Safeguarding your business environment · 2017-02-14 · 3. ANTICIPATED GROUND CONDITIONS 3.1 Published Geology 3.1.1 General Characteristics The published 1:50,000 scale geological

Kier Marriott

BSF Kettering Science Academy

Geotechnical Report

251076

January 2010

Safeguarding your business

environment

Report No. 251076-01 BSF Kettering Science Academy Page 2 of 20

CONTENTS DOCUMENT CONTROL 3

1. INTRODUCTION ............................................................................................................................. 4 1.1 Instructions........................................................................................................................... 4 1.2 Project Brief .......................................................................................................................... 4 1.3 Limitations ............................................................................................................................ 4

2. SITE DETAILS................................................................................................................................. 5 2.1 Description and Geographic Setting.................................................................................. 5

3. ANTICIPATED GROUND CONDITIONS........................................................................................ 6 3.1 Published Geology............................................................................................................... 6

4. GROUND INVESTIGATION............................................................................................................ 7 4.1 Site Work............................................................................................................................... 7

5. PHYSICAL GROUND CONDITIONS.............................................................................................. 8 5.1 Findings of Ground Investigation ...................................................................................... 8 5.2 Groundwater....................................................................................................................... 12

6. ENGINEERING CONSIDERATIONS............................................................................................ 13 6.1 Details of the Proposed Development ............................................................................. 13 6.2 Geotechnical Hazards........................................................................................................ 13 6.3 Foundations........................................................................................................................ 15 6.4 Ground Floor Slabs............................................................................................................ 18 6.5 Chemical Attack on Buried Concrete............................................................................... 18

7. CONCLUSIONS AND RECOMMENDATIONS............................................................................. 19 7.1 Conclusions........................................................................................................................ 19 7.2 Recommendations for Further Geotechnical Work........................................................ 20

FIGURES

Figure 1 Site Location Plan

Figure 2 Site Layout & Exploratory Point Location Plan

Figure 3 Geological Cross Section A

Figure 4 Geological Cross Section B

Figure 5 SPT Plot versus Depth

APPENDICES

Appendix A Fieldwork Records

Window Sampler Records

Dynamic Probe Records

RSK STATS Geoconsult Ltd The Enterprise Centre

Coventry University Technology Park

Puma Way

Coventry

CV1 2TX

UK

Telephone: +44 (0)2476 236816

Fax: +44 (0)2476 236014

www.rsk.co.uk

RSK STATS Geoconsult Ltd

Registered office

Spring Lodge • 172 Chester Road • Helsby • Cheshire • WA 0AR • UK

Registered in England No. 2611785

www.rsk.co.uk

DOCUMENT CONTROL

Document Title: Geotechnical Report


The Client: Kier Marriott Marriott House Brindley Close Rushden Northamptonshire NN10 6EN

RSK STATS Geoconsult Ltd (RSK) has prepared this report in accordance with the instructions of BDP Limited, acting on behalf of Kier Marriott (“the Client”) by e-mail, dated 17

th December 2009

and under the terms of appointment for RSK. This report is confidential and non-assignable by the Client and RSK shall not be responsible for any use of the report or its contents for any purpose other than that for which it was prepared and provided. Should the Client require to pass copies of the report to other parties for information, the whole of the report should be so copied, but no professional liability or warranty shall be extended to other parties by RSK in this connection without the explicit written agreement thereto by RSK.

Report Number

251076-01

Status

FINAL

Date of issue

19th January 2010

Prepared by Mariah Gray

Graduate Geoenvironmental Engineer

Reviewed by Mark Steward

Associate Director

Approved by Shon Williams

Director

Page no. 3 of 20


1. INTRODUCTION

1.1 Instructions

On the instructions of BDP Limited, on behalf of Kier Marriott (the ‘Client’), RSK STATS

Geoconsult Ltd (RSK) has carried out a Supplementary Geotechnical Investigation of the

playing fields at the Kettering Science Academy, to the south of Deeble Road, Kettering.

The project was commissioned in order to confirm ground conditions at the site, and thence to

assess the foundation options for the proposed development: a two-storey educational

building with a footprint of approximately 9000m2.

1.2 Project Brief

The project was carried out to an agreed brief as set out in RSK’s proposal letter of 11th

December 2009.

The work undertaken included the following tasks:

• A site walk-over reconnaissance survey;

• A study of the local geology of the site;

• A review of the information in Geotechnics’ Factual Report PC093889;

• Sinking of eight drive-in window sampler boreholes, to depths of 4.0m.bgl;

• Sinking of five dynamic probe holes, to depths of 5.0m.bgl;

• Associated soil sampling and in-situ testing; and

• Interpretative reporting.

The intrusive aspects of the investigation were generally carried out following guidance given

in BS 5930:1999.

1.3 Limitations

This report should be considered in the light of any changes in legislation, statutory

requirement or industry practices that may have occurred subsequent to the date of issue.

The "vicinity" of the site for the purposes of this report, is defined as locations situated within

an approximate 250m radius of the site.

The opinions and recommendations expressed in this report are based on the ground

conditions encountered during the site work, the results of field testing and interpretation

between exploratory holes. The material encountered and samples obtained represent only a

small proportion of the materials present on-site, therefore other conditions may prevail at the

site which have not been revealed by this investigation.

The accuracy of the information provided by Geotechnics through their exploratory hole logs,

geotechnical laboratory testing results and final report cannot be guaranteed, and RSK cannot

be held liable for any issues resulting from reliance on these data.

Geotechnical laboratory testing and the investigation of issues relating to ground

contamination were outside the agreed scope of works.


2. SITE DETAILS

2.1 Description and Geographic Setting

The site is located approximately 1.2km to the east of Kettering, at National Grid reference SP

879 784, as shown in Figure 1.

The site covers approximately 3.2 hectares and comprises the two playing fields to the east of

Ise Community College, as shown in Figure 2. The playing fields are on two levels; the

western playing field is several metres higher than the eastern field, and they are separated

by a fairly steep slope approximately 2.5m high.

The area around the site is generally residential, with small areas of undeveloped floodplain

associated with the River Ise, which flows in a southerly direction approximately 80m to the

east of the site boundary.


3. ANTICIPATED GROUND CONDITIONS

3.1 Published Geology

3.1.1 General Characteristics

The published 1:50,000 scale geological map of the area (Sheet 171, ‘Kettering’) indicates

that the site is underlain by deposits of Whitby Mudstone Formation, with a small area of

Alluvium along the eastern edge of the site, associated with the River Ise. The area covered

by the Kettering Science Academy buildings, adjacent to the west of the site, is underlain by

the Northampton Sand Formation, which is further underlain by the Whitby Mudstone

Formation.

