!

Petitioners' property

0 375 750 1,125 1,500

Metres

I

Doc Number: LWM-HS2-HY-MAP-030-000607-P02 Date: 23/02/15

Scale at A3: 1:35,000

³A ³B ³C ³D ³E ³F ³G ³H ³I ³J

³A ³B ³C ³D ³E ³F ³G ³H ³I ³J

³10

³9

³8

³7

³6

³5

³4

³3

³2

³1

³10

³9

³8

³7

³6

³5

³4

³3

³2

³1

HS2 Ltd accept no responsibility for any circumstances, whicharise from the reproduction of this map after alteration,amendment or abbreviation or if it is issued in part or issuedincomplete in any way.

High Speed TwoCountry North Petitioner Location Plan

Reference Drawing

!

!

!

!

!

LONDON

BIRMINGHAM

LEEDSMANCHESTER

Petition numberHS2-HS2-HY-PET-001056

Petitioner

LegendPhase Two Western Leg proposed alignment July 2013

At GradeCutting

EmbankmentViaduct

! Petitioners' property

SC-02-3631Malcolm and Margot Pritchard

Registered in England. Registration number 06791686. Registered off ice: One Canada Square, London E14 5AB.

This material was last updated on [date] and may not be copied,distributed, sold or published without the formal permissionof Land Registry and Ordnance Survey. Only an official copy of atitle p lan or reg ister obtained from the Land Registry may be used forlegal or o ther official purposes. © Crown Copyright Ordnance Survey.This is not a copy of a title plan issued by LR.

© Crown copyright and database rights 2015.Ordnance Survey Licence Number 100049190.

P6184 HOC/01056/0002

Tunnelling-induced ground movements and their effects

Professor Robert Mair CBE FREng FICE FRS

Cambridge University

June 2015

R1246 (1) HOC/10050/0002

2/46

Outline of Presentation

• Background

• Sources of ground movement

• Settlement assessment

• Additional considerations for listed buildings

• Mitigation measures

• Pile-tunnel interactions

• Utilities

• Conclusions

R1246 (2) HOC/10050/0003

3/46

Background

• HS2 Route – Tunnelled Section (London

Area)

• Ground & Groundwater Conditions

R1246 (3) HOC/10050/0004

4/46

Background

West Ruislip Portal to Old Oak Common

R1246 (4) HOC/10050/0005

5/46

Ground Conditions

Chalk

Lambeth Group

London Clay

Thanet Sand

Tunnel Alignment

100m4km

West Ruislip Portal

Old Oak Common

R1246 (5) HOC/10050/0006

6/46

Lambeth Group Example (HS1, Stratford Box)

Lambeth Group

West Ruislip Portal

Old Oak Common

R1246 (6) HOC/10050/0007

7/46

London Clay Example – Heathrow T5

West Ruislip Portal Old Oak Common

London Clay

R1246 (7) HOC/10050/0008

8/46

Tunnel Alignment

West Ruislip Portal

Old Oak Common

100m ATD

Groundwater level in the deep aquifer

Groundwater Level in the Deep Aquifer

R1246 (8) HOC/10050/0009

9/46

Sources of Ground Movement

• Why Settlement Occurs

• Tunnelling Methods

• Volume Loss & Patterns of Settlement

• Measured Volume Losses

• Portals and Shafts

• Long Term Settlement

R1246 (9) HOC/10050/0010

10/46

• HS2 requires excavation of ground to form the tunnels, shafts and portals

• The ground around these excavations requires structural support - linings for tunnels and shafts, and walls for portals

• Excavation and installation of support to the ground inevitably produces small, controlled ground movements

• The ground movements cause settlement of the ground surface and buildings and utilities

Sources of Ground Movement Why Settlement Occurs

R1246 (10) HOC/10050/0011

1

2

3

4

5

67

8

1. Tunnel face

2. Cutting wheel

3. Excavation chamber

4. Pressure bulkhead

5. Thrust cylinders

6. Screw conveyor

7. Segment erector 8. Segmental Lining

7

1. Tunnel face

2. Cutting wheel

3. Excavation chamber

4. Pressure bulkhead

5. Thrust cylinders

6. Screw conveyor

7. Segment erector8. Segmental Lining

Tunnelling Methods:– Earth Pressure Balance Machine (EPBM)

