high speed two: engine for growth - … (19) hoc/10050/0020. 19/46 measured volume losses in various...
TRANSCRIPT
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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
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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
!
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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
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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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