326 KENSAL ROAD LONDON W10 - rbkc.gov.uk

326 KENSAL ROADLONDON W10

Phase 2Geoenvironmental Investigation

ClientResolution Property Limited

AgentHeyne Tillett Steel

Report No. 4336-2 v2

27 January 2016

CONTENTS

Section Page

SYNOPSIS 1

1 Site description 2

2 Development proposals 2

3 Geology 3

4 Field work 3

5 Laboratory testing 4

6 Ground conditions6.1 Stratigraphy 5

6.1.1 Made Ground 56.1.2 Superficial deposits 66.1.3 London Clay 6

6.2 Groundwater 67 Discussion

7.1 General 77.2 Piled foundations 87.3 Excavations

7.3.1 Stability 97.3.2 Retaining walls 107.3.3 Groundwater 117.3.4 Soil swelling 11

7.4 Contaminant analysis7.4.1 Solid phase 137.4.2 Waste acceptance criteria 14

7.5 Further discussion 157.6 Buried concrete 17

Procedural Notes

APPENDICES

A FiguresB Borehole and Trial RecordsC Laboratory Test Results

Synopsis

An investigation has been carried out on land currently occupied by No. 326

Kensal Road on the instructions of Heyne Tillett Steel, Consulting Engineers to

Resolution Property Limited. A Phase I Environmental Assessment1 has been

prepared for the site and should be read in conjunction with this report. No

other intrusive investigations have been undertaken at the site that we are

aware of.

The purpose of the investigation was to determine the ground conditions and to

provide recommendations in respect of foundation design and other

geoenvironmental matters for the proposed mixed use redevelopment.

Three boreholes and four trial pits were carried out, supported by a programme

of in situ and laboratory testing.

Piled foundations are envisioned for the redevelopment and appropriate design

data is provided. Chemical analysis revealed insufficient contamination to affect

the development.

4336-2 v2

326 KENSAL ROADLONDON W10

Phase 2 Geoenvironmental Investigation

1 Report No. 4336-1 Phase I Environmental Assessment. 326 Kensal Road, LondonW10. AP Geotechnics Ltd., 21 August 2015

1

Site description

The area under investigation is an ‘L’ shaped portion of land extending to some 0.25 hectares

located between Kensal Road and the Grand Union Canal Paddington Branch. The site is

currently occupied by the Saga Centre on the western portion whilst The Old Gramophone

Works covers the remainder. The current general arrangement is given at Figure 1 at

Appendix A.

A full site description is available in the Phase 1 report to which the reader is referred.

2

Development proposals

It is intended to undertake significant remodelling of the site which includes demolishing the

collection of buildings to the rear of the Saga Centre. A basement (double height in part) is

proposed under the entirety of the site comprising The Old Gramophone Works and the

demolished buildings; a part basement exists under the Saga Centre and will be retained. The

Saga Centre will be extended to 5 storeys for commercial space whilst The Old Gramophone

Works and the demolished buildings will be extended to 6 storeys to provide commercial with

residential above.

The basement proposals are shown on Figure 2 of Appendix A. Figure 3 is a section through

the western part of the site (Saga Centre) whilst Figure 4 is a section showing the proposals

for The Old Gramophone Works (OGW).

4336-2 v2 2

3

Geology

Published records of the British Geological Survey (BGS) indicate the site to lie on London

Clay. No superficial deposits are mapped at the subject site.

4

Field work

The extent of the field work was specified by the Consulting Engineer and comprised three

boreholes drilled by light percussive techniques to depths of 10, 20 & 25 m. In addition, four

hand dug trial pits were carried out to ascertain the depth and type of the existing foundations.

Five trial pits were originally specified but TP4 could not be undertaken due to its location.

Trial Pit 1 was started by hand in the small ‘terrace’ at the rear of the OGW but the buried

structures were too deep for hand excavation without shoring. Trial Pit 1 was therefore

moved slightly east and was excavated by machine in the far north east corner of the OGW.

The location of all exploratory points is shown on Figure 1 at Appendix A.

Representative soil samples were recovered from the boreholes and trial pits for subsequent

laboratory examination and testing; whilst Standard Penetration Tests (SPT) were carried out

as appropriate. Details of the strata encountered are provided on the Borehole and Trial Pit

Records at Appendix B; together with particulars of the samples recovered, groundwater

observations and SPT results. The profile of SPT with depth is also presented at Figure 5 of

Appendix A.

A schematic section of the existing foundations are available with the Trial Pit Records at

Appendix B.

4336-2 v2 3

Standpipes were installed in BHs 1 & 3 to allow monitoring of groundwater levels. The results

are discussed in Section 6.2.

5

Laboratory testing

The following laboratory tests were conducted on soil samples recovered during the field

work:-

Natural moisture content: to assess the in situ condition of the soil.

Liquid and Plastic Limits: to classify cohesive soil into behavioural groups.

Unconsolidated undrained triaxial compression: to determine the shear

strength of cohesive material and thus to assess its load bearing capacity.

One-dimensional consolidation: to determine the deformation characteristics

of clay under applied loading and unloading.

Swelling pressure: to ascertain the pressures induced by the excavation for the

basement.

Soluble sulphate and pH value: for the specification of buried concrete.

Contamination: chemical analyses to detect the presence of contaminants as

indicated by the Phase 1 Assessment, viz:-

Metals & metalloids: Total arsenic, cadmium, chromium, copper, lead, mercury, nickel,

selenium and zinc. Water soluble boron and hexavalent

chromium.

Organic: Petroleum hydrocarbons (TPH), polyaromatic hydrocarbons

(PAH) and phenols.

Others: Asbestos screen and Waste Acceptance Criteria

(WAC) full solid waste suite and 2 stage leachate suite.

4336-2 v2 4

Results of these tests are presented at Appendix C and the variation of shear strength with

depth is shown at Figure 6 of Appendix A.