R1246 (11) HOC/10050/0012

1

2

3

4

5

67

8

1. Tunnel face

2. Cutting wheel

3. Excavation chamber

4. Pressure bulkhead

5. Thrust cylinders

6. Screw conveyor

7. Segment erector 8. Segmental Lining

7

1. Tunnel face

2. Cutting wheel

3. Excavation chamber

4. Pressure bulkhead

5. Thrust cylinders

6. Screw conveyor

7. Segment erector8. Segmental Lining

Tunnelling Methods:– Earth Pressure Balance Machine (EPBM)

R1246 (12) HOC/10050/0013

Crossrail Bond Street Station - Construction of Sprayed Concrete Lining (SCL) Platform Tunnel

12m outer diameter

Pilot tunnel (5m diameter)

Monitoring targets

R1246 (13) HOC/10050/0014

SCL – Typical Excavation Sequence with Pilot Tunnel

Step 2: enlarge in 3 stages

Step 1: excavate pilot tunnel

1

1

2a

2a 2a

2b

2b

2c

2c

Top Heading

Bench

Invert

R1246 (14) HOC/10050/0015

14/46

Extent ofsettlement trough

Sources of Ground Movement Developing Settlement Trough

R1246 (15) HOC/10050/0016

15/46

Sources of Ground MovementLongitudinal Settlement Trough

R1246 (16) HOC/10050/0017

sma

x

Tunnel

smax

(B) tunnelVolume

(A) trough settlement Volume %) (VL, loss Volume

Sources of Ground Movement - Volume Loss

Transverse settlement trough

B Typical EPBM VL is consistently < 1%

Typical SCL VL is consistently < 1.5%

A

Settlement

Point of inflection

R1246 (17) HOC/10050/0018

0

10

20

30

40

50

60

70

80

90

100

-40 -30 -20 -10 0 10 20 30 40

Distance (m)

Set

tlem

ent

(mm

)

0

5

10

15

20

25

30

35

De

pth

(m)

Tunnels

Settlement

Effect of Tunnel Depth - Schematic

Flatter slopes

R1246 (18) HOC/10050/0019

18/46

0

10

20

30

40

50

60

70

80

90

100

-40 -30 -20 -10 0 10 20 30 40

Distance (m)

Set

tlem

ent

(mm

)

0

5

10

15

20

25

30

35

De

pth

(m)

Tunnels

Settlement

Effect of Tunnel Diameter - Schematic

R1246 (19) HOC/10050/0020

19/46

Measured Volume Losses in Various Soil Strata

R1246 (20) HOC/10050/0021

20/46

West Portal

Stratford BoxMade Ground &

Terrace Gravel

Groundwater table in upper aquifer

Groundwater table in lower aquifer

London Clay

Woolwich & Reading Beds

Upnor Formation

Thanet Sand

Chalk

Chainage (m)

Ele

vati

on

(m)

40

30

20

10

0

-10

-20

-30

-40

2000 3000 4000 5000 6000 7000 8000 9000

Earth Pressure Balance Machine (EPBM) - CTRL Contract 220 Geology

Lambeth Group

R1246 (21) HOC/10050/0022

21/46

0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1000 3000 5000 7000 9000

Chainage (m)

Vo

lum

e lo

ss (

%)

Stratford BoxWest Portal

Volume loss for Up-Line EPBM tunnel CTRL Contract 220 (Wongsaroj et al, 2005)

Typical EPBM VL consistently < 1%

WRB+UF

TS+ Upnor

Formation (UF)

Thanet Sand

(TS)

TS+Chalk

Woolwich and

Reading Beds

(WRB)

WRB+HF

WRB+HF+LC

London Clay

(LC)

R1246 (22) HOC/10050/0023

22/46

Case HistoriesVolume Loss in SCL Projects in London Clay

Project and SCL works in London Clay Volume loss measured at

end of construction

Redcross Way Trial 1.0%Jubilee Line Extension Project, Waterloo Station 1.0% to 1.5%Heathrow Express Trial Tunnel 1.05% to 1.37%Heathrow Express Main Works - T4 Station Platform Tunnels 0.6% to 0.9%

