GROUND
MOVEMENT ASSESSMENT REPORT
134 Old Street London EC1 Client: YPP Ltd Engineer: Gurney Consulting Engineers J16116A
July 2016
134 Old Street, London EC1V
9BL YPP Ltd
Ground Movement
Assessment Report
Document Control
Project title
134 Old Street, London, EC1V 9BL
Project ref
J16116A
Report prepared by
Jack Deaney BSc FGS
Martin Cooper BEng CEng MICE FGS
Report checked and
approved for issue by
Steve Branch BSc MSc CGeol FGS FRGS MIEnvSc
Issue No
Status
Date
1
Final
28 July 2016
Approved for Issue
This report has been issued by the GEA office indicated below. Any enquiries regarding the report should be directed to the
office indicated or to Steve Branch in our Herts office.

Hertfordshire
tel 01727 824666
[email protected]
Nottinghamshire
tel 01509 674888
[email protected]
Geotechnical & Environmental Associates Limited (GEA) disclaims any responsibility to the Client and others in respect of
any matters outside the scope of this work. This report has been prepared with reasonable skill, care and diligence within the
terms of the contract with the Client and taking account of the manpower, resources, investigation and testing devoted to it in
agreement with the Client. This report is confidential to the Client and GEA accepts no responsibility of whatsoever nature
to third parties to whom this report or any part thereof is made known, unless formally agreed beforehand. Any such party
relies upon the report at their own risk. This report may provide advice based on an interpretation of legislation, guidance
notes and codes of practice. GEA does not however provide legal advice and if specific legal advice is required a lawyer
should be consulted.
© Geotechnical & Environmental Associates Limited 2016
Ref J16116A
Issue No 1
28 July 2016
i
134 Old Street, London EC1V
9BL YPP Ltd
Ground Movement
Assessment Report
CONTENTS
1.0
INTRODUCTION
1.1 Proposed Development
1.2 Limitations
1
1
1
2.0
THE SITE
2.1 Site Description
2
2
3.0
SUMMARY OF GROUND CONDITIONS
3
4.0
CONSTRUCTION SEQUENCE
3
5.0
GROUND MOVEMENTS
5.1 Ground Movements - Surrounding the Basement
5.2 Movements within the Excavation (Heave)
3
4
6
6.0
DAMAGE ASSESSMENT
6.1 Damage to Neighbouring Structures
6.2 Monitoring of Ground Movements
7
7
8
7.0
CONCLUSIONS
9
APPENDICES
Ref J16116A
Issue No 1
28 July 2016
ii
134 Old Street, London EC1V
9BL YPP Ltd
1.0
Ground Movement
Assessment Report
INTRODUCTION
Geotechnical and Environmental Associates (GEA) has been commissioned by Gurney
Consulting Engineers, on behalf of YPP Ltd, to complete a ground movement assessment for
the proposed construction of a new single level basement beneath No 134 Old Street, London,
EC1V 9BL.
A Desk Study and Ground Investigation Report has previously been carried out by GEA
(report ref J16116, dated July 2016) and the findings of the report have been used in the
derivation of parameters for use in this assessment.
The purpose of this assessment has been to assess any effects of the proposed basement
construction upon nearby sensitive structures.
1.1
Proposed Development
Consideration is being given to the redevelopment of the site through the demolition of the
existing buildings and construction of a five-storey mixed use building with single-storey
partial basement, extending to a depth of approximately 4.0 m.
The plan below shows the proposed development.
This report is specific to the proposed development and the advice herein should be reviewed
once the development proposals are finalised.
Ref J16116A
Issue No 1
28 July 2016
1
134 Old Street, London EC1V
9BL YPP Ltd
1.2
Ground Movement
Assessment Report
Limitations
The conclusions and recommendations made in this report are limited to those that can be
made on the basis of the investigation. The results of the work should be viewed in the
context of the range of data sources consulted, the number of locations where the ground was
sampled and the number of soil, gas or groundwater samples tested; no liability can be
accepted for information in other data sources or conditions not revealed by the sampling or
testing. Any comments made on the basis of information obtained from the client or other
third parties are given in good faith on the assumption that the information is accurate; no
independent validation of such information has been made by GEA.