6

Ground conditions

6.1

Stratigraphy

The stratigraphy of the site as revealed by the investigation is described in detail at Appendix B

and in general terms hereafter.

6.1.1

Made Ground

Made Ground was encountered in all exploratory locations under a surfacing of concrete or

tarmac over concrete and was observed to a maximum depth of 2.60 m in BH3.

The Made Ground encountered comprised both cohesive and granular material, the latter

generally comprising fragments of brick, concrete and flint, often in a matrix of silt and sand

sized particles. The cohesive Made Ground was represented by a sandy clay with fragments of

the same man-made detritus found in the granular portion.

Trial pits 1 and 2 were terminated in Made Ground whilst TP5 was terminated in concrete.

The Made Ground in TP1 was odorous and stained with oil.

4336-2 v2 5

6.1.2

Superficial deposits

Although not mapped at this location by the BGS, material underlying the Made Ground in

BH1 and TP3 is not considered representative of London Clay and has been classed as

Superficial deposits for the purposes of this report. The deposit was found to be thin in BH1

where 0.60 m was proved whilst TP3 was terminated in clay at 1.34 m depth. The deposits

were represented by a dark grey and brown mottled clay.

6.1.3

London Clay

London Clay was proved beneath the Made Ground/ Superficial Deposits and continued to the

limit of investigation of 25 m depth.

The London Clay was initially represented by a brown grey clay which is consistent with the

upper, weathered portion of the London Clay and extended to between 7 and 8 m depth.

This was underlain by a fissured dark grey clay which is typical of the unweathered material and

continued to the limit of investigation.

Triaxial testing indicates the weathered London Clay to be firm to stiff whilst the unweathered

portion is stiff to very stiff. An Atterberg Limit performed on a sample of London Clay

confirms the very high plasticity expected of this material.

6.2

Groundwater

Boreholes 1 and 2 and trial pits 2 to 5 were dry during drilling/excavation. Borehole 3

recorded a slow seepage at 4.8 m depth which only rose to 4.75 m during the subsequent 20

4336-2 v2 6

minute observational pause in drilling. However, the speed of drilling and the use of casing to

support the bore may have masked any small inflows and impinged upon the accuracy of the

observations. Trial pit 1 recorded water in the Made Ground below 0.64 m depth.

Details of all groundwater observations during drilling/excavation are provided on the

appropriate Borehole and Trial Pit Record.

Standpipe readings taken during subsequent monitoring visits recorded the depth to

groundwater in BH1 decreasing from 6.40 to 4.66 m whilst water in BH3 rose from 1.66 to

1.54 m depth.

7

Discussion

7.1

General

The site has evidently already carried development and the investigation has revealed Made

Ground to be present. It is possible that other pockets of Made Ground may also be present;

perhaps deeper, of different character or associated with the remains of construction; even

though not detected by this investigation.

All remnants of previous construction should be removed prior to redevelopment to enable

the proposals to be constructed without hindrance and to perform satisfactorily.

In view of the proposed double basement, piled foundations are recommended. However,

when detailed loadings are known, spread foundations might be possible should loading be

appropriate and design information can then be provided.

4336-2 v2 7

7.2

Piled foundations

Either driven or bored piles would be suitable in the ground conditions found at this site.

However, compared with bored piling, construction of driven piles generates greater noise and

vibration which may not be acceptable in this environment. Consideration of the various

advantages and disadvantages of the different pile types suggests CFA piles to be preferred.

They avoid many of the installation difficulties that would otherwise be experienced;

particularly the need for casing through the Made Ground and the need to control

groundwater inflows. Piles constructed by CFA means are therefore recommended and

parameters for their preliminary design are provided in Tables 1 and 2. The recommendation

assumes that suitable access will be available for the necessary plant.

No shaft friction will be generated within 1m of pile cut off level which is assumed to equate to

7 m below Kensal Road.

Table 1: Design parameters for CFA piles - Shaft friction

IgnoreIncreases linearly from 60 to 110 kPa

0.0 - 7.07.0 - 25.0

All materialLondon Clay

Ultimate unit shaft frictionTypicaldepth, m

Stratum

Table 1 has been derived in conjunction with an adhesion factor of 0.6 in the London Clay.

Table 2: Design parameters for CFA piles - End bearing capacity

Increases linearly from 1190 to 2620 kPa15.0 - 25.0 London Clay

Ultimate unit end bearing capacityTypicaldepth, m

Stratum

4336-2 v2 8

Factors of safety must be applied to derive the allowable working load from the ultimate values

given in the tables. Unless successful load tests indicate a lower value may be adopted, a factor

of 3 on both shaft friction and end bearing is recommended.

As an example, the tables predict that a single pile of 450 mm diameter installed to 20.0 m

depth will have an allowable working load of approximately 540 kN. Alternatively. A 600 mm

diameter pile, bored to the same depth would have an allowable load capacity of about

750 kN. Total settlement of such piles is not expected to exceed about 5 - 10 mm as the

working load will be carried wholly in shaft friction.

Evidently it would be possible to utilise other pile types and different geometries. Further

advice could be given on the load capacity for any other configuration which may be under

consideration.

The actual load capacity achieved in practice depends upon the precise installation procedures.

Advice should therefore be sought from specialist contractors to verify the load capacity and

settlement characteristics of their particular piles in the ground conditions revealed by this

investigation.

7.3

Excavations

7.3.1

Stability

All material likely to be encountered in general construction activities should be regarded as

unstable. Some apparent stability may be present immediately on excavation, especially where

4336-2 v2 9

there is a high clay content, but this must not be relied upon. All excavations should therefore

be supported at all times unless battered to a safe angle of repose.

Provision of adequate support is especially important for the safety of personnel when

required to work in or close to excavations. Particular care should be exercised where

excavations are close to existing structures including highways to ensure they do not

experience any loss of support. Temporary and permanent works should be designed to resist

the additional lateral earth pressures arising from any superimposed loads in addition to those

generated by the soil itself, without significant deformation.