Heathrow Express Baggage Transfer Tunnel 0.5%Kings Cross Station Redevelopment Phase II 0.65% to 1.25%Crossrail 1) Whitechapel Station Platform2) Liverpool St Station Platform3) Stepney Green Caverns

1.22% - 1.29%0.92% - 1.41%

1.25%

Typical SCL volume loss consistently less than 1.5%R1246 (23) HOC/10050/0024

• Excavation of portals and shafts cause ground movements

• Extent of settlement depends on shape and depth of excavation (H)

props

Portals and Shafts

Wall

H

In the range of H to 2.5H

Magnitude of settlement is related to dimensions of excavation and stiffness of the props and walls

Settlement

R1246 (24) HOC/10050/0025

• The settlements described previously are immediate - occurring during construction

• In the long term, further settlements could develop -these occur as a result of slow drainage of pore water from the soil into the new tunnel

• Long term movements occur very slowly and result in much wider and flatter settlement troughs

• Long term settlements are not usually damaging to structures and utilities

Long Term Settlement

R1246 (25) HOC/10050/0026

25/46

Settlement Assessment

• Settlement Assessment Process

• Definition of Risk Categories

• Basis of HS2 Assessments

• Examples from Crossrail & Jubilee Line

Extension

• Conclusions for HS2

R1246 (26) HOC/10050/0027

26/46

• Assessment of the risk of damage to assets is carried out using a screening process

• The HS2 process is based on that used successfully on Crossrail, Jubilee Line Extension, Channel Tunnel Rail Link and many other projects worldwide

• The approach is intentionally conservative

• Protective measures will be provided where predicted effects are above acceptable limits

Assessment of Effects of Settlement

R1246 (27) HOC/10050/0028

27/46

Phase 1: simple criteria based on settlement and slope to eliminate buildings subjected to minimal effects.

Phase 2: conservative assessment of potential damage to buildings through distortions based on ‘greenfield’ settlements.

Phase 3: detailed assessment to determine risk of potential damage and design of protective measures if necessary

Settlement Assessment – 3 Phases

Experience has confirmed that results of Phase 2 are conservative.

R1246 (28) HOC/10050/0029

28/46

Aesthetic significance only

Damage Risk

Category

Degree of Damage

Description of typical damage

Limiting tensile strain

(%)

0 Negligible Hairline cracks less than about 0.1mm 0-0.05

1 Very Slight

Fine cracks treatable during decoration generally restricted to internal wall

finishes. Typical crack widths up to 1 mm

0.05-0.075

2 Slight

Cracks easily filled. Re-decoration probably required. Cracks visible

externally and repainting required. Doors and windows may stick slightly.

Typical crack width up to 5 mm

0.075-0.15

Definition of Risk Categories (Building Research Establishment)

R1246 (29) HOC/10050/0030

29/46

Damage Risk

Category

Degree of Damage

Description of typical damage

Limiting tensile strain

(%)

3 Moderate

Cracks may require patching. Re-pointing and replacement of parts of external brickwork. Doors / windows sticking. Utility service interruption.

Crack widths 5 to 15mm

0.15-0.30

4/5

Severe /

Very

Severe

Major structural damage requiring extensive repair. Floors slope and wall

bulge noticeably. Loss of bearing in beams. Utility disruption. Crack widths

15 to 25mm

>0.30

Potential impact on function or structural damage

Definition of Risk Categories (Building Research Establishment)

R1246 (30) HOC/10050/0031

30/46

EBP Machines

Channel Tunnel Rail Link: 0.5 – 1.0%

Jubilee Line Extension: 0.5 – 1.0%

DLR Woolwich Extension: 0.5 – 1.0%

Crossrail: 0.2 – 1.0%

Sprayed Concrete Lining (SCL)

JLEP, HEX, KX & Crossrail: 0.6 – 1.5%

TunnelTunnel

smax

TunnelTunnelTunnelTunnelTunnelTunnel

smax

tunnel Volumetrough settlement Volume (%) loss Volume

Tunnels: Summary of Typical Volume Loss Experience and Basis of HS2 assessments

HS2 assessments based on:

1% for EPBM running tunnels 1.5% for SCL tunnels

R1246 (31) HOC/10050/0032

31/46

SAGGING HOGGING

Compression Extension

Assessment – Deformation Types

R1246 (32) HOC/10050/0033

32/46

hogging zone sagging zone

building

tunnel

Deformation of Building above a Tunnel

Calculate the maximum tensile strain to determine damage risk category

i

Point of

inflection

R1246 (33) HOC/10050/0034

33/46

Girdlers' Hall

Vehi

cula

rTu

rnta

ble

PH

PO

Telephone Exchange

Vehi

cula

rTu

rnta

ble

MO

OR

LAN

E

Fire Station

Coroners Ct and CorpnOffices

Milton Court

WB

ROPEMAKER STREET

Tenter HousePH(below)

NEW UNION STREET

MoorgateStation

(LondonTransport)

PH

FOR

E ST

REE

T

AVENUE

MoorHouse

BM 13.25m

ArmourersHall

Austral House

LB

CO

LEM

AN S

TREE

T

BankUnd C

OP

THA

LL A

VEN

UE

12.5m

LONDON WALL

Albi

on

Salisbury House

Bank

Lond

on G

uild

hall

Uni

vers

ity

12.8m

Gate(site of)

13.4m

PH

PH

Bank

Underground RailwayMO

OR

GAT

ELB

Bank

War

d Bd

y

Def

MOOR PLACE

Bank

14.0m

Moo

rfiel

ds H

ouse

City and County of the City of London

14.3m

Finsbury Court

FIN

SBU

RY

PAVE

MEN

T

LB

City Gate House

LACKINGTON STREET

DO

MIN

ION

STR

EET

SOUTH PLACE

13.9m

SOU

TH P

LAC

E M

EWS

River Plate House

PH

FINSBURY CIRCUS

BandstandSD

D Fn

Bowling Green

LB

FINSBURYCIRCUS

CIR

CU

S PL

ACE

Bank

Def12.5m

Ward Bdy

PH

Bank

Postern(site of)

BLOMFI

ELD S

TREET

CR

London WallBuildings

ELDON STREET13.1m

St M

ary

Moo

rfiel

dsCh

urch

WIL

SON

STR

EET

14.7m

Def

19

20

11

14

9

16

21

45

119

8081

34

7367

63

48 to 54

56 to 60

64 62

42

41

25

6465

2

53

46

47

12

1110

98

23

4

2

1

2

25

5

1514

13

3

5

4

21

18

16

7 to 11

94

110 to 120

16

12 to 13

26 to 31

18 to 25

14

7 to 9

6

54

32

1

2 to 12

1513

39 to 45

4

14

10 to 13

137

86

42

118 118a 8385

87

72

84

150 to 168

3

CITY AND EAST GL ASLY CONST

BIS

HO

PSGATE W

ARD

BROAD STREET WARDCOLEMAN STREET WARD

SH

OR

EDITC

H

DrillTower

1 to 13

7

101

14.4

m

MIL

TON

STR

EET

Bank

45

Car Park

1416

20

24

103

to 1

09

12

91to

95

MO

OR

FIEL

DS

1

25

Whitecross

141

City

& C

ount

y of

the

City

of L

ondo

n Bd

y

21

TCBs

3

Fins

bury

Ave

nue

FIN

SBU

RY

AVEN

UE

Moorfields Highwalk

Moorfields

Hig

hwal

k

Keats Place

Moor

85Und

43

127-

131

55

Brita

nnic

Hig

hwal

k

Milton Court Highwalk

155

Plac

e

49

28

3.5

Bank

Bank

Place 2

19 to 24

Def

Willo

ughb

y H

ighw

alk

Brita

nnic

Hig

hwal

k

31

30

20

31

Britannic House

115

125

15

New Broad St

4216

1963 to 54

30 to 20

59

60

Broad

Street

Plac

e

16 to24

TCBs

29

PH

Finsbury CircusHouse

14

TCBs

TCPs

TCBsTCP

CR

CR

City

& C

ount

y of

the

City

of L

ondo

nBo

ro C

onst

,GL

Asly

Con

st &

LB

Bdy

Boro Const,GL Asly Const & LB Bdy

CR

Ward Bdy

Boro

Con

st, G

L As

ly &

LB

Bdy

War

d Bd

y War

d Bd

y

FB

(Sch

ool o

f Bus

ines

s St

udie

s)