On the basis of the published geological maps of the area, the full succession of natural strata

in the vicinity of the site is likely to comprise:

Table 3.1 Conjectural Geological Succession Beneath the Site

Geological Unit Brief Description Anticipated

Thickness

Superficial Soils/Drift

Alluvium Silty clay, possibly containing layers of silt, peat

and gravel

Several

metres

Solid Geology Deposits

Northampton Sand

Formation

Greenish grey sandy ironstone, weathering to

brown limonitic sandstone, and generally becoming

less iron-rich and more clayey at its base

4 – 8m

(max. 21m)

Whitby Mudstone

Formation

Dark grey fossiliferous mudstone and siltstone,

occasionally with thin siltstone, silty mudstone and

calcareous sandstone beds

Up to 120m

The former topography and subsequent re-grading of the site suggests that, in addition to

these natural strata, made ground is likely to be present beneath the site, especially in the

area of the embankment between the upper and lower playing fields.

Details of a previous ground investigation carried out by Geotechnics Limited (Factual Report

PC093889, June 2009) were provided by Andrew Tatlock of Kier Marriott. Information from

the report is summarised in Section 5.


4. GROUND INVESTIGATION

4.1 Site Work

4.1.1 Rationale

The purpose of the intrusive investigation is to provide geotechnical information in the locality

of the proposed development. The techniques adopted for the investigation have been

chosen considering the anticipated ground conditions and the proposed development.

4.1.2 Scope of Works

The site work was carried out on 21st and 22

nd December 2009, and comprised the sinking of

eight drive-in window sampler boreholes to depths of 4.0m.bgl and five dynamic probe holes

to depths of 5.0m.bgl. The investigation and the soil descriptions were carried out in general

accordance with BS5930:1999 - Code of Practice for Site Investigations.

The exploratory hole logs and other site work records are presented in Appendix A.

The investigation points were marked out by a Kier engineer at the time of investigation. The

ground levels at the borehole locations were interpolated from the levels shown on the site

plan provided by Randall Surveys LLP.

4.1.3 Limitations of Fieldwork

Due to the covering of snow, it was not possible to locate the holes accurately on the site

plan, although they were kept outside the sports pitches. Their approximate positions are

shown on Figure 2.


5. PHYSICAL GROUND CONDITIONS

5.1 Findings of Ground Investigation

5.1.1 General Succession of Strata

The exploratory holes revealed that the site is underlain by a variable thickness of Made

Ground over the Northampton Sand Formation, with the Whitby Mudstone Formation at

depth. The central section of the site, comprising the embankment between the two playing

fields, contains an area of Fill between the Made Ground and the Northampton Sand

Formation. The eastern edge of the site is underlain by Made Ground over Alluvium, which is

then underlain by the Whitby Mudstone Formation at depth. This appears to generally

confirm the stratigraphical succession described within Section 3.1.

For the purpose of discussion, the ground conditions are summarised in Table 5.1, below,

and are presented as two geological cross-sections (A and B) as Figures 3 and 4. Cross-

Section A contains WS1, WS5, WS6 and WS7, while Cross-Section B contains WS2, WS3,

WS4 and WS8. All the tables in this section also include any relevant data from Geotechnics’

Report PC093889, thereby summarising all the data from the area of the two playing fields.

Throughout the remainder of this report, the Geotechnics’ exploratory holes are prefixed with

“G”, in order to distinguish them from RSK exploratory hole designations.

Table 5.1 General Succession of Strata Encountered

Stratum Exploratory Holes

Encountered

Depth to top

of stratum

m.bgl

Depth to base

of stratum

m.bgl

Thickness

(m)

Made Ground All 0.00 0.20 – 1.40 0.20 – 1.40

Fill WS4, WS5 & GBH24 0.35 – 0.90 1.30 – 3.50 0.90 – 2.60

Alluvium WS7, WS8,

GWS26 & GWS27 0.40 – 1.40 2.45 – >5.00 2.05 – >3.60

Northampton Sand

Formation

All except

WS7, WS8, GWS26,

GWS27& GBH24

0.20 – 3.50 0.70 – >4.00 0.20 – 3.25

Whitby Mudstone

Formation

All except

WS4, WS8 & GWS27 0.70 – >5.00 >10.00 >7.20

5.1.2 Made Ground

The exploratory holes encountered a variable thickness of Made Ground across the site,

generally ranging from 0.20m to 1.00m. The variation in the thickness of the Made Ground

across the site does not appear to correspond to any particular features, with the exception of

the 1.40m of Made Ground encountered within GWS27, the closest exploratory hole to the

River Ise.

In general the Made Ground encountered during RSK’s investigation comprised firm to stiff

slightly silty slightly gravelly occasionally slightly sandy CLAY, with rare rootlets and minor

constituents including sandstone and brick cobbles, and tin, clinker, ash, slag and brick

fragments.

Visual / olfactory evidence of contamination, other than the minor constituents noted above,

was not encountered within the Made Ground.


The measured and inferred soil parameters for the Made Ground are listed in Table 5.2,

below.

Table 5.2 Summary of Soil Parameters for the Made Ground

Soil Parameters Range Results

Consistency Term Firm – Stiff Appendix A

Soil Suction (kN/m2) 25 – 105 Appendix A

Strength Term Low – High

5.1.3 Fill

The exploratory holes WS4 and WS5, located at the top of the embankment between the two

playing fields, generally encountered between 2.45m and 2.60m of Fill, underlying the Made

Ground. GBH23, located at the far northerly end of the slope between the two playing fields,

and possibly slightly on the embankment up to Deeble Road, only encountered 0.90m of Fill.

In general the Fill encountered during RSK’s investigation comprised three main layers. The

first contained firm to stiff slightly silty slightly gravelly CLAY with rare decayed rootlets. The

gravel was angular to subrounded fine to medium occasionally coarse ferruginous sandstone.

The second layer contained firm to stiff slightly silty slightly sandy slightly gravelly CLAY, with

occasional ferruginous sandstone cobbles and rare fine to medium gravel sized clinker

fragments within WS4. The gravel was subangular to subrounded fine to medium flint. The

base of this layer was mottled black, with a high organic / decayed plant fragment / wood

content.

The third layer contained firm to stiff slightly silty slightly sandy CLAY. The sand was fine to

medium.

With the exception of the clinker fragments within WS4, visual / olfactory evidence of

contamination was not encountered within the Fill.

As shown in Figure 5, the Fill increases in strength with depth.

The measured and inferred soil parameters for the Fill are listed in Table 5.3, below.