Sheet pilling or a secant wall are both possible geotechnical solutions for the temporary works.

A contiguous piled wall is not recommended due to the presence of water at shallow depth.

7.3.2

Retaining walls

Lateral earth pressures will act upon the basement walls and both temporary and permanent

works should be designed to accommodate the lateral earth pressures without significant

deformation, and also any increase that may result from nearby superimposed loadings.

Lateral earth pressures may be calculated in conjunction with the parameters of Table 3.

Table 3: Material parameters in terms of effective stress

20*22*

00

1.82.0

Made GroundLondon Clay

Effective angle of internalshearing resistance,

degrees

Effectivecohesion

BulkdensityMg/m3

Material

* based on engineering assessment

4336-2 v2 10

7.3.3

Groundwater

The two sets of standpipe readings indicate that water was at some 1.5 to 4.6 m depth and is

therefore within the depth of construction.

The chosen method of excavation support will extend down into the London Clay for both

support and to lengthen the flow path for groundwater. Once complete, the basement area

can be pumped out (if required) prior to excavation. Some residual inflows can be expected,

but these should be able to be controlled by conventional pumping from shallow sumps. The

amount of pumping will depend upon the water tightness of the walls but generally results in

low rates of groundwater ingress.

No attempt should be made to lower the general groundwater level as the cone of depression

will extend beyond the site boundaries and may well induce excessive settlement in

surrounding property or other structures.

The basement should be tanked to ensure it is watertight and designed to withstand

hydrostatic uplift forces. It should be noted that these may exceed the dead load of the

structure during the early phases of construction.

Reference to ‘The Lost Rivers of London’ indicates that the site is not located on an historic

water course.

7.3.4

Soil swelling

Excavation of the new basement will reduce the vertical stress that acts upon the soil and thus

generate swelling at formation level. Swelling has two distinct phases; elastic recovery which

4336-2 v2 11

will take place immediately the load is removed followed by long term swelling at decreasing

rate over the ensuing years. The elastic component will be removed during final trimming of

the excavation and is thus likely to be unnoticed.

The magnitude of long term swelling has been assessed from the consolidation test data on the

assumption that the same geological factor applies to swelling as it does to consolidation.

Published data comparing the results of long term monitoring of basement construction with

the magnitude of swelling derived from conventional analysis has indicated that significant

swelling only occurs when the reduction in vertical effective stress is more than 20 % of the

vertical effective stress prior to excavation. This philosophy has been incorporated into the

present analysis.

The estimated long term swelling in the London Clay is calculated at some 50 mm in the

centre of the excavation with approximately half that amount occurring midway along the sides

and one quarter in the corners. A void should therefore be incorporated beneath the

basement slab to allow for the anticipated swelling, or the basement designed to withstand the

uplift forces.

Undisturbed samples have been subject to laboratory swelling tests to determine the swelling

pressure produced by removal of the soil and saturation with water. The results of the

analysis indicate that the swelling pressure is some 50 to 60 % of the weight of the soil

removed.

4336-2 v2 12

7.4

Contaminant analysis

7.4.1

Solid phase

Contaminant testing was undertaken on selected soil samples and the results compared with

the limited number of CLEA2 Soil Guideline Values (SGVs) for commercial land use that have

been published to date. Where not available from that source, reference has also been made

to the LQM/CIEH S4ULs for Human Health Risk Assessment3. Appropriate trigger levels are

given with the results at Appendix C.

Analysis for metals and metalloids revealed all determinands to be below the commercial

triggers.

No phenols were recorded above the limit of detection for the test of 5 mg/kg.

Analysis for TPH recorded very low levels, even from the odorous material in TP1. A

maximum total concentration of 123 mg/kg was recorded in TP1 at 1.5 m depth. None of the

LQM GACs were exceeded. Concentrations of BTEX were recorded in both samples

analysed but at levels below the relevant triggers. The presence of BTEX is the likely source

of the odours noted during the field work.

Five samples were analysed for speciated PAHs, with a maximum of 327 mg/kg total PAH

recorded in BH2 at 0.40 m depth. Only dibenzo(ah)anthracene was recorded above the

4336-2 v2 13

3 The LQM/CIEH S4ULs for Human Health Risk Assessment. Land Quality Press, 2015

2 The Contaminated Land Exposure Assessment Model, Department for Environment, Food and RuralAffairs, The Environment Agency, R & D Publications SGV 1 et al., March 2002

commercial GAC of 3.5 mg/kg with a concentration of 5.4 mg/kg; all other determinands were

below the GAC or less than the limit of detection for the test of 0.1 mg/kg.

Analysis for asbestos was carried out on three samples. No asbestos fibres were detected.

Nevertheless, it is recommended that appropriate health and safety precautions, such as

detailed in HS(G)664 and elsewhere, should be followed by the construction workforce and

others who may come into contact with potentially contaminated soil. They should be agreed

with the Health and Safety Executive and are likely to include, but not be restricted to, the

following:-

maintenance of good standards of personal hygiene.

wearing personal protective clothing that is changed and cleaned frequently to

eliminate skin contact.

prevention of ingestion by using washing and changing facilities at all break

times.

prohibition of eating, drinking or smoking between break times.

controlling the spread of dust and airborne mists to prevent inhalation.

7.4.2

Waste Acceptance Criteria (WAC)

Two samples were subject to the WAC full solid waste suite and the WAC 2 stage leachate

suite. The results have been compared to the criteria contained in the Landfill Regulations

2002 as amended and are presented at Appendix D.

4336-2 v2 14

4 Protection of workers and the general public during the development of contaminated land HS(G)66 Health and Safety Executive, 1991

Within the solid waste suite, all results were within the Inert Waste Landfill criteria limits.

Parameters determined on the compliance leaching test were also predominately within the

Inert Waste Landfill criteria limits save for sulphate and total dissolved solids on both samples.

The results put the waste into the Stable Non-reactive Hazardous waste in non-hazardous

Landfill category.