38

70

3 to 6

17

1

36

PC

TCB

TCB

Posts

12

1

13

7

35

Post

s

Posts

City Point

CITIES OF LONDON AND WESTMINSTER BORO CONST

BISH

OPSG

ATE W

ARD

CR

CR

Def

White HorseYard

GuildhallChambers

BPs

Def

Bank

Great Swan Alley

Nun Court

13.1m

LBGREAT SWAN ALLEY

Institute ofChartered Accountants

MO

OR

GA

TE P

LAC

E

Bank

Bank

Bank

Def

LANGTHORN COURT

CO

PTH

ALL

AVEN

UE

FW

CW

BPs

Dra

pers

Gardens

Bank

BankGREAT WINCHESTER STREET

LONDON WALL

Carpenters' Hall

BM 13.10m

Und

216

74

64 to 66

3

5

2511

8

610

1214

16

24

1

72

25

24

2315

21

WARDBISHOPSGATE

41

35 to

39

42 3836

4044

46

67

CITY AND COUNTY OF THE CITY OF LONDONCITIES OF LONDON AND WESTMINSTER BORO CONST

Def

6

COLEMAN STREET WARD

CW

LON

DO

N EE

R

Wall

Bank 51

53

Coleman Street Bldgs

30 to 34

Bank

30 to 20

9 to 19

5 to 7

19

ElSubSta

4

63

Bank

Bank Bank

21

Piercy House

Bank

9

3

75

1Woolgate Exchange

Ward Bdy

20

Def

FW Capel House

All Hallows on the WallChurch

LONDON WALL

BM 13.82m

BP

Broad Street HouseUnd

13.4m

WORMWOOD STREET14.4m

PH

Tennis Court

Bishopsgate Churchyard

St Botolph withoutBishopsgate Church

FnBPs

FW

83

52 to 57

27 to 34

7

26

105

to 1

07

CITY AND COUNTY OF THE CITY OF LONDON

FB

45

8

TCB's

82

87 to

91

6364

BostonHouse

25

Bank

75

Bank

215

109 22 to24

16 to 24

6

15

76 to

80

54 to 62

55

69

7073

74

17

1819

2021

22 2324

2627

2829

30

12

25

678101112

13 1416 17 18 19 20 22 24

2326

25

32

33

86

4

18

19

2037

31 to 35

29

13

17

SUN STREET

13.3m

Alderman's Walk

Church

14.4m

LB(LRT)

PostsEl Sub Sta

St B

otol

ph's

Chu

rch

Hal

l

LB

(site of)

Petty France

NEW BROAD STREET

OLD

BR

OAD

STR

EET

AVENUEBROAD STREET

SL SL

SBPH

BLOMFI

ELD S

T

LB

Liverpool Street Station

BISHOPSGATECHURCH YARD

CITY AND COUNTY OF THE CITY OF LONDON

CO

LEM

AN S

TRE

ET W

AR

DCourt

White HartAldermansHouse

FinsburyAvenue

3

FB

LIVERPOOL STREET

Turntable

Site of

ofSt Mary of Bethlehem

(Founded AD 1247)

19

6

4

8

10

12

Liverpool St Station

Subway

Priory and Hospital

The Arcade

ELDON12.7m

12.8m

1

War

d Bdy

CR

Broadgate

BroadgateCircle

Arena

BI S

HO

PSG

ATE

WAR

D

Broad Lane

12

3

Octagon Arcade

STREET

TCPs

15

81 to

91

New Broad StreetHouse

HouseSwedbank

42

City &

Cou

nty of

the C

ity of

Lond

on

1

Ice Rink

PH

SUN

STR

EET

PASS

AGE

100

(below)