2.0
THE SITE
2.1
Site Description
The site is located approximately 300 m west of Old Street London Underground Station and
is bounded by Old Street to the north, a six-storey mixed use building to the west, a fivestorey office block to the east and a three-storey residential block to the south. It can also be
located by National Grid Reference 532460, 182390.
The site forms a roughly L-shaped area measuring approximately 15 m by 8 m at its greatest
extent and is occupied by a two-storey plus roof accomodation. The western half of the
building, comprises only the second floor and overhangs an access route to Tilney Court,
which forms an external communal area for the residential block bounding the south of the
site as seen on the photograph below.
The external ground surface dips slightly to the south from 19.7 m OD to 19.4 m OD. The
ground floor level within the building is sensibly level across site at 20.15 m OD.
The site and surrounding area are completely covered in hardstanding and devoid of any
vegetation.
Ref J16116A
Issue No 1
28 July 2016
2
134 Old Street, London EC1V
9BL YPP Ltd
3.0
Ground Movement
Assessment Report
SUMMARY OF GROUND CONDITIONS
Beneath a relatively significant thickness of made ground, the Hackney Gravel was
encountered, underlain by the London Clay Formation.
The made ground varied in thickness, extending to 5.3 m (14.85 m OD) in the north and to
2.40 m (17.75 m OD) it the south. Its composition was relatively consistent in that it
comprised silty sand or sandy clay with fragments of brick, shells, concrete, pottery, ash,
decaying wood, flint and coal. In the area around Borehole No 1 a slight hydrocarbon odour
was noted.
The Hackney Gravel comprised an initial layer of soft becoming firm brown very sandy clay
which extended to depths of between 5.10 m and 6.0 m (14.4 m OD and 14.15 m OD), where
it graded into a dense brown fine to coarse grained gravelly sand with partings of firm clay to
a depth of 6.7 m (13.45 m OD).
The London Clay Formation comprised an initial layer of firm brown mottled grey slightly
fissured silty clay to a depth of 8.0 m (11.5 m OD) where it was underlain by a firm becoming
stiff fissured blueish grey silty clay to the maximum depth investigated, of 15.0 m (4.5 m
OD).
According to local BGS archive records the base of the London Clay is at a depth of
approximately 25.0 m (-4.85 m OD), where it is underlain by the Lambeth Group Formation.
4.0
CONSTRUCTION SEQUENCE
For the purposes of the ground movement assessment, the datum is taken as the existing
ground floor level, at an arbitrary level of zero. It is proposed to construct a basement to 4.0 m
depth beneath the existing ground floor level across the majority of the footprint of the
building. The proposed basement wall adjoining 1-5 Tilney Court will be formed by means of
traditional underpinning to a depth of 4.0 m below existing ground floor level, whilst the
other three walls will be formed by means of a contiguous piled wall embedded to 12.0 m
depth below existing ground floor level.
The following sequence of operations has been assumed to enable analysis of the ground
movements around the proposed basement both during and after construction.
In general, the sequence of works for basement construction will comprise the following
stages.
1.
Construct underpinned retaining walls. These are commonly formed in a ‘hit and
miss’ sequence using a trench box excavation, commonly sheet lined, shored and
strutted; all temporary shoring and propping to be inspected by a suitably qualified
person;
2.
Construct contiguous piled walls; and
3.
excavate new basement and temporarily retain and strengthen, with sufficient
propping and walling beams, the new retaining walls. Construct new ground beams.
The underpins will be adequately laterally propped and sufficiently dowelled together,
concrete cast and adequately cured prior to excavation of the basement and removal of the
formwork and supports. It is assumed that the corners of the excavation will be supported by
Ref J16116A
Issue No 1
28 July 2016
3
134 Old Street, London EC1V
9BL YPP Ltd
Ground Movement
Assessment Report
cross-bracing or similar and that the new retaining walls will not be cantilevered at any stage
during the construction process.