The contamination test results and the WAC results should be forwarded to the contractor

appointed to undertake any spoil removal. Transfer notes and chain of custody sheets should

be retained for all arisings removed from site.

7.5

Further discussion

The Consulting Engineers have received some preliminary feedback from the Royal Borough of

Kensington & Chelsea (RBKC) regarding the Phase I and Phase 2 reports issued for the site.

The feedback recommends further work is undertaken. The following discussion responds to

the issues raised by RBKC.

The Phase I Assessment revealed that the site has been subject to residential, commercial and

unknown use over the course of its development history. Of particular note was the presence

of a Paint Works on the 1935 map which became a Gramophone Record Works by 1969.

Both of these Works occupied the building known as The Old Gramophone Works. The site

was no longer labelled as a Gramophone Record Works by the mapping of 1987 although it is

understood that it became a recording studio for Trojan Records.

The risk assessment contained within the Phase I report indicated there to be a medium

potential risk of contamination arising from the previous uses of the site. Surrounding uses

form a low risk of potential contamination migrating to the subject site. Although potentially

4336-2 v2 15

contaminative activities have taken place within the vicinity of the subject site, the underlying

London Clay has negligible permeability and is a nonaquifer. The London Clay will severely

retard any migration, both laterally and vertically due to its very low permeability and high

adsorbancy. Any potential contamination on site is therefore unlikely to migrate off site.

Similarly, any off site contamination is unlikely to migrate to the subject site.

Oil filled cables are known to run along the towpath immediately to the north of the site.

Odorous and stained material was encountered in TP1 and is considered to be associated with

a leak from these cables. Other, localised contamination may be present within the site

boundary if the cables have leaked elsewhere. If such material is encountered during

redevelopment works it should be stockpiled separately and tested to ensure correct disposal.

It is beholden on the owners of the oil filled cables to fix any leaks and remediate any land

affected by such leaks.

Whilst it is acknowledged that the Paint Works and Gramophone Works are more likely than

not to have caused some localised contamination, the Phase I Risk Assessment and the Phase 2

recommendations are predicated on the proposal to excavate a large basement (see Figure 2),

resulting in the removal of all potentially contaminated soils within its footprint. Therefore,

there would seem little benefit in testing soils for potential contamination that will be removed

from site, as any potential risk that may have been generated from these soils will have been

removed, thus removing the risk driver.

On sites with a similar mixed use history a Remedial Action Plan has been produced which

outlines the strategies to be employed during the redevelopment works, with particular

emphasis paid to potential contamination and we would consider this an appropriate tool to

allay the Council’s Environmental Quality Officer’s concerns.

4336-2 v2 16

During the course of the development a watching brief shall be maintained under the

supervision of the site manager who should be suitably experienced in managing sites that have

a potential to be ‘contaminated’.

A watching brief consists of a record of any observations of contamination made during the

course of development by any member of staff, including contractors and visitors. In addition,

a photographic record should be kept of key stages of development including any

contamination encountered, formation levels of excavations (including reduced level/mass

excavations) and soft landscaping etc. Staff briefings and a discovery strategy will also be

outlined.

7.6

Buried concrete

Laboratory tests on soil samples yielded a maximum soluble sulphate concentration of 1.46 g/l

which results in a Design Sulphate Class5 of DS-2.

The groundwater is considered to be mobile and all pH determinations were in excess of 6.5.

Therefore the Aggressive Chemical Environment for Concrete, ACEC, is classed as AC-2.

R G ChapmanAP GEOTECHNICS LTD.27 January 2016

This report has been prepared for the sole and specific use of Resolution Property Limited for the purpose of theredevelopment of 326 Kensal Road, London W10 5BZ and should not be relied upon by any third party. Any otherpersons who use any information contained herein without the written permission of AP GEOTECHNICS LTD. do soat their own risk. The copyright to this report remains the property of AP GEOTECHNICS LTD.

4336-2 v2 17

5 Concrete in aggressive ground. BRE Special Digest 1. Building Research Establishment, 2005

PROCEDURAL NOTES for GROUND INVESTIGATIONS

General

This report is based upon data obtained from field descriptions of the strata and examination of the samples by anengineer, together with the results of in situ and laboratory tests as appropriate. Responsibility cannot be acceptedfor variations in ground conditions between and around any of the exploratory points that is not revealed by thedata. Whilst the report may offer an opinion on the ground conditions between exploratory points and below thedepth of investigation, this is for guidance only and no liability is accepted for its accuracy. Unless specificallyincluded in the report, it should be assumed that no testing has been carried out in respect of asbestos or JapaneseKnotweed and no liability is inferred or will be accepted.

Drilling procedure

Boring by light cable percussion drilling allows the ground conditions to be reasonably well established. However, acertain amount of disturbance is inevitable and some mixing of soils can occur.

Sampling procedure

"Undisturbed" samples of predominantly cohesive soils are taken with a 100mm diameter open tube sampler,generally in accordance with BS 5930: 1999.

Where appropriate, or where an undisturbed sample is unsuccessful, disturbed samples are recovered and sealedinto polythene bags.

Groundwater samples are taken when water is encountered in sufficient quantity.

Standard penetration tests

The test is conducted generally in accordance with BS 1377: Part 9: 1990. The sampler tube is subject to a seatingdrive of 150mm into the soil at the base of the borehole. Results are given on the Borehole Records as the numberof blows required to drive the sampler tube a further 300mm and this is known as the “N” value. Where thedriving resistance is such that full penetration is not achieved, the test is generally terminated after 50 blows and theactual distance penetrated is recorded.

Groundwater

Groundwater observations necessarily reflect the conditions encountered at the time of the exploratory work.Long term monitoring of standpipes is usually required to establish an equilibrium water level since the normal rateof boring is too fast to permit steady state conditions to be achieved.

Groundwater levels are subject to variations caused by changes in drainage conditions and seasonal climaticchanges.

