 3 2

4 1 4

3

4 3

1 234

1 234

1 21 2

4 3

GP 2B4P

GP 3B5P

GP

2B4P

Nursery

GP 2B4P

GP 2B4P

GP

2B4P

GP 2B4P

GP 3B5P

GP

2B4P

GP 3B5P

GP 2B4PGP 2B4P GP 2B4P

GP 3B5P

GP 3B5P

Exisiting Industrial Unit

718-PENDLE - OPTION 2 - CENTRAL ACCESS 1-500REVISION B - 05-08-13

area will require retainingstructure due to site levels

low maintenance plantingbuffer strip to industrial units

GP

2B4P

replacement tree planing to beagreed

GP 3B5P

Public House

Clitheroe Road

GP 2B4P

GP

2B4P

GP 3B5P

GP 2B4P GP 3B5P

GP 3B5P

GP 3B5P

GP 2B4P GP 3B5P

01

03

02

04

0506

07

0811

0910

12

13 14 15 16 1917 18

2120

22

GP 2B4P

GP 2B4P

2423

2526

2728

R. Willoughby

M. Dyer

Job No:

Drawn by:

Approved by:

Scale:

Notes: Drawing Title:Client:Job Title:

The client must not amend anydrawing, design or other intellectualproperty produced by REC Ltd.without permission in writing fromREC Ltd. in advance of anyamendments being made.

In the event that such writtenpermission is not obtained in advanceof the amendments being made, RE CLtd. shall not be liable for any damageand/or losses occuring as a result ofthe amended drawing, design orintellectual property.

N

45024p1r0-009Foundation Schedule

Plan

Key

Stepped Mass trench fill with shallow reinforced concrete strip. The height of the step must notexceed the thickness of the foundation. Foundation bottoms should be horizontal and steps, asnear as possible vertical. Where services pass through trench fill foundations, they should notaffect the ability of the foundations to carry loads. Services should be either sleeved or passedthrough a suitably strengthened opening in the foundation. The foundation thickness should benot less than 500mm. Where trench fill foundations are in excess of 2.5m depth, they must bedesigned by an engineer in accordance with Technical Requirements R5, Chapter 1.1 NHBC.Excess excavation should be avoided as inaccuracy may prevent walls and piers being locatedcentrally and therefore result in eccentric loading of foundations and possible failure.Reinforcement should be clean and free form loose rust. Bars of an appropriate size should beproperly supported to ensure that they are 75mm above the base of the foundation.

Standard Strip Footings 0.90mIn accordance with NHBC Chapter 4.2

Footings 1.25m DeepFrom original ground level

In accordance with NHBC Chapter 4.2

Footings 1.50m DeepFrom original ground levelIn accordance with NHBC Chapter 4.2



Footings 2.00m DeepFrom original ground levelIn accordance with NHBC Chapter 4.2



Footings Greater Than 2.25m DeepFrom original ground level requiring specialist foundation design


Plots which require either a Stepped Mass Trench Fill Foundation, Piled Foundations or TraditionalDeep Strip Footings

Foundation Types

Plots which require Vibro Stone Ground Compaction Technique

Plots which require a Raft foundation to be designed by a structural engineer in accordance withchapter 4.5 of NHBC 2013. Raft foundations are considered suitable to mitigate against potentialinfluence of clay heave/desicration in accordance with section 4.2, sub-section D7E.

Traditional Strip Footings at 0.90m, No Identified Constraints

Depth to suitable founding strata

45024 05-08-13

1:500 @ A1

Pendle Garage,Clitheroe Road

REC Designers Residual Risk Assessment

Designers Statement of declaration

REC realises its obligations as a design organisation to avoid forseeable risks to those constructing our designs. In accordance withour statutory duties under CDM 2007, REC has taken all reasonably practicable steps to eliminate hazards, taking into accountother design considerations, from out designs.REC utilise a number of processes and documents to decide on the final design. This design risk assessment profile forms part ofthe overall REC design process and is audited as such under our ISO9001 accrediation.

Where hazards remain, then details have been provided below on the significant residual risks from those hazards. To assist otherproject team members our designer has provided information needed to identify and manage remaining significant risks for thisproject, along with justification for the final design choice.