The detail of the support provided to adjacent walls is beyond the scope of this report at this
stage and the structural engineer will be best placed to agree a methodology with the
underpinning contractor once appointed.
When the final excavation depths have been reached the permanent works will be formed,
which are likely to comprise reinforced concrete walls with a drained cavity lining the inside
of the underpinned wall. Reinforced concrete will be used for the floor slabs and it is
anticipated that heave protection may be installed beneath the basement slab. Following this,
the floor slab will be constructed at basement depth and the temporary props will be removed.
5.0
GROUND MOVEMENTS
An assessment of ground movements within and surrounding the excavation has been
undertaken using the X-Disp and P-Disp computer programs licensed from the OASYS suite
of geotechnical modelling software from Arup. These programs are commonly used within
the ground engineering industry and are considered to be appropriate tools for this analysis.
The X-Disp program has been used to predict ground movements likely to arise from the
construction of the proposed basement. This includes the settlement of the ground (vertical
movement) and the lateral movement of soil behind the proposed retaining walls (horizontal
movement).
The analysis of potential ground movements within the excavation, as a result of unloading of
the underlying soils, has been carried out using the Oasys P-Disp Version 19.3 – Build 12
software package and is based on the assumption that the soils behave elastically, which
provides a reasonable approximation to soil behaviour at small strains.
For the purpose of these analyses, the corners have been defined by x and y coordinates. In
the X-Disp and P- Disp analyses the x-direction is roughly parallel with the orientation eastwest, whilst the y-direction is roughly parallel with the orientation north-south. Vertical
movement is in the z-direction. The walls of the existing structures in and surrounding the
site have been modelled as 1.0 m long structural elements if the wall is less than 10 m long, or
as 2.0 m long structural elements if the wall is greater than 10 m long. The full outputs of all
the analyses can be provided on request and samples of the output movement contour plots
are included within the appendix.
5.1
Ground Movements – Surrounding the Basement
5.1.1
Model Used
For the X-Disp analysis, the soil movement relationships used for the embedded retaining
walls are the default values within CIRIA report C5801, which were derived from a number of
historic case studies.
Whilst it might appear reasonable to adopt the ground movement curves for ‘no horizontal
and vertical movement’ for this analysis, in practice there will always be a potential for some
movement to take place. There is a wealth of experience with respect to the construction of
underpinned retaining walls beneath existing structures, suggesting that ground movements
1
Gaba, A, Simpson, B, Powrie, W and Beadman, D (2003) Embedded retaining walls – guidance for economic design. CIRIA
Report C580.
Ref J16116A
Issue No 1
28 July 2016
4
134 Old Street, London EC1V
9BL YPP Ltd
Ground Movement
Assessment Report
should remain typically within the range of 2 mm to 5 mm following completion of the
works, provided that they are installed by a reputable and experienced contractor in
accordance with the guidelines published by the Association of Specialist Underpinning
Contractors2.
The analysis has adopted the values for ‘installation of a planar diaphragm wall’ to represent
the installation of the underpinned and reinforced concrete retaining walls, whilst the values
for ‘installation of a contiguous bored piled wall in stiff clay’ have been adopted to represent
the installation of the contiguous bored piled wall. The ground movement curves for
‘excavations in front of a wall in sand’ have been adopted as most appropriate for the
proposed excavation and its support at this site as the walls will be generally supporting
granular soils.
5.1.2
Results
The predicted movements are based on the worst case of the individually analysed segments
of ‘hogging’ and ‘sagging’ and these are summarised in the tables overleaf. It should be
noted that the combined effect of segments acting together typically improve the resultant
movements and the values below are therefore deemed to be conservative. The diagram
below details the relevant sensitive structures in relation to the proposed excavations.