Water may necessarily be added to advance the bore whilst casing may be required to maintain an open hole.These can both mask subsequent groundwater observations and are therefore noted on the individual BoreholeRecord.

July 2007

APPENDICES

A Figures

Figure 1: Site PlanFigure 2: Basement PlanFigure 3: Saga Centre SectionFigure 4: The Old Gramophone Works SectionFigure 5: SPT ProfileFigure 6: Shear Strength Profile

B Borehole and Trial Pit Records

Symbols and AbbreviationsBorehole RecordsTrial Pit Records

C Laboratory Test Results

Summary of Geotechnical TestsOne-dimensional consolidationContaminants in SoilWaste Acceptance Criteria

FIGURES

APPENDIX A

© AP GEOTECHNICS LTD. Figure 5

0 5 10 15 20 25 30 35 40 45 50

SPT N Value

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

Dep

th, m

BH1 BH2 BH3

SPT PROFILE326 Kensal Road

London W10

© AP GEOTECHNICS LTD. Figure 6

0 50 100 150 200 250 300

Undrained cohesion, kPa

0

5

10

15

20

25

Dep

th, m

BH1 BH2 BH3

SHEAR STRENGTH PROFILE326 Kensal Road, London W10

BOREHOLE AND TRIAL PIT RECORDS

APPENDIX B

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er

Legend InstrDescriptionDepth

(m)(Thickness)

Depth(m)

Level(mOD)Sample / Tests Field Records

Remarks Scale(approx)

LoggedBy

Figure No.4336.BH1

1:50 ljs

150mm cased to 3.00m

326, KENSAL ROAD, LONDON, W10 5BZ

Resolution Property Limited

Heyne Tillett Steel

BH1

4336

See site plan29/06/2015-30/06/2015

Produced by the GEOtechnical DAtabase SYstem (GEODASY) (C) all rights reserved

Boring Method Casing Diameter

Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

0.5 hrs clean up working area

(0.15) 0.15

CONCRETE with ¾" re-bar

0.5 hrs erecting heras fencing

0.30 D1

Borehole dry

(0.40) 0.55

MADE GROUND: Red brick fragments in a brown sandy clay matrix

0.60 D2 (0.45)

1.00

MADE GROUND: Soft to firm dark grey and black slightly sandy clay with fine gravel of flint, brick and occasional ash

1.10 D31.20-1.65 U1 45 blows (0.60)

1.60

Firm dark grey and brown mottled CLAY

2.00-2.45 U2 45 blows

2.50 D4

3.00-3.45 U3 50 blows

3.50 D5

4.00-4.45 U4 55 blows

4.50 D6

5.00-5.45 U5 55 blows

5.50 D7

6.50-6.95 SPT N=19 3,4/4,4,5,6

(6.10)

7.70

Firm to stiff brown grey CLAY

Stiff to very stiff dark grey CLAY7.90 D88.00-8.45 U6 70 blows

8.50 D9

9.50-9.95 SPT N=24 3,4/5,6,6,7

Excavating from 0.00m to 1.20m for 1.25 hours.

1/3

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4336.BH1

1:50 ljs




Heyne Tillett Steel

BH1

4336

See site plan29/06/2015-30/06/2015



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

Stiff to very stiff dark grey CLAY

(17.30)

....claystone from 10.50m to 10.75m

11.00-11.40 U7 75 blows

11.45 D10

12.50-12.95 SPT N=26 4,4/5,6,8,7

14.00-14.45 U8 75 blows

...becoming fissured14.50 D11

15.50-15.95 SPT N=30 3,5/6,7,8,9

17.00-17.45 U9 80 blows

17.50 D12

18.50-18.95 SPT N=32 4,6/6,8,9,9

Chiselling from 10.50m to 10.75m for 0.25 hours.

2/3

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4336.BH1

1:50 ljs




Heyne Tillett Steel

BH1

4336

See site plan29/06/2015-30/06/2015



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

Stiff to very stiff dark grey CLAY20.00-20.45 U10 85 blows

20.50 D13

21.50-21.95 SPT N=35 4,7/7,8,10,10


23.00-23.45 U11 90 blows

23.50 D14

24.55-25.00 SPT N=36 4,6/8,9,9,10

(17.30)

25.00

25.00 D15

Complete at 25.00m


3/3

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er

LegendDescriptionDepth

(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4336.BH2

1:50




Heyne Tillett Steel

BH2

4336

See site plan30/06/2015-01/07/2015



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

(0.05) 0.05 TARMAC

Borehole dry and backfilled with arisings1 hr waiting to gety onto BH position due to parked vans

(0.15) 0.20

MADE GROUND: Crushed aggregate

0.5 hrs erecting heras fencing

0.40 D1

0.25 hrs reinstating

(0.40) 0.60

MADE GROUND: Soft to firm dark grey and black slightly sandy clay with fine gravel of flint, brick and occasional ash

(0.25) 0.85 CONCRETE (0.40) 1.25 MADE GROUND: Concrete rubble

1.40 D21.50-1.95 U1 50 blows

2.00 D3

2.50-2.95 U2 50 blows

3.00 D4

3.50-3.95 U3 55 blows

4.00 D5

4.50-4.95 SPT N=17 2,3/4,4,4,5

6.00-6.45 U4 60 blows

6.50 D6

(5.95)

7.20

Firm to stiff brown grey CLAY with selenite crystals

7.30 D7

7.50-7.95 SPT N=20 3,4/4,5,5,6

9.05-9.50 U5 70 blows

9.55-10.00 SPT N=23 2,4/5,5,6,79.55 D8

(2.80)

10.00

Stiff fissured dark grey CLAY

Chiselling from 0.60m to 0.85m for 0.25 hours. Chiselling from 0.85m to 1.25m for 0.75 hours. Excavating from 0.00m to 0.85m for 0.5 hours.