Table 5.3 Summary of Soil Parameters for the Fill


Moisture Content (%) 26 – 27 Geotechnics Report

SPT ‘N’ Values 5 – 13 Figure 5 (labelled as Made Ground)

Undrained Shear Strength (kN/m2)

inferred from SPT ‘N’ values 25 – 65

Consistency Term Firm – Stiff Appendix A


Strength Term Medium – High


5.1.4 Alluvium

The Alluvium, encountered at the eastern end of the lower playing field during RSK’s

investigation, within WS7 and WS8, comprised three main layers. The first contained stiff

slightly gravelly CLAY. The gravel was subangular to subrounded fine ferruginous sandstone

and flint.

The second layer contained slightly sandy, gravelly to very gravelly CLAY. The sand was fine

to coarse, and the gravel was angular to rounded fine to medium flint.

The third layer contained medium dense clayey very sandy angular to rounded fine to coarse

flint GRAVEL. The sand was fine to coarse.

Within WS8, a layer of stiff slightly silty slightly gravelly CLAY was encountered between the

second and third layers. Within WS7, a layer of medium dense clayey very gravelly fine to

coarse SAND was encountered beneath the third layer.

Visual / olfactory evidence of contamination was not encountered within the Alluvium.

As shown in Figure 5, the Alluvium generally increases in strength with depth.

The measured and inferred soil parameters for the Alluvium are listed in Table 5.4, below.

Table 5.4 Summary of Soil Parameters for the Alluvium



SPT ‘N’ Values 5 – 18 Figure 5



Consistency Term (cohesive) Stiff Appendix A

Consistency Term (granular) Medium Dense Appendix A

Soil Suction (kN/m2) 90 Appendix A

Strength Term High

5.1.5 Northampton Sand Formation

The Northampton Sand Formation, encountered during RSK’s investigation below the Made

Ground across the site with the exception of WS7 and WS8, typically comprised firm to stiff

CLAY with varying proportions of silt, sand and gravel, and with rare decayed rootlets and

occasional iron-rich laminations. The granular layers within this formation were generally

loose. This stratum is sometimes termed “Superficial Deposits” within the Geotechnics

Report.

Visual / olfactory evidence of contamination was not encountered within the Northampton

Sand Formation.

As shown in Figure 5, the Northampton Sand Formation increases in strength with depth.

The measured and inferred soil parameters for the Northampton Sand Formation are listed in

Table 5.5, below.


Table 5.5 Summary of Soil Parameters for the Northampton Sand Formation


Liquid Limit (%) 51 Geotechnics Report

Plastic Limit (%) 26 Geotechnics Report

Plastic Index (%) 25 Geotechnics Report

Modified Plasticity Index (%) 25

Plasticity Term High (CH)

Volume Change Potential (NHBC) Medium





Consistency Term (cohesive) Firm – Stiff Appendix A

Consistency Term (granular) Loose Appendix A


Strength Term Medium – High

5.1.6 Whitby Mudstone Formation

The Whitby Mudstone Formation encountered during RSK’s investigation, and underlying the

Northampton Sand Formation or Alluvium in the former’s absence, typically comprised stiff to

very stiff occasionally firm silty CLAY, with selenite present. This stratum was formerly named

the Upper Lias Clay, the term used in the Geotechnics Report.

Visual / olfactory evidence of contamination was not encountered within the Whitby Mudstone

Formation.

As shown in Figure 5, the Whitby Mudstone Formation generally increases in strength with

depth.

The measured and inferred soil parameters for the stratum are listed in Table 5.6, below.

Table 5.6 Summary of Soil Parameters for the Whitby Mudstone Formation


Liquid Limit (%) 50 – 56 Geotechnics Report

Plastic Limit (%) 24 – 27 Geotechnics Report

Plastic Index (%) 26 – 29 Geotechnics Report

Modified Plasticity Index (%) 26 – 29

Plasticity Term High (CH)

Volume Change Potential (NHBC) Medium




measured by Triaxial Testing 61 – 64 Geotechnics Report





Consistency Term Soft/Firm – Stiff

Very Stiff (Geotechnics data) Appendix A


Strength Term High – Very High

5.2 Groundwater

Groundwater was encountered within the majority of RSK’s exploratory holes at the depths

summarised in Table 5.7; from anecdotal evidence, the playing fields are known to be

frequently waterlogged.

Table 5.7 Groundwater Results

WS Stratum Strike

m.bgl

Rise

m.bgl

WS1 Made Ground 0.30 (seepage) Unknown

WS2 Northampton Sand Formation 0.50 (seepage) Unknown

WS5 Made Ground / Fill 0.30 (seepage) 0.90

WS6 Northampton Sand Formation Not visible 1.00

WS7 Alluvium Not visible 0.85

WS8 Made Ground Not visible 0.80

GWS21 Northampton Sand Formation 3.00 (damp) Unknown

GWS27 Made Ground 1.00 (seepage) Unknown

It should be noted that groundwater levels might fluctuate for a number of reasons, including

seasonal variations. On-going monitoring would be required to establish both the full range of

conditions and any trends in groundwater levels.


6. ENGINEERING CONSIDERATIONS

6.1 Details of the Proposed Development

It is understood that the proposed development will comprise a two-storey reinforced concrete

frame educational building with a footprint of approximately 9000m2. The site will be levelled

by a cut-and-fill exercise to achieve finished floor levels of 67.0m.AOD for the ground floor

and a 65.5m.AOD for the lower ground floor. Information provided by BDP Limited indicates

that the maximal column loads will be in the order of 1500kN on an approximate 7.5m grid

spacing.

6.2 Geotechnical Hazards

A summary of commonly occurring geotechnical hazards is given in Table 6.1 together with

an assessment of whether the site may be affected by each of the stated hazards.

Table 6.1 Summary of Main Potential Geotechnical Hazards that May Affect Site

Hazard category

(excluding contamination

issues)

Hazard status

based on investigation findings

and proposed development

Engineering

considerations

if hazard affects site

Found to

be

present

on site

Could be

present but

not found

Unlikely to

be present

and/or affect

site

Sudden lateral changes in

ground conditions 4

Alluvium, associated with

the River Ise, is present

only along the eastern side

of the lower playing field

Likely to affect ground

engineering and

foundation design and

construction

Shrinkable clay soils

4

The Northampton Sand

and Whitby Mudstone

Formations comprise clay

of medium volume change

potential

Design to NHBC

Standards Chapter 4

or similar

Highly compressible and low

bearing capacity soils,

(including peat and soft clay) 4


engineering and


construction

Silt-rich soils susceptible to

loss of strength in wet

conditions 4

Variable silt content in the

Northampton Sand and

Whitby Mudstone

Formations


engineering and


construction

Karstic dissolution features

(including ‘swallow holes’ in

Chalk terrain) 4

May affect ground

engineering and


construction


Hazard category


issues)