Displacement Analysis Points:
The building height for each of the nearby sensitive structures has been derived from
drawings (0423-4-F-200-00, dated May 2015 and 0423-4-F201-00, dated May 2015) as
supplied by the consulting engineer. As no basements are known to be present nearby and in
2
Haslam S, O’Connor L (2013) Guidelines on safe and efficient basement construction directly below or near to existing
structures ASUC
Ref J16116A
Issue No 1
28 July 2016
5
134 Old Street, London EC1V
9BL YPP Ltd
Ground Movement
Assessment Report
the absence of foundation information for each structure, a foundation depth of 1 m below
ground level has been assumed.
The movements predicted by X-Disp are summarised in the table below; the results are
presented below and in subsequent tables to the degree of accuracy required to allow
predicted variations in ground movements around the structure to be illustrated, but may not
reflect the anticipated accuracy of the predictions.
Wall Movement (mm)
Phase of Works
Vertical Settlement
Horizontal Movement
Installation of retaining walls
<5
<5
Combined Retaining Wall and
Excavation Movements
5 to 17
<5
The analysis has indicated that the maximum vertical and horizontal settlements that will
result from wall installation are likely to be less than 5 mm.
The movements arising from the combined wall installation and excavation phases are not
likely to exceed 17 mm of vertical settlement, whilst the maximum horizontal movements are
not anticipated to exceed 5 mm.
The estimated movements are considered to represent a worst case scenario, particularly as
the movements resulting from basement excavation will be minimised due to control of the
propping in the temporary works.
5.2
Movements within the Excavation (Heave)
5.2.1
Model Used
At this site unloading of the London Clay under the Hackney Gravel will take place as a result
of the proposed basement excavation and the reduction in vertical stress in the short term will
cause heave to take place. Undrained soil parameters have been used to estimate the potential
short term movements, which include the “immediate” or elastic movements as a result of the
basement excavation. Drained parameters have been used to provide an estimate of the total
long-term movement.
The elastic analysis requires values of soil stiffness at various levels to calculate
displacements. Values of stiffness for the soils at this site are readily available from published
data and we have used a well-established method to provide our estimates. This relates values
of Eu and E', the drained and undrained stiffness respectively, to values of undrained cohesion,
as described by Padfield and Sharrock3 and Butler4 and more recently by O’Brien and Sharp5.
Relationships of Eu = 500 Cu and E’ = 300 Cu for the cohesive soils and 2000 x SPT ‘N’ for
granular soils have been used to obtain values of Young’s modulus. More recent published
data6 indicates stiffness values of 750 x Cu for the London Clay and a ratio of E’ to Cu of
0.75, but it is considered that the use of the more conservative values provides a sensible
approach for this stage in the design.
3
4
5
6
Padfield CJ and Sharrock MJ (1983) Settlement of structures on clay soils. CIRIA Special Publication 27
Butler FG (1974) Heavily overconsolidated clays: a state of the art review. Proc Conf Settlement of Structures, Cambridge, 531578, Pentech Press, London.
O’Brien AS and Sharp P (2001) Settlement and heave of overconsolidated clays - a simplified non-linear method. Part Two,
Ground Engineering, Nov 2001, 48-53
Burland JB, Standing, JR, and Jardine, FM (2001) Building response to tunnelling, case studies from construction of the Jubilee
Line Extension. CIRIA Special Publication 200
Ref J16116A
Issue No 1
28 July 2016
6
134 Old Street, London EC1V
9BL YPP Ltd
Ground Movement
Assessment Report
The soil parameters used in this assessment are tabulated below.
Stratum
Depth range (m)
[Level range mOD]
Eu (MPa)
E’ (MPa)
Made Ground
G/L to 3.0
17.5
10.5
Hackney Gravel
3.0 to 6.5
50
50
London Clay
6.5 to 25.0
32.5 to 170
19.5 to 51
Lambeth Group
25.0 to 36.0
170 to 250
51 to 75
A rigid boundary for the analysis has been set at a depth of 36 m below existing ground level,
where nearby BGS records indicate that the base of the Lambeth Group is likely to be present.