10.00 D9

1/1

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4336.BH3

1:50 ljs




Heyne Tillett Steel

BH3

4336

See site plan02/07/2015



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

11

(0.05) 0.05 TARMAC

0.5 hrs clean up working area

(0.05) 0.10

CONCRETE

0.50 D1

1.30-1.75 SPT(C) N=20 4,6/3,7,7,3

(1.90)

2.00

MADE GROUND: Bricks and brick fragments in a matrix of silt and sand sized particles with voids

(0.20) 2.20

CONCRETE

2.30-2.75 SPT(C) N=10 2,2/2,3,3,22.30 D2 (0.40)

2.60

MADE GROUND: Soft brown grey sandy clay with brick fragments

2.80 D3

3.00-3.45 U1 45 blows

3.50 D4

4.00-4.40 U2 45 blows

4.45 D5

slow seepage(1) at 4.80m, rose to 4.75m in 20 mins.

4.80 W1

5.00-5.40 U3 45 blows

5.45 D6

6.50-6.95 SPT N=20 3,3/4,5,5,6


(5.50)

8.10

Firm to stiff brown grey CLAY

Stiff fissured dark grey CLAY8.20 D78.30-8.75 U4 60 blows

8.80 D8

9.80-10.25 SPT N=22 3,4/4,5,6,7

Chiselling from 2.00m to 2.20m for 0.5 hours. Chiselling from 7.90m to 8.15m for 0.25 hours. Excavating from 0.00m to 1.20m for 1.25 hours.

1/2

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4336.BH3

1:50 ljs




Heyne Tillett Steel

BH3

4336




Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

Stiff fissured dark grey CLAY

11.30-11.75 U5 70 blows

11.80 D9

12.80-13.25 SPT N=26 3,5/5,6,7,8

14.30-14.75 U6 75 blows

14.80 D10

15.80-16.25 SPT N=29 2,5/6,7,7,9


17.50-17.95 U7 80 blows

18.00 D11

19.00-19.45 SPT N=32 4,5/7,8,8,9

(11.90)

20.00


20.00 D12

2/2

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)

Level(mOD)Sample / Tests

1:20 4336.TP1



Heyne Tillett Steel

TP1

4336



Plan.

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Trial Pit

DimensionsExcavation Method

WaterDepth(m)

Field Records

Remarks

Scale (approx) Logged By Figure No.

Trial Pit

Floating product on water in base of pitWater in clay below 0.64 m depth.

(0.19)

0.19

CONCRETE

0.50 C1

(0.45)

0.64

MADE GROUND: Fragments of brick, concrete and flint in a clay matrix

1.00 C2

1.50 C3

2.00 C4

(1.52)

2.16

MADE GROUND: Soft grey, brown and black slightly sandy clay with gravel of flint, brick and concrete. Odorous and wet

2.16 C5

Complete at 2.20m

1/2

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)


1:20 4336.TP2



Heyne Tillett Steel

TP2

4336



Plan.

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Trial Pit


WaterDepth(m)

Field Records

Remarks


Trial Pit

(0.17)

0.17

CONCRETE

(0.03) 0.20

MADE GROUND: Grey, black and brown fragments of concrete, flint and bituminous gravel in a matrix of silt and sand sized particles

0.20 C1

Complete at 0.25m

1/2

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)


1:20 4336.TP3



Heyne Tillett Steel

TP3

4336



Plan.

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Trial Pit


WaterDepth(m)

Field Records

Remarks


Trial Pit

(0.09) 0.09

TARMAC

(0.30)

0.39

CONCRETE

0.50 C1 (0.29)

0.68

MADE GROUND: Grey brown fragments of brick, concrete and flint in a matrix of silt and sand sized particles

1.00 C2

(0.50)

1.18

MADE GROUND: Brown gravel of fine to coarse flint and occasional fine brick in a matrix of silt and sand sized particles, locally clayey

1.33 C3

(0.16) 1.34

Soft to firm brown CLAY (wet)

Complete at 1.35m

1/2

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)


1:20 4336.TP5



Heyne Tillett Steel

TP5

4336



Plan.

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Trial Pit


WaterDepth(m)

Field Records

Remarks


Trial Pit

Trial pit excavated through concrete to 0.64 m depth. Hole then drilled to 1.2 m depth and still in concrete. Hole drilled in middle of floor and encountered concrete and hole drilled adjacent to opposite column and found the same. It may therefore be a raft

(0.09) 0.09

CONCRETE

(0.06) 0.15

MADE GROUND: Shingle

(1.05)

1.20

CONCRETE

Complete at 1.20m

1/2

LABORATORY TEST RESULTS

APPENDIX C

Project: 326 KENSAL ROAD, LONDON, W10 5BZ Project No: 4336-2Client: Resolution Property Limited Sheet No: 1/3Agent: Heyne Tillett Steel

CLASSIFICATION TRIAXIAL COMPRESSION - TOTAL STRESS CHEMICALLocation Sample Depth Description Natural Liquid Plastic Plast. Passing Mod. Class Type Moisture Bulk Radial Deviator Cohesion Sulphate (SO4) pH

No Moisture Limit Limit Index 425µm Plast. Content Density Stress Stress cu, kPa cu, kPa Water SoilContent Index assuming Øu, deg (Sol)

m % % % % % % % Mg/m³ kPa kPa Øu = 0 g/l g/l

BH1 U2 2.00 Firm brown grey CLAY UU 27 2.02 40 105 52 0.28 7.99102

U3 3.00 Firm brown grey CLAY UU 27 2.01 60 136 68102

U4 4.00 Stiff brown grey CLAY UU 29 1.98 80 159 80 0.91 8.57102

U5 5.00 Stiff brown grey CLAY UU 32 1.94 100 162 81102

U6 8.00 Stiff dark grey CLAY UU 28 1.98 160 200 100102


U8 14.00 Very stiff dark grey CLAY UU 27 2.01 280 303 151 0.57 8.68102

U9 17.00 Very stiff dark grey CLAY UU 27 2.00 340 339 169102

Note: Soil Classification based upon unmodified Plasticity Index

© AP GEOTECHNICS LTD.