Hazard status



Engineering

considerations


Found to

be

present

on site

Could be

present but

not found

Unlikely to

be present

and/or affect

site

Evaporite dissolution

features and/or subsidence 4

May affect ground

engineering and


construction

Ground subject to or at risk

from landslides 4

Likely to require

special stabilisation

measures

Ground subject to peri-glacial

valley cambering with gulls

possibly present 4


engineering and


construction

Ground subject to or at risk

from coastal or river erosion 4

Likely to require

special

protection/stabilisation

measures

High groundwater table

(including waterlogged

ground) 4

Groundwater encountered at shallow depths beneath the site. From anecdotal

evidence, the playing fields are known to be frequently waterlogged

May affect temporary

and permanent works

Rising groundwater table due

to diminishing abstraction in

urban area 4

May affect deep

foundations,

basements and

tunnels

Underground mining

4

Likely to require

special stabilisation

measures

Existing sub-structures (e.g.

tunnels, foundations,

basements, and adjacent

sub-structures)

4


engineering and


construction

Filled and made ground

(including embankments,

infilled ponds and quarries)

4

A variably thick layer of

Made Ground covers the

entire site. Greater

thickness of Made Ground

and Fill is present within

the slope separating the

upper and lower playing

fields


engineering and


construction


Hazard category


issues)

Hazard status



Engineering

considerations


Found to

be

present

on site

Could be

present but

not found

Unlikely to

be present

and/or affect

site

Adverse ground chemistry

(including expansive slags

and weathering of sulphides

to sulfates)

4 See

Section 6.5

May affect ground

engineering and


construction

Note: Seismicity is not included in the above table, as this is not normally a design consideration in the

UK.

6.3 Foundations

6.3.1 General Suitability

The ground conditions at the western end of the upper field appear suitable for the design and

construction of relatively shallow spread foundations for lightly loaded structures. However, in

view of the anticipated high loads from the proposed development (1500kN) and the

increasing thickness of the Made Ground and Fill towards the eastern end of the upper field

and the embankment, foundations will have to be taken to a greater depth. Deep spread

foundations appear technically feasible, although the depth to which such foundations will

need to extend may mean that piles will provide a more economic foundation solution.

Alternatively, the near-surface ground conditions appear suitable for the use of selected

ground improvement techniques that would facilitate the use of shallow spread footings

supported on the improved ground.

6.3.2 Spread Foundations

The recommendations for the design and construction of spread foundations in relation to the

ground conditions are set out in Table 6.2.

Table 6.2 Design and Construction of Spread Foundations

Design/construction

considerations

Design/construction recommendations

Founding stratum Northampton Sand Formation or Whitby Mudstone Formation

Depth Foundations should be taken to a minimum depth of 1.5m below

finished ground level (around 64.0m.AOD) and at least 0.1m into the

founding stratum below any overlying Made Ground, or to any greater

depth required in respect of the special design considerations given

below.

Special design

considerations

Due to the presence of shrinkable soils, foundations should be designed

taking into account all the normal precautions, including minimum

depths, to minimise the risk of future foundation movements in

accordance with NHBC Standards, or similar.

The findings of the ground investigation indicate that foundations should

be designed for shrinkable soils of medium volume change potential.

During all cut-and-fill exercises, especially involving slopes near the

River Ise, the stability of the slopes created should be considered; the


Design/construction

considerations


maximum gradient recommended is 1:3.

It is noted that the areas of the site underlain by the Northampton Sand

Formation are within an area for which full radon protection measures

are required. Further advice may be obtained from the Documents of

the National Radiological Protection Board (Radon Atlas of England and

Wales, NRPB-W26-2002), and further assessment will be required, in

line with the guidance provided in BRE publication 211 “Radon:

guidance on protective measures for new dwellings (2007)

Bearing capacity Strip foundations with a width of up to 2.00m, or pad foundations with a

width of up to 4.00m, both constructed on the Northampton Sand

Formation or Whitby Mudstone Formation at a minimum depth of 1.5m

may be designed using a net allowable bearing pressure of 100kN/m2.

The allowable bearing capacity includes an overall factor of safety of 3

against bearing capacity failure and with total settlements associated

with the bearing pressure estimated to be less than 25mm.

Dewatering Groundwater was encountered in the majority of the exploratory holes.

Dewatering may therefore be required to facilitate foundation

excavation.

The cohesive nature of the soils encountered suggests that pumping

from open sumps should be sufficient to keep the excavations

reasonably dry

Stability of

excavations

Due to the potential for the high groundwater level to affect the stability

of excavations, it is recommended that excavation support systems are

made available during the groundwork stage of the development

Construction

considerations

All foundation excavations should be inspected and any made ground,

soft, organic or otherwise unsuitable materials removed and replaced

with mass concrete

6.3.3 Piled Foundations

The recommendations for the design and construction of piled foundations in relation to the

ground conditions are set out in Table 6.3. It should be noted that the soil parameters used

for the design are adopted from deeper boreholes undertaken by Geotechnics, although the

final depths to which those boreholes are taken may not be sufficient to provide the necessary

information for the design.

Table 6.3 Design and Construction of Piled Foundations

Design/construction

considerations


Pile type The construction of both bored and driven piles is considered technically

feasible at this site

Possible constraints

on choice of pile type

Given the close proximity of the site to other properties the use of driven

piles may not be acceptable due to ground vibration and noise related

problems

Temporary casing

where groundwater is

present

Bored piles may require temporary casing throughout their depth due to

the possible presence of groundwater within the Whitby Mudstone

Formation. Alternatively, the use of continuous-flight-auger (CFA)

injected bored piles usually overcomes this issue


Design/construction

considerations


Man-made

obstructions

The presence of buried sub-structures or other obstructions within Made

Ground may lead to some difficulty during piling. It is recommended

that once the proposed pile layout has been determined, pre-pile

probing be carried out at each of the pile positions. Where buried

obstructions are encountered, it will be necessary to either relocate the

pile(s) or make allowance for removing the obstruction

Hard strata An allowance should be made for chiselling thin ‘rock’ bands (claystone)

within the Whitby Mudstone Formation

Adhesion Factor (α) 0.5

Bearing Capacity Factor (Nc) 9

Undrained Shear Strength (cu) 80 + 7z kN/m2 where z = depth into

clay

Global Safety Factor 3.0

Limiting Shaft Friction 140kN/m2

Soil and pile design

parameters for Whitby

Mudstone Formation

Limiting Concrete Stress 7.5N/mm2

Bored pile shafts and

bases

Bored pile concrete should be cast as soon after the completion of

boring as possible and in any event the same day as boring.

Prior to casting, the base of the pile bore should be clean, otherwise a

reduced safe working load will be required. Similarly, if the pile bore is

left open, the shaft walls may relax/soften, leading to a reduced safe

working load.

The design procedure for piles varies considerably, depending on the proposed type of pile.