Additional Notes

Underground Services

No allowance has been made in the foundation design to accommodate the presence or installation of underground services exceptwhere specifically noted. It is assumed that the design for the installation of underground services has or will take into account thehouse foundations as detailed on this plan and in accompanying schedule. Foundation depths should comply with BS813-1:1995.

Deep Excavations

Deep excavations will be necessary on this site. A full risk assessment and agreed method statement must be produced prior to theconstruction phase.

Trench Stability

The contractor should be aware that due to the nature of the ground conditions, it is likely that there is the potential for unstabletrenches. The contractor should allow within their tender for temporary means of support and safe methods of working. Particularreference is made to excavations immediately adjacent to existing road/footway/verge/boundary features & structures.

Construction Issues

The contractor is deemed to have considered all construction issues identified in REC drawings and should have priced for the workaccordingly.

CDM Regulations

Preparatory works such as reducing ground levels and deep excavations should be carefully considered and carried out in such amanner as to comply with the current CDM (2007) regulations, particularly for excavations close to the site boundary, existingstructures & roads.

Construction of foundations

It has been assumed at the design stage that foundations will be constructed prior to the construction of roads and the installationof drainage and services. If roads, footways or verges exist on the site prior to foundation construction, temporary support isrequired during excavation.

Underground Storage Tanks (UST's) & Fuel Lines

It will be necessary to Validate the removal of the UST's located on site and fuel lines. Once the tanks and fuel lines havesuccessfully been removed from site, Validation samples should be taken to ensure no residual contamination is present that maypose a unacceptable risk to the future site users.

Insitu Suspended Slabs

Where the depth of unsuitable material exceeds 600mm, suspended ground floor slabs are required. Reinforced insitu suspendedconcrete slabs may be used, unless influenced by vegetation (e.g Heave Zone).

New Planting

No allowance has been made for deepening of foundations due to new planting, Planting proposals to be submitted to REC forconsideration.

Saplings

Unless stated otherwise all saplings within the site and its boundary are to be removed prior to construction. For advice seekappropriate tree care specialist. Permission may be required prior to removal. Should any saplings remain then REC should beinformed prior to excavating foundations.

Geology

Ground below foundations to have a net allowable bearing pressure of 125kN/m 2 in Clay. Foundations must not be found indifferent materials as this may result in differential settlement. Foundations must not be founded in Made Ground. REC to beinformed if ground conditions differ from that anticipated. If in any doubt contact REC.

Foundation Types

For location of foundations refer to setting out and individual house and garage type layout drawings.

Max Line Loads Clay450mm wide 56600mm Wide 75

Foundations in Clay Material

Foundations in Clay material will have a minimum 900mm depth in medium volume change potential Clay and provided they areoutside the zone of influence.

Foundation Concrete

Concrete to trench fill or traiditonal strip footings to be GEN1 to BS 8500, compacted by vibration. Reinforced concrete to be RC35,compacted by vibration. Top of concrete foundations to suit construction Health & Safety requirements.

Gas/Radon Precautions

Characteristic Situation 2 / Amber 1.

Foundation Schedule

Numbers at corners of plots to be used when referring to foundation schedule.

Step Up Detail Minimum Depth Requirement forFoundations

1

2

3

4

Back

Front

Bowsall Ltd.


APPENIDIX IV

PHOTOGRAPHS

AP

PE

ND

IX IV

P

HO

TO

GR

AP

HS


PLATE 1 – LOOKING TOWARDS EASTERN BOUNDARY OF SITE

PLATE 2 – LOOKING WEST ACROSS THE SITE


PLATE 3 – LOOKING ONTO FIELD BOUNDARY INTO AREA OF SITE WHERE ACCESS WAS RESTIRCTED

PLATE 4 – MOTOR INSPECTION RAMP


PLATE 5 – VENTILATION PIPES

PLATE 6 – TYPICAL FLOODING OF TANK FILLING POINT


PLATE 7 – TYPICAL GROUND CONDITIONS WITHIN TRIAL PIT IN WESTERN SECTOR

PLATE 8 – TYPICAL GROUND CONDITIONS IN EASTERN SECTOR OF SITE


APPENDIX V

REC EXPLORATOTY HOLE LOGS

AP

PE

ND

IX V

E

XP

LO

RA

TO

RT

LO

GS

Trial Pit Number:Project Number:

Contract Name:

Client:

Engineer:

Date Started:

Date Completed:

Elevation AOD (m):

Co-ordinates:

Excavation Method:

Dimensions:

Services:

Stability:

Groundwater:

Date:

Status:

SUBSURFACE PROFILE SAMPLES AND IN-SITU TESTING

Depth

(m

bgl)

1.0

2.0

3.0

4.0

5.0

6.0

Legend

DescriptionDepth ofStrata(mbgl)

TypeDepth(mbgl)

WaterLevel(mbgl)

P.I.D(ppm) Field /

LaboratoryTesting

Osprey HousePacific QuayBroadwayManchester, M50 2UETel: 0161 868 1300 / Fax: 0161 868 1301www.recltd.co.uk

Key B. Bulk (Bag) W. WaterU100. 100mm UndisturbedU38. 38mm Undisturbed SampleSPT. Standard Penetration Test

D. DisturbedG. Amber Glass Jar / BottleCPT. Cone Penetration TestU100. Blows (Recovery mm)V. 40ml Glass Vial

T. Plastic TubN. 'N' ValueHV. Hand Shear VanePID. Photo Ionisation DetectorES. Environmental Sample

Notes

Trial Pit Record

Prior to excavation the trial pit location was scanned with a Cable Avoidance Tool (CAT).

TP10145024

Pendle Garage

Bowsall Ltd

B. Gichanga

27/06/13

27/06/13

N/A

N/A

JCB 3CX

MADE GROUND: Brown grey clayey gravel with occasional fragments of metal. Gravel is medium to coarse angular to sub-angular with frequent cobbles of brick, concrete and limestone.

MADE GROUND : Firm dark brown ashy sandy clay.

Firm to stiff brown grey gravelly sandy CLAY. Gravel is medium to coarse angular to sub-angular with frequent cobbles of brick, concrete and limestone.

Becoming very gravelly at 2.40m bgl.

Terminated at 2.90m bgl.

0.50

0.90

2.90

ES

ES

ES

T

HSV

0.10

0.70

1.50

1.50-2.00

1.50-2.00

25 50 750 100

93kPa/37kPa

Stable

None encountered

18/07/13

Final


Contract Name:

Client:

Engineer:

Date Started:

Date Completed:

Elevation AOD (m):

Co-ordinates:

Excavation Method:

Dimensions:

Services:

Stability:

Groundwater:

Date:

Status:


Depth

(m

bgl)

1.0

2.0

3.0

4.0

5.0

6.0

Legend


TypeDepth(mbgl)

WaterLevel(mbgl)

P.I.D(ppm) Field /

LaboratoryTesting





Notes

Trial Pit Record


TP10245024

Pendle Garage

Bowsall Ltd

B. Gichanga

27/06/13

27/06/13

N/A

N/A

JCB 3CX

MADE GROUND: Dark brown black gravel with fragments of metal. Gravel is medium to coarse angular to sub-angular of concrete, brick and limestone. Possible asbestos containing material.

MADE GROUND: Firm dark brown ashy gravelly CLAY. Gravel is medium to coarse angular to sub-angular.

Stiff brown grey gravelly sandy CLAY. Gravel is medium to coarse angular to rounded of sandstone, siltstone and mudstone.

Becoming very gravelly at 2.50m bgl.


0.50

0.80

2.80

ES

ES

T

HSV

0.30

1.00

1.00-1.50

1.00-1.50

25 50 750 100

120kPa

Stable

None encountered

18/07/13

Final


Contract Name:

Client:

Engineer:

Date Started:

Date Completed:

Elevation AOD (m):

Co-ordinates:

Excavation Method:

Dimensions:

Services:

Stability:

Groundwater:

Date:

Status:


Depth

(m

bgl)

1.0

2.0

3.0

4.0

5.0

6.0

Legend


TypeDepth(mbgl)

WaterLevel(mbgl)

P.I.D(ppm) Field /

LaboratoryTesting





Notes

Trial Pit Record


TP10345024

Pendle Garage

Bowsall Ltd

B. Gichanga

27/06/13

27/06/13

N/A

N/A

JCB 3CX

MADE GROUND: Dark brown clayey gravel. Gravel is medium to coarse angular to sub-angular of brick, concrete and limestone.