SUMMARY OF GEOTECHNICAL TESTS





BH1 U10 20.00 Very stiff dark grey CLAY UU 26 1.93 400 323 162102

U11 23.00 Very stiff dark grey CLAY UU 25 1.99 460 430 215102

BH2 U1 1.50 Firm brown grey CLAY UU 28 1.97 30 99 50102

U2 2.50 Firm brown grey CLAY UU 30 1.99 50 135 68 1.46 8.45102

U4 6.00 Stiff brown grey CLAY 30 74 29 45 100 CV UU 30 1.95 120 185 92 0.81 7.99102

U5 9.05 Stiff dark grey CLAY UU 30 2.01 181 214 107 1.24 8.64102

BH3 U1 3.00 Firm brown grey CLAY UU 27 2.03 60 115 57 0.88 8.24102

U2 4.00 Firm brown grey CLAY UU 30 1.95 80 66 33(premature failure) 102








BH3 U3 5.00 Firm brown grey CLAY UU 31 1.96 100 116 58102




U7 17.50 Stiff dark grey CLAY UU 26 2.03 350 277 139 0.71 8.22102




Preparation

Orientation wthin sample

Particle density Mg/m3

Specimen details

Diameter mm

Height mm

Moisture Content %

Bulk density Mg/m3

Dry density Mg/m3

Voids Ratio

Saturation %

Average temperature for test oC

Swelling Pressure kPa

Settlement on saturation %

Remarks

Initials

Date:

Test Report by K4 SOILS LABORATORY

Unit 8 Olds Close Olds Approach

Watford Herts WD18 9RU

Tel: 01923 711 288

Email: [email protected]

Checked and Approved

K.P

04/08/2015

2519 Approved Signatories: K.Phaure (Tech.Mgr) J.Phaure (Lab.Mgr) MSF-5-R6 (Rev. 0)

90

0.835 0.764

94 112

1.90 2.02

1.47 1.53

140 0.746 0.12 18.84 18.11

90 0.764 0.21 29.0 31.8

Initial Final

280 0.717 0.022 74.91 -

280 0.765 0.19 8.3 140 0.0018

140 0.812

560 0.707 0.12 15 39 0.0034

kPa m2/MN m2/yr m2/yr Vertical

0.25 26 150 0.0014

90.0 0.835 - - - -

assumed 2.70

Test Method BS1377:Part 5:1990, clause 3 Date Test started 21/07/2015

Applied

Pressure Voids ratioMv

Cv

( t50, log )

Cv

( t90, root )Csec

Project ID 4336 Client AP Geotechnics Depth 8.00

Soil Description High strength fissured dark brown CLAY

Sample Type U

Sample Received 09/08/2015

Schedule received 09/08/2015

Project Started 14/07/2015

ONE DIMENSIONAL CONSOLIDATION TEST Job Ref 19172

Borehole/Pit No. BH1

Site Name Kensal Road Sample No. 6

eo

0.640

0.660

0.680

0.700

0.720

0.740

0.760

0.780

0.800

0.820

0.840

Void

s R

atio

0.00

10.00

20.00

30.00

40.00

50.00

1 10 100 1000 10000

Cv m

2/y

r (

log tim

e)

Applied Pressure kPa

Preparation



Specimen details

Diameter mm

Height mm

Moisture Content %

Bulk density Mg/m3

Dry density Mg/m3

Voids Ratio

Saturation %




Remarks

Initials

Date:




Tel: 01923 711 288



K.P

04/08/2015


53

0.903 0.848

94 106

1.86 1.95

1.42 1.46

100 0.817 0.16 18.90 18.35

53 0.848 0.36 31.3 33.4

Initial Final

200 0.787 0.064 74.78 -

200 0.826 0.26 14 28 0.0023

100 0.873

400 0.765 0.17 10 6.3 0.0028


0.33 31 63 0.0015

53.0 0.903 - - - -

assumed 2.70


Applied


Cv

( t50, log )

Cv

( t90, root )Csec


Soil Description High strength fissured brown CLAY with rare selenite crystals

Sample Type U







eo

0.720

0.740

0.760

0.780

0.800

0.820

0.840

0.860

0.880

0.900

0.920

Void

s R

atio

0.00

10.00

20.00

30.00

40.00

50.00

1 10 100 1000 10000

Cv m

2/y

r (

log tim

e)


Preparation



Specimen details

Diameter mm

Height mm

Moisture Content %

Bulk density Mg/m3

Dry density Mg/m3

Voids Ratio

Saturation %




Remarks

Initials

Date:




Tel: 01923 711 288



K.P

04/08/2015


80

0.887 0.817

91 108

1.86 1.97

1.43 1.49

120 0.799 0.12 18.93 18.23

80 0.817 0.25 29.9 32.8

Initial Final

240 0.767 0.053 75.00 -

240 0.812 0.24 9.7 18 0.0027

120 0.866

480 0.745 0.15 0.89 8.8 0.0033


0.27 11 13 0.0017

80.0 0.887 - - - -

assumed 2.70


Applied


Cv

( t50, log )

Cv

( t90, root )Csec


Soil Description High strength fissured dark grey CLAY

Sample Type U







eo

0.700

0.720

0.740

0.760

0.780

0.800

0.820

0.840

0.860

0.880

0.900

Void

s R

atio

0.00

5.00

10.00

15.00

20.00

25.00

1 10 100 1000 10000

Cv m

2/y

r (

log tim

e)


Project: 326 KENSAL ROAD, LONDON, W10 5BZ Project No: 4336Client: Resolution Property Limited Sheet No: 1/1Agent: Heyne Tillett Steel

Loca

tion

Sample

Depth

Arsenic

Cadmium

Chrom

ium

Coppe

r

Lead

Merc

ury

Nickel

Selen

ium

Zinc

Boron

Chrom

ium

Phen

ols

Organ

ic Carb

on

TPH by

GCM

S

m

triva

lent

inorg

anic

water s

ol.

hexa

valen

ttot

. mon

ohyd

ric

tot.