However, for illustrative purposes Table 6.4 gives likely working pile loads for traditional

bored, cast-in-situ concrete piles of various diameters and lengths, based on the design

parameters given in Table 6.3.

Table 6.4 Illustration of Typical Pile Working Loads for Bored Cast-in-situ Piles

Typical Pile Working Loads (kN)

Pile Diameter Depth of pile below

existing ground

level (m) 300mm 450mm 600mm 750mm

10 165 268 387 520

151)

293 466 658 867

201)

448 705 983 1284

251)

530 985 1364 1769

1) assumed Whitby Mudstone Formation extents at depth

6.3.4 Vibro-replacement

As discussed in Section 6.3.1, should it not be possible to remove sufficient soil to penetrate

the base of the Made Ground or Fill, consideration can be given to improving the soil using

some form of ground improvement such as vibro replacement. Advice regarding the specific

design of the columns should be sought from a specialist contractor.


The impact of the vibro-stone columns on any slopes remaining on site should be assessed,

in order that they do not affect the slopes’ stability.

6.3.5 Eastern Playing Field

The ground conditions on the eastern (lower) playing field generally comprise materials with

average undrained shear strengths of 50kN/m2, equating to bearing capacities of approximately

100kN/m2. It is considered that the ground will be able to support a build up of the proposed fill

in relation to the building up of the field to accommodate the proposed surface water drainage

attenuation tanks. It is however recommended that the formation levels are inspected and any

made ground, soft, organic or otherwise unsuitable materials removed and replaced with

mass concrete.

6.4 Ground Floor Slabs

The sub-grade soil conditions beneath the footprint of the proposed buildings comprise a

variable thickness of Made Ground and Fill over Northampton Sand Formation over Whitby

Mudstone Formation. Ground bearing floor slabs could be adopted with a suitable sub-base

layer for the proposed development. The proposed ‘levelling’ of the site by cut-and-fill

technique means that at some point the ground bearing slabs will pass from natural ground on

to structural fill, resulting in differential settlements from the floor slab loading due to the

difference in the stiffness of the two materials. To achieve a comparable stiffness between

natural ground and compacted fill, some form of treatment of the latter may be required. In

addition, where a slab crosses over the junction from natural ground to compacted fill it is

recommended that the slab is suitably reinforced to accommodate possible movements and a

transition zone consisting of a stabilised layer of the natural sub-grade material should also be

introduced.

6.5 Chemical Attack on Buried Concrete

The results of chemical tests carried out on soil samples from the entire Kettering Science

Academy Site as part of Geotechnics’ investigation indicate 2:1 water soil extract sulfate

contents of up to 0.96g/l with pH values ranging between 5.2 and 7.3.

These results indicate that, in accordance with BRE Special Digest 1: 2005 Concrete in

aggressive ground, the Aggressive Chemical Environment for Concrete (ACEC) Classification

is AC-2 with a Design Sulfate Class for the site of DS-2. This assumes nominally mobile

groundwater conditions, and that no significantly disturbed clay comes into contact with

concrete foundations or structures. However, it is noted that a pH of 5.2 was recorded in

GWS19, which would indicate an ACEC classification of AC-4z. However, as this low pH was

detected in only one of the 13 samples tested, and the average pH of the samples tested from

the site is 6.7, it is considered that this result can be discounted.

If significantly disturbed clay is likely to come into contact with concrete foundations or

structures, it will be necessary to carry out additional tests on the soil to investigate its total

potential sulfate content. This will facilitate a re-evaluation of the ACEC Classification and

Design Sulfate Class for the material, to take into consideration potential oxidation of available

sulphides (e.g. pyrite), as defined in Table C1 (natural ground sites) or C2 (brownfield sites)

BRE Special Digest 1: 2005.


7. CONCLUSIONS AND RECOMMENDATIONS

7.1 Conclusions

The site covers approximately 3.2 hectares, and currently comprises the two playing fields to

the east of Ise Community College. The currently proposed development is understood to

comprise a two-storey educational building with a footprint of approximately 9000m2.

Information provided by BDP Limited indicates that the maximal column loads will be in the

order of 1500kN on an approximate 7.5m grid spacing.

The published geological map indicates that the site is underlain by the Whitby Mudstone

Formation, whilst the area adjacent to the west of the site is overlain by the Northampton

Sand Formation. A small area of Alluvium, associated with the River Ise, is present along the

eastern edge of the site. The former topography and subsequent re-grading of the site

suggests that, in addition to these natural strata, made ground is likely to be present beneath

the site, especially in the area of the embankment between the upper and lower playing fields.

The site work, carried out on 21st and 22

nd December 2009, included the sinking of eight

drive-in window sampler boreholes to depths of 4.0m.bgl and five dynamic probe holes to

depths of 5.0m.bgl. The exploratory holes advanced during the site investigation indicate that

the geology generally comprises a variable thickness of Made Ground and Fill (up to

maximum thicknesses of 1.40m and 2.60m respectively), overlying the Northampton Sand

Formation, in turn overlying the Whitby Mudstone Formation. Along the eastern edge of the

site, the Northampton Sand Formation had been eroded by the River Ise, and Alluvium had

been deposited in its place. No significant visual / olfactory contamination was identified

within the strata encountered in the exploratory holes on site.

The ground conditions at the western end of the upper field appear suitable for the design and

construction of relatively shallow spread foundations for the proposed development.

However, in view of the nature and thickness of the Made Ground and Fill towards the eastern

end of the upper field and the anticipated high loading, piles may provide the most appropriate

foundation solution. Alternatively, ground improvement by installation of vibro-stone columns

through the Made Ground and Fill can be also be considered.

It is considered that the ground will be able to support a build up of the proposed fill in relation to

the building up of the field to accommodate the proposed surface water drainage attenuation

tanks in the lower eastern part of the site.

Ground bearing floor slabs can be adopted, providing a well compacted, suitable granular fill is

placed at the formation level. Appropriate measures to reduce impact from the differential

settlements at the location where the slab passes from the natural ground to a structural fill

should be introduced.

In accordance with BRE Special Digest 1: 2005 Concrete in aggressive ground, the

Aggressive Chemical Environment for Concrete (ACEC) Classification is AC-2 with a Design

Sulfate Class for the site of DS-2. However, it is noted that a pH of 5.2 was recorded in

GWS19, which would indicate an ACEC classification of AC-4z. However, as this low pH was

detected in only one of the 13 samples tested, and the average pH of the samples tested from

the site is 6.7, it is considered that this result can be discounted.


7.2 Recommendations for Further Geotechnical Work

From the data already collected from both site investigations, it is not possible to determine

where the large thickness of Made Ground and Fill within the slope between the upper and

lower playing fields ends. Delineating this thick Made Ground and Fill, and knowing its profile

closer to the embankment would be greatly advantageous. The number and placement of

vibro-stone columns will be affected by the size of the area where the depth of the Made

Ground / Fill exceeds the depth to which material will be excavated from.

