20100810-RonanLeroy.pdf

10th August 2010

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Australian Geomechanics Society Australasian Tunnelling Society

Diaphragm Walls - Design and Construction

Diaphragm Wall- Principles and Applications- Le Havre Port 2000- The Sail

AGS-ATS Perth Aug 2010

D-Wall : retaining, cut off, foundation


Diaphragm Wall – construction principles








Diaphragm Wall – Equipment








Application: retaining structure


Application : TBM shaft, metro station,..


Application : cut & cover tunnel, ramp,..


Application : cut off


Application : UG tanks, water station,..


Application : car park, basement,..


Diaphragm wall – indicative figures

Geometry Widths : 0.5 to 1.5mDepths : 25 to 45 m are common (max 150 m)Verticality: 1% is common

Material Tremie mix concrete, 20 mm slump Steel: 70 to 200 kg/m3

PropertiesMoments: 1200 kN/m for 0,8 m wall; 4 000 kN.m for 1,5 m wallPermeability: 10 E-7 m/s to 10 E-9 m/s


PORT AUTONOME DU HAVRE

TheThe site on site on 10/09/200110/09/2001

Le Havre : Design


Plan View

Le Havre : Design


A reinforced concrete

front wall.

Sheet piled as rear wall

Tie – rods between the

walls.

Capping beam with bollards and

fenders

Le Havre : Design


Le Havre : Design

Quay : 1600 lm Diaphragm Wall

42 m deep, 1,2 m wide, 150 kg/m3

67 000 m2, 80 000 m3 concrete, 12 000 t steel

Dewatering 180 wells, 1900 m3/dyAnchors 5,600TSheet Piles 1,000TDredging 11,000,000 m3Earthworks 3,000,000 m3Civil Works 30,000 m3Bored piles 500 nr, 17ml, 520 mm


PHASE 1Preparation of working platform

Construction of Guide WallsInstallation of Well Points

Le Havre: phase 1


Le Havre: phase 1


PHASE 2Construction of Diaphragm Walls

Le Havre: phase 2


Le Havre: phase 1



Le Havre:


PHASE 3Removal of the guide walls

Excavation in front of the wall during dewatering

Le Havre: phase 3


Le Havre: phase 3


PHASE 4Cast capping beam and dock buffers

Le Havre: phase 4


Le Havre: phase 4


PHASE 5Earthwork excavation behind wall during

dewatering

Le Havre: phase 5


Le Havre: phase 5


PHASE 6Installation of sheet pile curtain

Lay lower layer of anchors

Le Havre: phase 6


Le Havre: phase 6


Le Havre: phase 6


PHASE 6Backfill to level upper anchor layer and

lay upper layer of anchors

Le Havre: phase 6


Le Havre: phase 6


Sheet pilesSheet piles

DWall 1,20 mDWall 1,20 m

FF -7.50 Tie backsTie backs

Sea side

Land side

Le Havre: phase 6


PHASE 6Backfill to formation level, construct all civil

works, install bumpers, stop dewatering, dredging, crane rail foundations and rails.

Le Havre: phase 6


Le Havre: phase 6


Le Havre: phase 6


Le Havre: phase 6


Le Havre: Now


Now in Cotonou


Now in Cotonou


The Sail @ Marina bay

Owner: City Dvpt /American

International

Engineer: Meinhardt

Main Contractor: Dragages


9,090.9 sqmSite Area

118,182 sqmPermissible GFA

No of floors: 70Typical Floor GFA: 1,026 sqmHeight: 242m

Tower 1

No of floors: 63Typical Floor GFA: 746 sqmHeight: 202m

Tower 2

No of floors: 7Typical Floor Plate: 3,726 sqm

Podium

The Sail@ Marina Bay


Site Condition (1995)

The Sail@ Marina Bay


BH-5BH-5BH-5

Tower 2

Tower 1Expected Fort Canning

Boulder Bed

Existing Buried Pier

8m Canal

CST

The Sail: IssuesSite specificities• Thick marine clay (up to 35m

of Kallang formation = very soft to soft)

• Fort Canning Boulder Bed• UG obstacle = old pier below

the tower• MTR running tunnel & CS

excavation along the siteProject issues• To control movement of

MRT tunnels & CS Tunnel is a REAL must

• Very tight program = 6 months for foundations + excavation


The Sail : Design Philosophy

Alternative solution by SB : Circular structure design• naturally self stabilising and VERY rigid • excavation possible with no jet grouting and no struting+ staggered equipments working units

safe solution in term of deflection/displacement as well as program


The Sail: Design


The Sail : Design 3D Finite Elements Design

• Predicted wall deflection is about 15mm• Basal heave FoS ~2.21• Movement of barrettes due to basal heave ~ 7mm• Distribution of forces in the Y panel considered

• Dissymmetrical loading due to soil variation considered• Dissymmetrical loading due GWT variation considered• Maximum differential excavation of about 0.5m allowed


The Sail : Foundation PlanTemporaryRetentionSystem

T1

3rd

MRT R

eser

ved

Line

TemporaryD-W all

Perimeter • 3 symmetrical 32.2m diam circular Dwalls, • 29 m deep, 220 ml long• 800 mm thick• with cross walls.

Barettes • 79 Nos. of 1,2 x 2,8• up to 67 m deep, incl 20 m in SPT>100• all toes grouted ;


The Sail: Works


The Sail: Works


Ultimate Load test

• 1 ultimate load test with smaller barrette 600 x 2400 @ 2.5 WL carried out – 2700 TONS

• 2 working barrette tests on 1000 x 2800 barrette carried out with settlement <15mm @ 1.5 WL –max 3660 TONS

• All the tests were done using kentledge method


The Sail: Today


Isle of Grain


Conclusion

Le Havre Port 2000Site opportunity : shallow waterIssue : optimisation (phasage/dewatering/quantities/..)

The SailProject constraint: tight program, neighb. structuresIssue : design, execution

Ronan Le [email protected]

20100810-RonanLeroy.pdf

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