C8 - C

10

C10 -

C12

C12 -

C16

C16 -

C21

C21 -

C35

C35 -

C40

Total

C8 -

C40

pH

BH1 D1 0.30 17.4 <0.5 34.8 32.9 146 0.7 26.3 <1.0 71.4 1.2 <0.8 <5 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0

BH2 D1 0.40 22.7 <0.5 40.5 59.5 329 0.9 32.6 1.3 334 2.9 <0.8 <5 <1.0 <1.0 <1.0 <1.0 4.8 <1.0 4.8

TP1 C1 0.50 22.9 1.3 40.4 53.6 601 1.0 26.6 <1.0 217 1.0 <0.8 <5 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0 <1.0C2 1.00 <5

GAC¹ residential 3 627 2330 3750 291 4.3 210 commercial 348 8840 71700 665000 192000 35 1100000

CLEA² residential 32 170 130 350commercial 640 3600 1800 13000

Notes All units are mg/kg dry weight of soil unless otherwise stated, except for pH which is dimensionless

1. LQM/CIEH GAC given at 1% soil organic matter

2. CLEA SGVs given at 6% soil organic matter Exceptions denoted thus: Residential XXCommercial XX


CONTAMINANTS IN SOIL


Speciated Polyaromatic Hydrocarbons by GCMSLocation BH1 BH2 TP1 TP1 TP1 LQM/CIEHSample D1 D1 C1 C2 C3 GAC³

Depth, m 0.30 0.40 0.50 1.00 1.50 residential allotments commercial

Determinand Concentration, mg/kg

PAHNaphthalene <0.1 1.2 <0.1 0.3 16.1 1.5 4.1 200Acenaphthylene <0.1 4.7 <0.1 <0.1 0.2 170 28 84000Acenaphthene <0.1 0.2 <0.1 <0.1 8.6 210 34 85000Fluorene <0.1 0.5 <0.1 <0.1 6.3 160 27 64000Phenanthrene <0.1 7.2 <0.1 <0.1 20.1 92 16 22000Anthracene <0.1 4.5 <0.1 <0.1 2.5 2300 380 530000Fluoranthene 0.1 57.5 0.1 0.2 6.7 260 52 23000Pyrene 0.1 53.1 0.1 0.1 4.5 560 110 54000Benzo(a)anthracene <0.1 32.8 0.1 0.1 1.1 3.1 2.5 90Chrysene 0.1 35.4 0.1 0.2 1.5 6.0 2.6 140Benzo(b)fluoranthene <0.1 26.9 <0.1 0.1 0.6 5.6 3.5 100Benzo(k)fluoranthene <0.1 26.6 <0.1 0.2 0.5 8.5 6.8 140Benzo(a)pyrene 0.1 33.4 0.2 0.4 0.5 0.83 0.6 14Indeno(123-cd)pyrene <0.1 19.9 <0.1 0.2 0.7 3.2 1.8 60Dibenzo(ah)anthracene <0.1 5.4 <0.1 0.3 0.3 0.76 0.76 13Benzo(ghi)perylene <0.1 17.5 <0.1 0.5 0.5 44 70 650

Total PAH (16) <0.4 327 0.8 2.8 70.7

Notes

1. Total PAH = Sum of EPA16 identified components Exceptions denoted thus: Residential XX2. The results are expressed as mg/kg dry weight soil after correction for moisture content Commercial XX3. GAC given at 1% soil organic matter




Speciated Total Petroleum Hydrocarbons (Aromatic / Aliphatic Split with BTEX)Location TP1 TP1 LQM/CIEHSample C2 C3 GAC

Depth, m 1.00 1.50 residential allotments commercial

Determinand Concentration, mg/kg

Aromatic HydrocarbonsC5 - C7 0.04 <0.01 65 13 28000>C7 - C8 0.13 0.02 120 22 59000>C8 - C10 <1.0 <1.0 27 9 3700>C10 - C12 <1.0 9.7 69 13 17000>C12 - C16 <1.0 34.4 140 23 36000>C16 - C21 <1.0 47.9 250 46 28000>C21 - C35 21 30.9 890 370 28000>C35 - C40 <1.0 <1.0Total Aromatic Hydrocarbons 21.17 122.92

Aliphatic HydrocarbonsC5 - C6 <0.01 <0.01 30 740 3400>C6 - C8 1.02 0.02 73 2300 8300>C8 - C10 5.7 <1.0 19 320 2100>C10 - C12 6.6 <1.0 93 2200 10000>C12 - C16 <1.0 <1.0 740 11000 61000>C16 - C21 <1.0 <1.0>C21 - C35 32.4 <1.0>C35 - C40 3.9 <1.0Total Aliphatic Hydrocarbons 45.7 <1.0

Total Petroleum Hydrocarbons 70.8 123

BTEX Concentration, µg/kg

Benzene 35.2 <10.0 330 70 95000Toluene 133 16.9 610000 120000 4400000Ethyl Benzene 49.1 177 350000 90000 2800000Xylenes* 112 356 230000 160000 2600000

NotesTotal = Sum of compounds above detection limit.GAC given at 1% soil organic matter Exceptions denoted thus: Residential XX*Results given as total of (ortho), (meta) and (para) xylene. SGV given is the lowest permissible value for any xylene compound Commercial XX



45000 260000 1600000


Location Sample Depth Asbestos identificationm Description of matrix Overall percentage of asbestos identified (approx.) Type of asbestos identified

BH1 D1 0.30 MADE GROUND none detected

BH2 D1 0.40 MADE GROUND none detected

TP1 C1 0.50 MADE GROUND none detected



Documents

326 KENSAL ROAD LONDON W10 - rbkc.gov.uk