MADE GROUND : Firm dark brown ashy gravelly CLAY. Gravel is medium to coarse angular to sub-angular of sandstone and siltstone.

Firm to stiff brown grey gravelly CLAY.


0.85

1.10

3.00

ES

ES

ES

HSV

0.20

0.90

1.50

1.50-2.00

25 50 750 100

120kPa

Stable

None encountered

18/07/13

Final


Contract Name:

Client:

Engineer:

Date Started:

Date Completed:

Elevation AOD (m):

Co-ordinates:

Excavation Method:

Dimensions:

Services:

Stability:

Groundwater:

Date:

Status:


Depth

(m

bgl)

1.0

2.0

3.0

4.0

5.0

6.0

Legend


TypeDepth(mbgl)

WaterLevel(mbgl)

P.I.D(ppm) Field /

LaboratoryTesting





Notes

Trial Pit Record


TP10445024

Pendle Garage

Bowsall Ltd

B. Gichanga

27/06/13

27/06/13

N/A

N/A

JCB 3CX

MADE GROUND: Dark brown clayey gravel. Gravel is medium to coarse angular to sub-angular with occasional cobbles of concrete, brick and limestone.

MADE GROUND : Firm dark brown ashy gravelly sandsy clay. Gravel is medium to coarse angular to sub-angular of sandstone and siltstone.

Firm to stiff brown grey gravelly sandy CLAY. Gravel is medium to coarse angular to rounded of sandstone and siltstone.


0.40

0.80

2.90

ES

ES

HSV

0.40

1.00

1.00-1.50

25 50 750 100

120kPa

Stable

None encountered

18/07/13

Final


Contract Name:

Client:

Engineer:

Date Started:

Date Completed:

Elevation AOD (m):

Co-ordinates:

Excavation Method:

Dimensions:

Services:

Stability:

Groundwater:

Date:

Status:


Depth

(m

bgl)

1.0

2.0

3.0

4.0

5.0

6.0

Legend


TypeDepth(mbgl)

WaterLevel(mbgl)

P.I.D(ppm) Field /

LaboratoryTesting





Notes

Trial Pit Record


TP10545024

Pendle Garage

Bowsall Ltd

B. Gichanga

27/06/13

27/06/13

N/A

N/A

JCB 3CX

MADE GROUND: Dark brown clayey gravel. Gravel is medium to coarse angular to sub-angular with occasional cobbles of concrete, brick and limestone.

MADE GROUND: Firm dark brown ashy gravelly sandy clay. Gravel is medium to coarse angular to sub-angular of sandstone and siltstone.

Firm to stiff brown gravelly CLAY.


0.40

0.70

2.90

ES

ES

ES

HSV

0.10

0.50

1.20

1.50-2.00

25 50 750 100

120kPa

Stable

None encountered

18/07/13

Final


Contract Name:

Client:

Engineer:

Date Started:

Date Completed:

Elevation AOD (m):

Co-ordinates:

Excavation Method:

Dimensions:

Services:

Stability:

Groundwater:

Date:

Status:


Depth

(m

bgl)

1.0

2.0

3.0

4.0

5.0

6.0

Legend


TypeDepth(mbgl)

WaterLevel(mbgl)

P.I.D(ppm) Field /

LaboratoryTesting





Notes

Trial Pit Record


TP10645024

Pendle Garage

Bowsall Ltd

B. Gichanga

27/06/13

27/06/13

N/A

N/A

JCB 3CX

MADE GROUND: Dark brown clayey gravel. Gravel is medium to coarse ang

Documents

PHASE II GEO-ENVIRONMENTAL SITE INVESTIGATION Clitheroe … · 2014. 8. 14. · Geo-Environmental Investigation August 2013 Former Pendle Garage 45024p1r0 Page 3 of 33 EXECUTIVE SUMMARY