Report No. 251076-01 BSF Kettering Science Academy

FIGURES

Extract of 1:50,000 Ordnance Survey Explorer Map

Reproduced from Ordnance Survey mapping with the permission of the Controller of Her Majesty’s Stationery Office. Crown Copyright reserved (Licence No: 100002620).

Site: BSF Kettering Science Academy Client: Kier Marriott

National Grid Reference: SP 879 784 Scale: Not to Scale

Job No: 251076

SITE LOCATION PLAN

Fig No: 1

The Site

Site: BSF Kettering Science Academy Client: Kier Marriott

Source: Mott MacDonald’s Northamptonshire

Academies Geo-Environmental Site Fact Sheet (Figure 1 – Site Location)

Scale: Not to Scale

Job No: 251076

SITE LAYOUT PLAN

Fig No: 2

WS6

WS3

WS4

WS1 WS5

WS2

WS7

WS8

DP1

DP2

DP3

DP4

DP5

Sheet 1 of 1

Job Number: 251076

Figure: 5BSF Kettering Science Academy

Client:

Kier Marriott

SPT 'N' VALUES vs DEPTH

Site:

-4.5

-4

-3.5

-3

-2.5

-2

-1.5

-1

-0.5

0

0 5 10 15 20 25 30

SPT 'N' Value (for 300mm penetration)

Dep

th b

elo

w e

xis

tin

g g

rou

nd

level

Alluvium Made Ground Northampton Sand Formation Whitby Mudstone Formation

Report No. 251076-01 BSF Kettering Science Academy

APPENDIX A

Fieldwork Records

BOREHOLE RECORD(Window Sampler)

BoreholeNumber:

Site:

Client: Ground Level: Job No.:

GROUND WATER SAMPLES/TESTS STRATA RECORDStrike Well Depth Type/Depth Depth Level Key Description

(m) (m) (mAOD)

Remarks and Water Observations

Figure:

Logged by:

Scale:

Dates:

S Specialist Engineering, Materialsand Environmental Consultants

Location:

(m)In-situ Tests

HV-Hand Vane (kN/m2)PP-Pocket Penotometer (kN/m2)

MP-Mackintosh Probe (N150)

Key for Insitu tests


Kier Marriott

Hand-dug pit excavated to 1.00m.bgl. No services wereencountered. Groundwater was encountered as seepage at 0.30m.bgl;field is known to be frequently waterlogged. Hole advanced to4.00m.bgl, with an SPT carried out at its base, and was backfilledand compacted on completion.

Deeble Road, Kettering

67.25mAOD 21 Dec 09 251076

WS1

MG

TB1

TB2

TB3

TB4

1.00

2.00

3.00

4.00

C

N=8

HV@ 1.90=117

C

N=14

HV@ 2.90=120

C

N=17

HV@ 3.90=120

C

N=24

150

160

165

0.50

1.50

4.00

66.75

65.75

63.25

0.50

1.00

2.50

Firm to stiff dark orange brown laminated greyslightly silty CLAY with rare rootlets and raresubangular to subrounded fine flint gravel. (MADEGROUND)

Stiff dark grey brown laminated and mottled lightbrown occasionally dark orange silty CLAY with raredecayed rootlets and occasional iron-richlaminations. (NORTHAMPTON SAND FORMATION)

Stiff to very stiff dark grey silty CLAY withselenite present. (WHITBY MUDSTONE FORMATION)

End of Borehole at 4.45 m

1

2

3

4

1:25

Sheet 1 of 1


BoreholeNumber:

Site:



(m) (m) (mAOD)


Figure:

Logged by:

Scale:

Dates:


Location:

(m)In-situ Tests





Kier Marriott

Hand-dug pit excavated to 1.00m.bgl. No services wereencountered. Groundwater was encountered as seepage at 0.50m.bgl;field is known to be frequently waterlogged. Hole advanced to4.00m.bgl, with an SPT carried out at its base, and was backfilledand compacted on completion.


66.72mAOD 21 Dec 09 251076

WS2

MG

TB1

TB2

TB3

TB4

1.00

2.00

3.00

4.00

C

N=7

HV@ 1.90=100

C

N=8

HV@ 2.90=115

C

N=17

HV@ 3.90=114

C

N=22

100

130

125

130

0.20

2.20

4.00

66.52

64.52

62.72

0.20

2.00

1.80

Turf over firm orange brown slightly silty slightlygravelly CLAY with rare rootlets and tin fragments. Gravel is subangular to subrounded fine to mediumflint. (MADE GROUND)

Firm to stiff dark grey laminated orange silty CLAYwith rare decayed rootlets. (NORTHAMPTON SANDFORMATION)



1

2

3

4

1:25

Sheet 1 of 1


BoreholeNumber:

Site:



(m) (m) (mAOD)


Figure:

Logged by:

Scale:

Dates:


Location:

(m)In-situ Tests





Kier Marriott

Hand-dug pit excavated to 1.00m.bgl. No services wereencountered. Groundwater not visibly encountered. Hole advancedto 4.00m.bgl, with an SPT carried out at its base, and was backfilledand compacted on completion.


64.85mAOD 21 Dec 09 251076

WS3

MG

TB1

TB2

TB3

TB4

TB5

1.00

1.30-1.40

2.00

3.00

4.00

C

N=6

C

N=8

HV@ 2.90=117

C

N=11

HV@ 3.90=113

C

N=19

75

80

120

0.80

3.50

4.00

64.05

61.35

60.85

0.80

2.70

0.50

Turf over firm orange brown slightly silty slightlygravelly CLAY with rare rootlets and medium gravelsized clinker fragments. Gravel is subangular tosubrounded fine to medium flint. (MADE GROUND)

…@ 0.40m half brick

Firm to stiff orange brown laminated orange slightly silty slightly gravelly CLAY with rare sandstonecobbles and with rare decayed rootlets andoccasional iron-rich laminations. Gravel issubangular to subrounded fine to medium sandstone.(NORTHAMPTON SAND FORMATION)

… between 1.30m and 1.40m frequent fine gravel sized black organic fragments… between 1.40m and 1.60m yellow grey brown

… between 1.70m and 2.00m no recovery

… below 2.10m becomes firm to stiff and darkgrey mottled light brown, with selenitepresent… between 2.30m and 2.60m occasional to somelaminations of ferruginous sandstone SAND andfine GRAVEL

… below 2.80m dark orange iron-richlaminations



1

2

3

4

1:25

Sheet 1 of 1


BoreholeNumber:

Site:



(m) (m) (mAOD)


Figure:

Logged by:

Scale:

Dates:


Location:

(m)In-situ Tests





Kier Marriott

Hand-dug pit excavated to 1.00m.bgl. No services wereencountered. Groundwater was not visibly encountered. Holeadvanced to 4.00m.bgl, with an SPT carried out at its base, and wasbackfilled and compacted on completion.