PostsPosts

Boro C

onst,

GL A

sly C

onst

& LB Bdy

50

21

11

3

1

2631

30

32

3334

3536

37

27

Exchange Place

2

Posts

GR

EATE

R L

ON

DO

N

Eliminated at Phase 1

Eliminated at Phase 2

Settlement contours in millimetres

KEY

Proceed to Phase 3

Example from Crossrail - Phase 2 Assessment Results – Liverpool St Station

EPBM running tunnels usually do not cause significant damageR1246 (34) HOC/10050/0035

34/46

F7

F8

G7

G8

ARCH 242

ARCH 243

ARCH 245ARCH 244

ARCH 241

ARCH 240ARC

H 239

DOOR

AirShaft

El Sub Sta

Shel

ters

3.6m

13 to 65

8

Bank

Eliza

beth

Hou

se

Bank

PH

SL

67 69

Bank

LEAKE STREET

Shel

ter

Shel

ter

CHICHELEY STREET

75 to 79

AirShaft

El Sub Sta

Shel

ters

3.6m

13 to 65

10

8

BM 4.20m

BELV

EDER

E R

OAD

Shell Centre

Bank

Eliza

beth

Hou

se

Bank3.7m

YORK

RO

AD

Jubilee

4.0m

Slop

ing

mas

onry

PH

3.7m

SL

0m 50m 100m

Eliza

beth

House

Shell Centre

WaterlooInternationalTerminal

Case History (JLE)Elizabeth House

R1246 (35) HOC/10050/0036

35/46

-70

-60

-50

-40

-30

-20

-10

0

0 10 20 30 40 50 60 70 80 90 100Distance (m)

Se

ttle

me

nt

(mm

)

Phase 2 Assessment (2%)

Phase 3 Prediction

Observed (building)

Elizabeth House (JLE)Comparison of Observations to Predictions

The Phase 2 assessment is intentionally conservative

No damage observed in Elizabeth House due

to tunnelling

R1246 (36) HOC/10050/0037

36/46

• A conservative and internationally accepted process is used to assess the risk of excavation-induced damage to buildings by the HS2 Project

• For buildings affected by the EPBM tunnelling, the potential damage category is Negligible to Slight (i.e. Category 0 to 2)

• For some buildings close to shallow SCL tunnels, shafts and portals the potential damage category can be Slight, occasionally Moderate (i.e. Category 2 to 3)

Conclusions for HS2London Area

R1246 (37) HOC/10050/0038

37/46

Additional Considerations for Listed Buildings

• All listed buildings within the 10mm contour are

automatically subject to a Phase 3 assessment.

• Additional considerations are taken into account

for listed buildings, allowing for:

i. Structural condition;

ii. Structural sensitivity, and

iii. Sensitivity of heritage features

R1246 (38) HOC/10050/0039

38/46

Additional Considerations for Listed Buildings

Score

Criteria

Sensitivity of the structure toground movements and

interaction with adjacentbuildings

Sensitivity to movement of particularfeatures within the building

0

Masonry building with lime mortarnot surrounded by other buildings.Uniform facades with no particularlarge openings.

No particular sensitive features

1

Buildings of delicate structural formor buildings sandwiched betweenmodern framed buildings which aremuch stiffer, perhaps with one ormore significant openings.

Brittle finishes, e.g. faience or tight-jointedstonework, which are susceptible to smallmovements and difficult to repair.

2

Buildings which, by their structuralform, will tend to concentrate alltheir movements in one location.

Finishes which if damaged will have asignificant effect on the heritage of thebuilding, e.g. cracks through frescos.

Increasing vulnerability

R1246 (39) HOC/10050/0040

39/46

Mitigation Measures

• General

• Compensation Grouting

• Big Ben Case History

R1246 (40) HOC/10050/0041

40/46

Mitigation Measures

• Industry best practice during construction,

including comprehensive monitoring

• Good control of the EPBM and good SCL

construction - minimising volume losses

• If ground movements are still excessive, other

measures include strengthening, underpinning,

jacking or compensation grouting

R1246 (41) HOC/10050/0042

R1246 (42) HOC/10050/0043

R1246 (43) HOC/10050/0044

R1246 (44) HOC/10050/0045

42/46

Big Ben Clock TowerJLE Westminster Station Under Construction

R1246 (45) HOC/10050/0046

43/46

Big Ben & Westminster Station (JLEP)Big Ben & Westminster Station (JLEP)

