On the use of the Hardening Soil modelg
Rafal OBRZUDRafal OBRZUD
GeoMod Ing. SA, Lausanne
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Content
IntroductionIntroduction
Example 1 – Berlin Sand - excavation problem
Example 2 – Montreux – 3D excavation problemExample 2 Montreux 3D excavation problem
Example 3 – London Clay - tunnel excavation
Example 4 – Almere - trial embankment problem
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Why do we need advanced constitutive models?
GEOENGINEERING COMPUTINGS
LIMIT STATE ANALYSIS DEFORMATION ANALYSIS
Bearing capacity Pile, retaining wall deflection
Slope, wall stability Supported deep excavations
Tunnel excavationsTunnel excavations
Consolidation
Basic models e.g. Mohr-Coulomb Advanced soil models
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Basic differences between implemented soil models
Mohr-Coulomb
qi ld
K0-line
yieldsurface q
p’
Linearelasticdomain
K0-p’
q p’
K0unloading
E Eur
ε1
E=Eur
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Basic differences between implemented soil models
Volumetric cap Mohr-Coulomb
Volumetric cap models
qi ld
q isotropich d i
K0-line
yieldsurface
hardeningmechanism
q
p’ p’
σ1’ constant
Linearelasticdomain
Linearelasticdomain
p’ p’
q q Stiffnessdegradation
p’
E Eur EurE
ε1 ε1
E=Eur E < Eur
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Basic differences between implemented soil models
Volumetric cap Hardening Soil Mohr-Coulomb
Volumetric cap models
Hardening Soil models
qi ld
q qisotropich d i
K0-line
yieldsurface
hardeningmechanism + shear
hardeningmechanism
p’
Linearelasticdomain
p’ p’
Linearelasticdomain
p’ p’ p’
q q qStiffnessdegradation
Stiffnessdegradation
NON-LINEAR elastic domain
E EurEurEur
E0
E E
ε1 ε1 ε1
E=Eur E<EurEur E0
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Basic differences between implemented soil models
1 Mohr‐Coulomb
Small strain stiffness in geotechnical practice
0.8
1
nessG/G
0[‐]
o Cou o b
Modified Cam Clay
Cap model
HS‐Standard
HS‐Small
Non‐linear elasticityat very small strains
0.4
0.6
lized
soilstiffn
Linear elasticity at
Linearelasticityat smallstrains
0
0.2
1E‐06 1E‐05 0.0001 0.001 0.01 0.1
Norma
Axial Strain ε [‐]
Linear elasticity atvery small strains
1E 06 1E 05 0.0001 0.001 0.01 0.1Axial Strain ε 1 [‐]
e.g. Atkinson, Jardine and many others
Shear strain [‐]
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Content
IntroductionIntroduction
Example 1 – Berlin Sand - excavation problem
Example 2 – Montreux – 3D excavation problemExample 2 Montreux 3D excavation problem
Example 3 – London Clay - tunnel excavation
Example 4 – Almere - trial embankment problem
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Example 1: Berlin Sand - excavation problem (Schweiger, 2002)
Engineering draft FE mesh
Sand
Sand
Anchors
Diaphragm wall
Impermeablebarrier
Truty (2008)
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Truty (2008)
Example 1: Berlin Sand - excavation problem
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Content
IntroductionIntroduction
Example 1 – Berlin Sand - excavation problem
Example 2 – Montreux – 3D excavation problemExample 2 Montreux 3D excavation problem
Example 3 – London Clay - tunnel excavation
Example 4 – Almere - trial embankment problem
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Example 2: – Montreux – 3D excavation problem
No continuum elems: 41’108No continuum elems: 41 108
Existing building
Av. des Alpes
15 20m diaphragm15-20m diaphragmwall excavation
No shell elems: 3’412No truss elems: 930
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
No truss elems: 930
Example 2: – Montreux – 3D excavation problem
Section A‐A
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Example 2: – Montreux – 3D excavation problem
Mohr-Coulomb HS-SmallStrain
Lifting of retaining wall Settlements behind the retaining wall
