Commend, Mellal, Geiser – 08.2007 Z_Soil Day 2007 Lausanne, 27th August 2007 Numerical Simulation of Earthworks and Retaining System for an Excavation.

Commend, Mellal, Geiser – 08.2007

Z_Soil Day 2007Lausanne, 27th August 2007

Numerical Simulation of Earthworks and Retaining System for an Excavation

F. Geiser and S. CommendGeoMod ing. conseils SA



Introduction

• Offices and commercial building

• Lausanne region

• 120 x 35(max) x 9.3 m

Numerical modelling: 3D numerical simulation (Z_Soil)30’000 continuum elements



Slurry wall

Geometry: structural elements



Hydrogeotechnical conditions

9.3 m

8.0 m

3.5 mRemblai

Glacio-sableux

Glacio-argileux mou

Fluvio-glaciaire

Glacio-argileux

Moraine

412.7 msm = 0.0

Molasse imperméable Puits de décharge



Excavation stages

Piles

T = 0. Etat initial



Piles realisation



Slurry wall realisation



Excavation stages

T = 1. Excavation globale jusqu’à -3.0 m



Excavation stages

T = 2. Excavation zone A à -7.0 m, puis étayage à -2.5 m

zone A





Excavation stages

T = 3. Excavation du reste à -7.0 m



Excavation stages

T = 3.2. Excavation zone A jusqu’à -9.3 m (f.f.)



Excavation stages

T = 3.4. Excavation de la moitié du reste jusqu’à -9.3 m



Excavation stages

T = 3.6. Sous-radier à -9.3 m sur la moitié de la surface



Excavation stages

T = 5

T = 4. Excavation du reste à -9.3 m, puis fin du sous-radierT = 5. Application des charges de service du bâtiment



Results: final horizontal displacements

uz

A

B



Results: horizontal displacements evolution

-0.01

0

0.01

0.02

0.03

0.04

0.05

0 1 2 3 4 5

Etape

Dép

lace

men

t [m

]

Point A Point B



Results: final horizontal displacements



Results: final vertical displacements



Results: forces in the bracing



Results: moments in the slurry wall



Results: moments in the slurry wall



Water : particular study

15 m

17.2 m



Water : simplified 3D model

9.3 m

8.0 m

3.5 mRemblai K = 10-5 m/s épaisseur = 3.5 à 7.5 m

Glacio-sableux K = 10-5 m/s épaisseur = 4 m

Glacio-argileux mou K = 10-10 m/s épaisseur = 7.6 m

Fluvio-glaciaire K = 10-3 m/s épaisseur = 3.7 m

Glacio-argileux K = 10-8 m/s épaisseur = 4 m

Moraine K = 10-9 m/s épaisseur = 6 m

412.7 msm = 0.0

Molasse imperméable Well (model with/without) K = 10-3 m/s e= 15 m



Water : simplified 3D model with well

A = 15 * 17.2 = 258 m2

0.0-25

.0-50

.0

-100.0 -75.0 -50.0 -25.0 0.0

FLUID VELOCITIESt = 4.0 [day] Z_SOIL.PC 2003 v.6.26 Expert License No: -------- Company : ZACE Author : ZACE Date : 2007-02-15 09:46:01 File : C:\Mandats\GeoMod\M686_Orange\Technique\14fev\2D\orange_coupeCFF_2x2_paroiBeam_puits_Eunl_OKTitle : Zsoil example

3.207e+00

EXTR-VX5.131e+00-9.283e-01

EXTR-VY4.483e+00-2.413e+00

MAX-VEL.5.157e+00

UNIT[m/day]

Coupe 2D avec tranchées drainantesTranche 3D avec puits, esp. = 15 m



Water : simplified 3D model

eClay – low permeability

Model Thickness of the « impermeable »

layer

Well Flow in the excavated area

( 258 m2)

Flow for the entire

excavation (3200 m2)

Simple 1 5.30 m Yes 65.7 m3/d 815 m3/d

Simple 2 5.30 m No 2.4e-3 m3/d 30 litres/d

Simple 3 1.35 m No 9.7e-3 m3/d 120 litres/d



Water : 3D model

Low permeability

High permeability



Water : 3D model



Water : 3D model

1625 m3 / jour



Water : 3D model

0.04 m3 / jourImpermeable wall



Impermeable wall



Temperature effect on bracing : 2D modelgeneral considerations for T = 30 °

Free truss: l = T L/2 = 5 mm

Fixed conditions F = 1000 kN

Imposed displacement F = 165 kN

0.0

-7.5

-15

.0

-7.5 0.0 7.5 15.0

DEFORMED MESHt-ref.= 4.0 [day] t = 5.0 [day] Z_SOIL.PC 2003 v.6.26 Expert License No: -------- Company : ZACE Author : ZACE Date : 2007-03-08 08:29:12 File : C:\Mandats\GeoMod\M686_Orange\Technique\14fev\2D\orange_coupeCFF_2x2_paroiBeam_puits_Eunl_OK_deltaU5mmTitle : Zsoil example

2.771e-03

EXTR-U4.022e-04-5.849e-03

EXTR-V9.101e-04-9.855e-04

MAX-DISP5.896e-03

UNIT[m]

ux imposé = - 5 mmux = - 4.2 mm



Temperature effect on bracing : 2D modelimposing T on bracing (Q4)

0.0

-5.0

-10

.0

-5.0 0.0 5.0 10.0 15.0

TEMPERATUREt = 2.0 [day] Z_SOIL.PC 2003 v.6.26 Expert License No: -------- Company : ZACE Author : ZACE Date : 2007-03-08 09:14:18 File : C:\Mandats\GeoMod\M686_Orange\Technique\Simple_heat\orange_coupeCFF_heat2Title : Zsoil example

0 1.000e+01

1 1.150e+01

2 1.300e+01

3 1.450e+01

4 1.600e+01

5 1.750e+01

6 1.900e+01

7 2.050e+01

8 2.200e+01

9 2.350e+01

10 2.500e+01

11 2.650e+01

12 2.800e+01

13 2.950e+01

14 3.100e+01

15 3.250e+01

16 3.400e+01

17 3.550e+01

18 3.700e+01

19 3.850e+01

20 4.000e+01

UNIT[C]

T : from 10 °C to 40 °C => T = 30 °C

T = 10 °C = cte



Temperature effect on bracing : 2D modelimposing T on bracing

0.0

-7.5

-15

.0

-15.0 -7.5 0.0 7.5 15.0

DEFORMED MESHt-ref.= 1.0 [day] t = 2.0 [day] Z_SOIL.PC 2003 v.6.26 Expert License No: -------- Company : ZACE Author : ZACE Date : 2007-03-08 10:39:04 File : C:\Mandats\GeoMod\M686_Orange\Technique\Simple_heat\orange_coupeCFF_heat+mech2Title : Zsoil example

1.885e-03

EXTR-U4.055e-04-6.979e-03

EXTR-V7.084e-03-1.010e-03

MAX-DISP7.084e-03

UNIT[m]

ux = 0 (imposed)

N=230 kN



Conclusions

Currently under construction

•Predictions in the range of deformations and forces

•Horizontal displacements slightly > measurements•Linked mainly to:

- « conservative » evaluation of and c- real water behaviour

Commend, Mellal, Geiser – 08.2007 Z_Soil Day 2007 Lausanne, 27th August 2007 Numerical Simulation of Earthworks and Retaining System for an Excavation.

Documents

soil day

d model slide

jour slide

bracing slide

b slide

btiment slide

dcharge slide

surface slide