H = 55m

D

HΔ

= Tilt

31m

R1246 (46) HOC/10050/0047

44/46

Big Ben & Westminster Station (JLEP)

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Big Ben

Big Ben & Westminster Station (JLEP)Plan Layouts of Grout Tube Arrays

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-10

0

10

20

30

40

Tilt

of

Clo

ck

To

we

r (m

m/5

5m

)

Nov-94 Nov-95 Nov-96 Nov-97 Nov-98 Nov-99 Nov-2000

Grouting Episodes

9 13 16 22 25 31 35 39

WB EB WB EB

Tunnel Progress:Pilots Enlargements

Start ofGrouting

Box ExcavationProgress [m]:

ConstructionControlRange

Optical Plumb

Control of tilt of Big Ben Clock Tower by compensation grouting

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Pile-Tunnel Interactions

• Examples for buildings

• Examples for piled bridges

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Crossrail – Kempton Court

• Residential Flats

Constructed in 1996, Load bearing masonry

No basement – 4 storeys

Piled

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Crossrail – Kempton Court• Bored Piles

o Pile cutting necessary for tunnel enlargement

o Most piles within 4 m of tunnel crown

o 350 mm Diameter Piles ~ 16 m length

o 10.7m Diameter Platform Tunnels with 6.3m diameter Pilot Tunnels

EB Tunnel

WB Tunnel

~+87.5 mATD

~110 - 111 mATD

+92.0mATD

~+112.0 mATD

+98.0mATD

ToeLevels

SuperficialDeposits

River TerraceGravels

London Clay

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Crossrail – Kempton Court

−30 −20 −10 0 10 20−40

0

−10

−20

−30

Dis

pla

cem

ent

(mm

)

Perpendicular Distance from PTW (m)

20 30 40 50 60

GF 07

Greenfield

Section

KC 04

Building

Section

Perpendicular Distance from PTE (m)

D

D

A

A

BB

A A

o Building settlements very similar to `Greenfield’ surface settlements

o Building settlements were tolerable

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Crossrail Whitechapel Station -Swanlea School

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Case Histories – HS1, London (bridges)

• Renwick Road (end-bearing piles in gravel), Jacobsz et al (2005)

Driven piles

1% Volume Loss

Piles settled similarly to ‘greenfield’ settlements at pile toe

London Clay

8m diameter tunnels

Terrace Gravels

Made ground

Alluvium, peat

15.5m 42m

Railway lines

PropDriven piles

Upline Downline

Bridge deck

South North

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Case Histories – HS1, London (bridges)

• A406 Viaduct (friction piles), Jacobsz et al (2005)

Low Volume Loss ~ 0.3%

Pile settled similarly to `greenfield’ surface settlements

Pier 6South Pier 8Pier 7

38m 38m

Made ground

Terrace Gravels London Clay

Harwich silt & clay

Lambeth Group

Upnor

Thanet Sands

Railway lines

Boredpiles

North

Zone of influence

Downline Upline

Upper Chalk8m diameter tunnels

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Pile-Tunnel Interactions -Conclusions

• On HS1 and Crossrail new tunnels were

successfully constructed beneath and through

existing piles

• The settlement of the buildings and bridges

were acceptable

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Utilities

• Similar to buildings, a risk-based, damage

assessment process will be adopted for key

utilities potentially affected by HS2

• These utility assessments will be undertaken in

full consultation with the utility providers.

• Mitigation and monitoring measures (if

necessary) will be developed with the utility

providers.

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Conclusions

• There is considerable experience in UK from Crossrail, Jubilee Line Extension, HS1 and many utility tunnels – very little building damage occurred

• A conservative, internationally recognised methodology for the assessment of the risk of damage to buildings is being used

• Proven and effective protective measures are available - these will ensure that the planned works can be undertaken without significant settlement impacts

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References

DoT (2013) IMPACTS OF TUNNELS IN THE UK Non-technical summary, August 2013

HS2 (2013) - Impacts of tunnels in the UK, May 2013

C3: Ground Settlement

Mair (2009) What’s going on underground? Tunnelling into the future. Royal Society public lecture (video) https://royalsociety.org/events/2009/underground-tunnelling/

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