Given the site investigation didn’t reach the Lambeth Group, strength parameters have been
derived using in-house dataset and engineering judgement.
5.2.2
Results
The proposed excavation of the new basement will result in a net unloading of approximately
75 kN/m². The P-Disp analysis indicates that, by the time the basement construction is
complete, around 8 mm of heave is likely to have taken place at the centre of the proposed
excavation, while around 3 mm to 5 mm of settlement will have occurred at the edges.
An additional 7 mm to 8 mm of long term heave may theoretically occur at the centre of the
proposed excavation following construction while an additional 3 mm of settlement may
occur at the edges of the excavation.
The results of the P-Disp analysis can be used to indicate the likely impact of the proposed
basement construction beyond the site boundaries; about 5 m away from the excavation a total
movement of less than 5 mm is predicted. In addition, movements outside the excavation will
be further constrained to a certain extent by the presence of the new retaining walls.
The basement floor slab will need to be designed to resist the potential heave pressures which
are typically taken to equate to around 30 % of the total unloading pressure.
6.0
DAMAGE ASSESSMENT
In addition to the above assessment of the likely movements that will result from the proposed
development, the neighbouring buildings are considered to be sensitive structures, requiring
Building Damage Assessments, on the basis of the classification given in Table 2.5 of C5801.
All structures are shown on the plan in Section 5.1.2.
6.1
Damage to Neighbouring Structures
The movements resulting from the wall installation phase and the combined retaining wall
installation and basement excavation phases, have been calculated using the X-Disp
modelling software to carry out an assessment of the likely damage to adjacent properties and
the results are summarised for the combined wall installation and basement excavation in the
table below. Where the analysis has indicated that the structure is unlikely to experience
Ref J16116A
Issue No 1
28 July 2016
7
134 Old Street, London EC1V
9BL YPP Ltd
Ground Movement
Assessment Report
damage of higher than Category 0 – Negligible, they have not been included within the table
below.
The potential heave movements predicted by P-Disp have not been included in this
assessment.
Building Damage Assessment
Sensitive Structure
Elevation
Category of Damage*
Structure B
N
Category 1 (Very Slight)
W3
Category 1 (Very Slight)
W4
Category 1 (Very Slight)
E
Category 1 (Very Slight)
W
Category 1 (Very Slight)
Structure C
Structure D
*From Table 2.5 of C5801: Classification of visible damage to walls.
The analysis has predicted that the proposed installation of the retaining walls and excavation
of the proposed basement may generally result in a building damage for sensitive structures of
Category 0 (negligible) and Category 1 (Very Slight), which fall within acceptable limits.
In practice, the underpinning of the existing foundations, installation of the contiguous piled
wall and the subsequent excavation of the proposed basement will be staged processes and
will take place over a number of weeks. This will provide an opportunity for the ground
movements during and immediately after the installation of the retaining walls to be measured
and the data acquired can be fed back into the design and compared with the predicted values.
Such a comparison will allow the ground model to be reviewed and the predicted wall
movements to be reassessed prior to the main excavation taking place so that propping
arrangements can be adjusted if required.
In addition to the above, there is a wealth of experience with respect to the construction of
underpinned retaining walls, that suggests that ground movements should remain typically
within the range of 2 mm to 5 mm following completion of the works and provided that they
are installed by a reputable and experienced contractor in accordance with the guidelines
published by the Association of Specialist Underpinning Contractors 7, which indicates that
the predicted movements represent a conservative assessment of the likely movements.
6.2
Monitoring of Ground Movements
The predictions of ground movement based on the ground movement analysis should be
checked by monitoring of the adjacent properties and structures. The structures to be
monitored during the construction stages should include the neighbouring structures.
Condition surveys of the above existing structures should be carried out before and after the
proposed works.
The precise monitoring strategy will be developed at a later stage and it will be subject to
discussions and agreements with the owners of the adjacent properties and structures.