64.30mAOD 21 Dec 09 251076

WS4

MG

TB1

TB2

TB3

TB4

1.00

2.00

2.80

4.00

C

N=7

C

N=8

C

N=10

HV@ 3.90=73

C

N=12

105

55

0.60

1.25

2.00

3.20

3.40

4.00

63.70

63.05

62.30

61.10

60.90

60.30

0.60

0.65

0.75

1.20

0.20

0.60

Turf over firm orange brown slightly silty slightlygravelly CLAY with rare rootlets, fine gravel sizedclinker fragments, and medium gravel sized brickfragments. Gravel is subangular to subrounded fineto medium flint and orange ferruginous sandstone.(MADE GROUND)

Firm to stiff orange brown slightly silty slightlygravelly CLAY with rare decayed rootlets. Gravel is angular to subrounded fine to medium occasionallycoarse orange ferruginous sandstone. (FILL)

Firm brown slightly silty slightly sandy slightlygravelly CLAY with occasional ferruginous sandstonecobbles and with rare fine to medium gravel sizedclinker fragments. (FILL)

…@ 1.80m slag cobble within a large cobblesized pocket of light grey brown fine tomedium sand… between 1.90m and 2.00m mottled black, witha high organic / decayed plant fragmentcontent

Firm to stiff dark yellow grey slightly siltyslightly sandy CLAY. Sand is fine to medium.(FILL)

… between 2.30m and 3.00m no recovery, assampler barrel split

Firm to stiff grey brown sandy to very sandy CLAY.(NORTHAMPTON SAND FORMATION)

Stiff to very stiff brown mottled light greyslightly silty occasionally slightly sandy CLAY with occasional layers of orange ferruginous clay.(NORTHAMPTON SAND FORMATION)


1

2

3

4

1:25

Sheet 1 of 1


BoreholeNumber:

Site:



(m) (m) (mAOD)


Figure:

Logged by:

Scale:

Dates:


Location:

(m)In-situ Tests





Kier Marriott

Hand-dug pit excavated to 1.00m.bgl. No services wereencountered. Groundwater was encountered as seepage at 0.30m.bgl,and was sitting in the previously dug hand pit at approximately0.90m.bgl; field is known to be frequently waterlogged. Holeadvanced to 4.00m.bgl, with an SPT carried out at its base, and wascompacted on completion.


65.75mAOD 21 Dec 09 251076

WS5

MG

TB1

TB2

TB3

TB4

1.00

2.00

3.00

4.00

C

N=5

HV@ 1.90=74

C

N=7

C

N=13

C

N=22

50

135

60

0.90

1.10

1.60

1.80

2.00

2.70

3.50

3.70

4.00

64.85

64.65

64.15

63.95

63.75

63.05

62.25

62.05

61.75

0.90

0.20

0.50

0.20

0.20

0.70

0.80

0.20

0.30

Turf over firm orange brown slightly silty slightlysandy slightly gravelly to gravelly CLAY with raresandstone cobbles and with rare rootlets, finegravel sized clinker fragments, and fine to mediumgravel sized brick fragments. Sand is fine tomedium. Gravel is angular to subrounded fine tomedium ferruginous sandstone. (MADE GROUND)

Firm to stiff dark grey mottled orange and paleyellow slightly silty slightly gravelly CLAY withrare decayed rootlets. Gravel is subangular tosubrounded fine to medium sandstone. (FILL)

Firm to stiff dark orange brown mottled greyslightly silty slightly sandy slightly gravellyCLAY. Gravel is subangular to subrounded fine tomedium flint. (FILL)

… between 1.50m and 1.60m dark grey brownmottled black, with frequent decayed plantfragments and rare black wood

Firm to stiff dark orange brown slightly siltyslightly sandy slightly gravelly to gravelly CLAY.Gravel is subangular to subrounded fine to mediumferruginous sandstone and occasional slag. (FILL)

Firm to stiff dark grey brown mottled black slightly silty slightly sandy CLAY with occasional decayedplant fragments. Sand is fine. (FILL)

Soft very wet slightly sandy slightly gravelly CLAY. (FILL)

Firm dark yellow grey slightly silty slightly sandyCLAY. Sand is fine to medium. (FILL)


Firm to stiff orange brown mottled grey slightlysilty slightly gravelly CLAY. (NORTHAMPTON SANDFORMATION)




1

2

3

4

1:25

Sheet 1 of 1


BoreholeNumber:

Site:



(m) (m) (mAOD)


Figure:

Logged by:

Scale:

Dates:


Location:

(m)In-situ Tests





Kier Marriott

Hand-dug pit excavated to 1.00m.bgl. No services wereencountered. Groundwater was sitting in the previously dug hand pitat approximately 1.00m.bgl; field is known to be frequentlywaterlogged. Hole advanced to 4.00m.bgl, with an SPT carried out atits base, and was backfilled and compacted on completion.


62.40mAOD 21 Dec 09 251076

WS6

MG

TB1

TB2

TB3

TB4

1.00

2.00

2.50

3.50

C

N=9

HV@ 1.90=96

C

N=9

C

N=19

C

N=23

50

65

80

0.80

1.30

1.45

1.601.70

2.35

4.00

61.60

61.10

60.95

60.8060.70

60.05

58.40

0.80

0.50

0.15

0.15

0.10

0.65

1.65

Turf over firm dark orange brown slightly siltyslightly sandy slightly gravelly CLAY with rarerootlets. Sand is fine to coarse. Gravel issubangular to subrounded fine flint. (MADE GROUND)

…@ 0.40m rare medium to coarse gravel sizedbrick fragments

… below 0.60m becomes slightly silty slightlysandy gravelly CLAY. Gravel becomes angularto subrounded fine to medium occasionallycoarse ferruginous sandstone

Loose dark orange brown very clayey very gravellyfine to coarse SAND. Gravel is angular tosubrounded fine to medium ferruginous sandstone.(NORTHAMPTON SAND FORMATION)

Loose dark orange brown very clayey very sandyangular to subrounded fine to medium ferruginoussandstone GRAVEL. (NORTHAMPTON SANDFORMATION)

Firm orange brown mottled light grey slightly siltyCLAY. (NORTHAMPTON SAND FORMATION)

Orange brown slightly clayey fine to coarse SAND.(NORTHAMPTON SAND FORMATION)

Firm to stiff orange brown mottled light greyslightly silty CLAY. (NORTHAMPTON SANDFORMATION)

… between 1.90m and 1.92m slightly clayey fine to coarse SAND… between 2.00m and 3.00m 50% recovery



1

2

3

4

1:25

Sheet 1 of 1


BoreholeNumber:

Site:



(m) (m) (mAOD)


Figure:

Logged by:

Scale:

Dates:


Location:

(m)In-situ Tests





Kier Marriott

No services were encountered. Groundwater was sitting atapproximately 0.85m.bgl at the end of drilling; field is known to befrequently waterlogged. Hole advanced to 4.00m.bgl, with an SPTcarried out at its base, and was backfilled and compacted oncompletion.