UY 1 5
E = 60MPa
UY = ‐0.5cmUY = +1.5cm
Eur = 132MPa
E0 = 264MPa
UY = +5.3cm
E50 = 44MPa
at 15mE = 360MPa
Section A‐A Section A‐A
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Content
IntroductionIntroduction
Example 1 – Berlin Sand - excavation problem
Example 2 – Montreux – 3D excavation problemExample 2 Montreux 3D excavation problem
Example 3 – London Clay - tunnel excavation
Example 4 – Almere - trial embankment problem
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Example 3: – London Clay - tunnel excavation (Addenbrooke et al., 1997)
Problem statement FE meshProblem statement FE mesh
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Example 3: – London Clay - tunnel excavation (Addenbrooke et al., 1997)
50
800
1000
1200
[‐]
CIUE test
CAUE test
CIUE HS‐Small
CIUE MC 30
35
40
45 CIUE test
HS‐Small ‐ q
J4 ‐ q
MC ‐ q
200
400
600
E sud/ p' [
10
15
20
25
q [kPa]
0
1E‐05 0.0001 0.001 0.01 0.1 1
Axial strain [%]
0
5
10
‐2.08E‐17 0.002 0.004 0.006 0.008 0.01600Axial strain [%]
400
500
CIUE test
HS‐Small ‐ q
J4 ‐ q
MC ‐ q
100
200
300q [kPa]
0
100
0 0.1 0.2 0.3 0.4
A i l t i [%]Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Axial strain [%]
Example 3: – London Clay - tunnel excavation
Mohr-CoulombTunnel level:E = 183 MPa
max uabs= 16.8 mm
HS-SmallStrainTunnel level:E0 = 500 MPaEur = 90 MpaE 40 MPE50 = 40 MPa
max uabs= 61.3 mm
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Example 3: – London Clay - tunnel excavation
i f b d l0
]Excavation of Westbound Tunnel
‐10
‐5
nts [m
m]
‐15
ettlem
en
Field data
‐20
urface se Field data
M‐C (Ko=1.0, E=6000z kPa)
HS‐Std (Ko=1.0)
‐30
‐25Su HS‐Small (Ko=1.0)
Model ‐ J4 (Ko=1.5)1st tunnel30
‐10 0 10 20 30 40 50 60
Offset from the westbound tunnel [m]
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Content
IntroductionIntroduction
Example 1 – Berlin Sand - excavation problem
Example 2 – Montreux – 3D excavation problemExample 2 Montreux 3D excavation problem
Example 3 – London Clay - tunnel excavation
Example 4 – Almere - trial embankment problem
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Example 4: – Almere - trial embankment problem (Bringreve & Vermeer (1992)Rowe, Soderma (1985) )
Sand fill Retaining bank
2m
Sand layer
Organic Clay OCR =2
Stages:1. Excavation2. Embankment + Fillba e3. Consolidation
Clay layer modeled with: Mohr-Coulomb and Hardening Soil-SmallStrain
EMC = 13 750 kPa Eur = 2 EMC
E50 = EMC /2
E0 = 2 Eur
E E
σref = 30kPa
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Eoed = E50
Example 4: – Almere - trial embankment problem
Pt - A
Pt - B
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
Example 4: – Almere - trial embankment problem
Pt APt A Pt B
Pt B ‐ Embankment basePt A ‐ Embankment top
2
‐1
0
mm]
‐10
‐5
0
mm]
‐4
‐3
‐2
acem
ent [m
‐20
‐15
10
cemen
t [m
‐6
‐5
‐4
Y‐displa
Mohr ‐ Coulomb35
‐30
‐25
Y‐displa
‐7
0 5 10 15 20 25X‐displacements [mm]
HS‐SmallStrain‐40
‐35
‐4 ‐2 0 2 4 6 8X‐displacements [mm]
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model
X displacements [mm]X displacements [mm]
Summary
Hardening Soil-SmallStrain model:Hardening Soil-SmallStrain model:
correctly reproduces strong reduction of soil stiffness with correctly reproduces strong reduction of soil stiffness with increasing shear strain amplitudes
is recommended for Serviceability Limit State analyses as it generally closer predicts soil behavior and field measurements than generally closer predicts soil behavior and field measurements than basic linear-elasticity models
is applicable to most soils as it accounts for pre-failure nonlinearities for both sand and clay type materials regardless of nonlinearities for both sand and clay type materials regardless of overconsolidation state
Rafal Obrzud25 years of Z_Soil30.08.2010, Lausanne
On the use of the Hardening Soil model