Contingency measures will be implemented if movements of the adjacent structures exceed
7
Haslam S, O’Connor L (2013) Guidelines on safe and efficient basement construction directly below or near to existing
structures ASUC
Ref J16116A
Issue No 1
28 July 2016
8
134 Old Street, London EC1V
9BL YPP Ltd
Ground Movement
Assessment Report
predefined trigger levels. Both contingency measures and trigger levels will need to be
developed within a future monitoring specification for the works.
Ref J16116A
Issue No 1
28 July 2016
9
134 Old Street, London EC1V
9BL YPP Ltd
7.0
Ground Movement
Assessment Report
CONCLUSIONS
The analysis has predicted that the proposed installation of the retaining walls and excavation
of the proposed basement may generally result in a building damage for sensitive structures of
Category 0 (negligible) and Category 1 (Very Slight), which fall within acceptable limits.
The separate phases of work, including excavation of the proposed basement, will in practice
be separated by a number of weeks during which time construction of permanent supports,
basement slab and retaining wall curing will take place. This will provide an opportunity for
the ground movements during and immediately after retaining wall construction to be
measured and the data acquired can be fed back into the design and compared with the
predicted values. Such a comparison will allow the ground model to be reviewed and the
predicted wall movements to be reassessed prior to the main excavation taking place so that
propping arrangements can be adjusted if required.
Ref J16116A
Issue No 1
28 July 2016
10
134 Old Street, London EC1V 9BL
YPP Ltd
Ground Movement
Assessment Report
APPENDICES
X-DISP ANALYSIS:
Wall Installation
Contour Plots of Vertical Movements and Horizontal Movements
Wall Installation and Basement Excavation combined
Contour Plots of Combined Vertical Movements and Horizontal Movements
P-DISP ANALYSIS
Short Term Movement Contour Plots
Total Movement Contour Plots
Ref J16116A
Issue No 1
28 July 2016
11
GEA LIMITED
(GEOTECHNICAL &ENV ASSOC)
134 Old Street, London, EC1v 9BL
Wall installation
Job No.
Sheet No.
Rev.
J16116
Drg. Ref.
Made by
JD
Date
12-Jul-2016
Checked
Horizontal Displacement Contours: Grid 1 (level -1.000m) Interval 1mm
220.0
<0
0-1
1-2
210.0
2-3
3-4
200.0
4-5
y [m]
190.0
180.0
170.0
160.0
150.0
240.0
280.0
320.0
360.0
Scale x 1:982 y 1:982
x [m]
Program Xdisp Version 19.3.1.35 Copyright © Oasys 1997-2015
G:\CURRENT\16-\J16116\GMA\Xdisp\134 Old St wall installation.xdd
Printed
20-Jul-2016
Page
1
Time 14:24
GEA LIMITED
(GEOTECHNICAL &ENV ASSOC)
134 Old Street, London, EC1v 9BL
Wall installation
Job No.
Sheet No.
Rev.
J16116
Drg. Ref.
Made by
JD
Date
12-Jul-2016
Checked
Vertical Settlement Contours: Grid 1 (level -1.000m) (Interval 1mm)
220.0
<0
0-1
1-2
210.0
2-3
3-4
200.0
4-5
y [m]
190.0
180.0
170.0
160.0
150.0
240.0
280.0
320.0
360.0
Scale x 1:982 y 1:982
x [m]
Program Xdisp Version 19.3.1.35 Copyright © Oasys 1997-2015
G:\CURRENT\16-\J16116\GMA\Xdisp\134 Old St wall installation.xdd
Printed
20-Jul-2016
Page
1
Time 14:24
GEA LIMITED
(GEOTECHNICAL &ENV ASSOC)
134 Old Street, London, EC1v 9BL
Combined
Job No.
Sheet No.
Rev.
J16116
Drg. Ref.