60.35mAOD 22 Dec 09 251076

WS7

MG

TB1

TB2

TB3

TB4

0.60-0.75

1.50-1.70

2.00-3.00

3.00-4.00

C

N=8

C

N=11

C

N=13

C

N=8

60

30

90

0.25

0.55

1.00

1.35

2.00

3.00

4.00

60.10

59.80

59.35

59.00

58.35

57.35

56.35

0.25

0.30

0.45

0.35

0.65

1.00

1.00

Turf over firm brown slightly silty CLAY with rarerootlets, fine gravel sized clinker/ash fragments,and fine to medium gravel sized brick fragments.(MADE GROUND)

Stiff dark orange brown slightly silty slightlysandy slightly gravelly CLAY with rare rootlets andmedium gravel sized slag fragments. Sand is fine to medium. Gravel is subangular to rounded fine tomedium flint and occasional ferruginous sandstone.(MADE GROUND)

Stiff orange grey brown occasionally mottled darkred brown slightly gravelly CLAY. Gravel issubangular to subrounded fine ferruginous sandstoneand flint. (ALLUVIUM)


Orange grey brown slightly sandy gravelly to verygravelly CLAY. Sand is fine to coarse. Gravel isangular to rounded fine to medium flint. (ALLUVIUM)

… between 1.20m and 1.35m slightly gravellyvery sandy CLAY

Medium dense grey brown very clayey very sandyangular to rounded fine to coarse flint GRAVEL withrare flint cobbles. Sand is fine to coarse.(ALLUVIUM)


Medium dense grey brown clayey very gravelly fine to coarse SAND. Gravel is angular to rounded fine tomedium flint. (ALLUVIUM)

… between 2.00m and 3.00m very limitedrecovery




1

2

3

4

1:25

Sheet 1 of 1


BoreholeNumber:

Site:



(m) (m) (mAOD)


Figure:

Logged by:

Scale:

Dates:


Location:

(m)In-situ Tests





Kier Marriott

No services were encountered. Groundwater was sitting atapproximately 0.80m.bgl at the end of drilling; field is known to befrequently waterlogged. Hole advanced to 4.00m.bgl, with an SPTcarried out at its base, and was backfilled and compacted oncompletion.


60.00mAOD 22 Dec 09 251076

WS8

MG

TB1

TB2

TB3

TB4

1.00

1.65-1.80

2.40

3.00-4.00

HV@ 0.90=80

C

N=5

C

N=16

C

N=18

C

N=15

25

30

105

0.30

1.00

1.40

1.70

3.07

4.00

59.70

59.00

58.60

58.30

56.93

56.00

0.30

0.70

0.40

0.30

1.37

0.93

Turf over firm brown slightly silty CLAY with rarerootlets, fine gravel sized clinker/ash fragments,and fine to medium gravel sized brick fragments.(MADE GROUND)

Stiff dark orange brown slightly silty slightlysandy slightly gravelly to gravelly CLAY with rarerootlets and fine gravel sized clinker/ashfragments. Sand is fine to medium. Gravel isangular to subrounded fine to medium slag andoccasional ferruginous sandstone. (MADE GROUND)

Stiff orange grey brown occasionally mottled darkred brown slightly gravelly CLAY. Gravel issubangular to subrounded fine ferruginous sandstoneand flint. (ALLUVIUM)

Orange grey brown slightly sandy gravelly to verygravelly CLAY. Sand is fine to coarse. Gravel isangular to rounded fine to medium flint. (ALLUVIUM)

Stiff dark grey slightly silty slightly gravellyCLAY. Gravel is angular to rounded fine to mediumflint. (ALLUVIUM)


… between 2.50m and 2.60m very gravelly SAND. Gravel is angular to rounded fine to mediumflint… between 2.60m and 3.00m no recovery

Medium dense grey brown slightly clayey very sandyangular to rounded fine to coarse flint GRAVEL.Sand is fine to coarse. (ALLUVIUM)



1

2

3

4

1:25

Sheet 1 of 1

1:25

Sheet 1 of 1

ReadingsBlows / 100mm

Depth(m)

SDP No

(Nm)

Client:

and Environmental Consultants

Figure:

Scale:

Site:

Ground Level : Date :

Job No. :

Specialist Engineering, MaterialsDYNAMIC PROBINGRECORD FORMLocation:

TorqueDiagram (N100 Values)

Remarks:Recorded by:

Kier Marriott


No services were encountered. Dynamic probe advanced to 5.00m.bgl.


66.430mAOD 22/12/09

MG

DP1251076

00

01

01

12

11

22

22

33

33

54

45

56

56

56

66

77

68

89

87

89

99

910

910

1110

1111

1

2

3

4

5 10 15 20 25

1:25

Sheet 1 of 1


Depth(m)

SDP No

(Nm)

Client:


Figure:

Scale:

Site:


Job No. :




Kier Marriott




64.820mAOD 22/12/09

MG

DP2251076

00

00

11

11

01

12

34

33

33

43

43

44

44

44

54

55

45

55

65

56

77

88

98

89

910

1

2

3

4

5 10 15 20 25

1:25

Sheet 1 of 1


Depth(m)

SDP No

(Nm)

Client:


Figure:

Scale:

Site:


Job No. :




Kier Marriott




66.680mAOD 22/12/09

MG

DP3251076

00

01

11

12

11

23

23

33

43

34

44

54

56

67

77

77

89

98

99

98

109

1010

1111

1011

1211

1

2

3

4

5 10 15 20 25

1:25

Sheet 1 of 1


Depth(m)

SDP No

(Nm)

Client:


Figure:

Scale:

Site:


Job No. :




Kier Marriott




61.500mAOD 22/12/09

MG

DP4251076

00

00

00

10

21

12

22

22

34

33

33

33

44

55

57

66

65

79

88

1011

1011

1111

1210

1112

1111

1

2

3

4

5 10 15 20 25

1:25

Sheet 1 of 1


Depth(m)

SDP No

(Nm)

Client:


Figure:

Scale:

Site:


Job No. :




Kier Marriott




60.300mAOD 22/12/09

MG

DP5251076

00

01

11

21

22

22

33

24

43

22

35

42

12

22

23

34

45

66

76

66

77

87

88

99

99

1

2

3

4

5 10 15 20 25