Made by
JD
Date
12-Jul-2016
Checked
Horizontal Displacement Contours: Grid 1 (level -1.000m) Interval 1mm
220.0
<0
0-1
1-2
210.0
2-3
3-4
200.0
4-5
y [m]
190.0
180.0
170.0
160.0
150.0
240.0
280.0
320.0
360.0
Scale x 1:982 y 1:982
x [m]
Program Xdisp Version 19.3.1.35 Copyright © Oasys 1997-2015
G:\CURRENT\16-\J16116\GMA\Xdisp\134 Old St Combined.xdd
Printed
20-Jul-2016
Page
1
Time 14:27
GEA LIMITED
(GEOTECHNICAL &ENV ASSOC)
134 Old Street, London, EC1v 9BL
Combined
Job No.
Sheet No.
Rev.
J16116
Drg. Ref.
Made by
JD
Date
12-Jul-2016
Checked
Vertical Settlement Contours: Grid 1 (level -1.000m) (Interval 1mm)
220.0
<0
0-1
1-2
210.0
2-3
3-4
200.0
4-5
5-6
6-7
y [m]
190.0
7-8
8-9
9 - 10
180.0
10 - 11
11 - 12
170.0
12 - 13
13 - 14
14 - 15
160.0
15 - 16
16 - 17
150.0
240.0
280.0
320.0
360.0
Scale x 1:982 y 1:982
x [m]
Program Xdisp Version 19.3.1.35 Copyright © Oasys 1997-2015
G:\CURRENT\16-\J16116\GMA\Xdisp\134 Old St Combined.xdd
Printed
20-Jul-2016
Page
1
Time 14:28
GEA LIMITED
(GEOTECHNICAL &ENV ASSOC)
134 Old Street, London, EC1V 9BL
Short term heave
Job No.
Sheet No.
Rev.
J16116
Drg. Ref.
Made by
JD
Date
Checked
Settlement Contours : Grid 1 at -4.0000m
60.00
-8.000 : -7.00
-7.000 : -6.00
-6.000 : -5.00
-5.000 : -4.00
-4.000 : -3.00
-3.000 : -2.00
50.00
-2.000 : -1.00
-1.000 : 0
0 : 1.000
40.00
Y [m]
30.00
20.00
10.00
.0
-10.00
10.00
Scale x 1:448 y 1:448
Contour Interval: 1mm
Program Pdisp Version 19.3.0.4
30.00
50.00
X [m]
Copyright © Oasys 1997-2015
Printed
20-Jul-2016
Page
1
Time 14:47
GEA LIMITED
(GEOTECHNICAL &ENV ASSOC)
134 Old Street, London, EC1V 9BL
Total Heave
Job No.
Sheet No.
Rev.
J16116
Drg. Ref.
Made by
JD
Date
Checked
Settlement Contours : Grid 1 at -4.0000m
60.00
-16.00 : -15.0
-15.00 : -14.0
-14.00 : -13.0
-13.00 : -12.0
-12.00 : -11.0
-11.00 : -10.0
50.00
-10.00 : -9.00
-9.000 : -8.00
-8.000 : -7.00
-7.000 : -6.00
-6.000 : -5.00
40.00
-5.000 : -4.00
-4.000 : -3.00
-3.000 : -2.00
-2.000 : -1.00
-1.000 : 0
Y [m]
30.00
20.00
10.00
.0
-10.00
10.00
Scale x 1:448 y 1:448
Contour Interval: 1mm
Program Pdisp Version 19.3.0.4
30.00
50.00
X [m]
Copyright © Oasys 1997-2015
Printed
20-Jul-2016
Page
1
Time 14:51
Geotechnical & Environmental Associates (GEA) is an engineer‐led and client‐
focused independent specialist providing a complete range of geotechnical and contaminated land investigation, analytical and consultancy services to the property and construction industries. We have offices at Widbury Barn Widbury Hill Ware Hertfordshire SG12 7QE tel 01727 824666 mail@gea‐ltd.co.uk Church Farm Gotham Road Kingston on Soar Notts NG11 0DE tel 01509 674888 midlands@gea‐ltd.co.uk Enquiries can also be made on‐line at www.gea‐ltd.co.uk where information can be found on all of the services that we offer.