In this work an elastoplastic constitutive theory for unsaturated soils is presented. The proposed material model is formulated in the general framework of the theory of porous media and of the flow theory of plasticity. The model is based on an extension of the well-known MRS Lade model whereby the suction and the effective stress tensor are introduced as additional independent and dependent stress components, respectively. Consequently the cap and cone yield conditions of the MRS Lade model both in hardening and softening as well as the internal evolution laws in these regimes are redefined to include the dependency on the suction. The paper illustrates the predictive capability of the extended MRS Lade model for partially saturated soils. Finally, the condition for discontinuous bifurcation in elastoplastic partially saturated porous media as well as the localized failure predictions of the proposed material formulation for different suctions and stress states are also analyzed and discussed.

1.
Alonso
,
E.
,
Gens
,
A.
, and
Jose
,
A.
, 1990, “
A Constitutive Model for Partially Saturated Soils
,”
Geotechnique
0016-8505,
40
, pp.
405
430
.
2.
Schrefler
,
B.
, and
Zhan
,
X.
, 1993, “
A Fully Coupled Model for Water Flow and Airflow in Deformable Porous Media
,”
Water Resour. Res.
0043-1397,
29
, pp.
155
167
.
3.
Cui
,
Y.
,
Delage
,
P.
, and
Sultan
,
N.
, 1995, “
An Elastoplastic Model for Compacted Soils
,”
Proceedings of the First International Conference on Unsaturated Soil
,
E.
Alonso
and
P.
Delage
, eds.,
Balkema
,
Rotterdam
, Vol.
2
, pp.
703
709
.
4.
Bolzon
,
G.
,
Schrefler
,
B.
, and
Zienkiewicz
,
O.
, 1996, “
Elastoplastic Soil Constitutive Laws Generalised to Partially Saturated States
,”
Geotechnique
0016-8505,
46
, pp.
279
289
.
5.
Wheeler
,
S.
, and
Sivakumar
,
V.
, 1995, “
An Elastoplastic Critical State Framework for Unsaturated Soil
,”
Geotechnique
0016-8505,
45
, pp.
35
53
.
6.
Kohgo
,
Y.
,
Nakano
,
Y.
, and
Miyazaki
,
T.
, 1993, “
Theoretical Aspects of Constitutive Modelling for Unsaturated Soils
,”
Soils Found.
0038-0806,
33
, pp.
49
63
.
7.
Gens
,
A.
, 1995, “
Constitutive Modelling: Application to Compacted Soils
,”
Proceedings of the First International Conference on Unsaturated Soil
,
E.
Alonso
and
P.
Delage
, eds.,
Balkema
,
Rotterdam
, Vol.
3
, pp.
1179
1200
.
8.
Khalili
,
N.
, 2000, “
Application of the Effective Stress Principle to Volume Change in Unsaturated Soils
,”
Unsaturated Soils for Asia
,
H.
Rahardjo
et al.
, eds.,
Balkema
,
Rotterdam
, pp.
101
105
.
9.
Loret
,
B.
, and
Khalili
,
N.
, 2000, “
A Three-Phase Model for Unsaturated Soils
,”
Int. J. Numer. Analyt. Meth. Geomech.
0363-9061,
24
, pp.
893
927
.
10.
Sture
,
S.
,
Runesson
,
K.
, and
Macari-Pascualino
, 1989, “
Analysis and Calibration of a Three Invariant Plasticity Model for Granular Materials
,”
Ing.-Arch.
0020-1154,
59
, pp.
253
266
.
11.
Sheng
,
D.
,
Sloan
,
S. W.
,
Gens
,
A.
, and
Smith
,
D. W.
, 2003, “
Finite Element Formulation and Algorithms for Unsaturated Soils. Theory
,”
Int. J. Numer. Analyt. Meth. Geomech.
0363-9061,
27
, pp.
745
765
.
12.
Weihe
,
S.
, 1990, “
Implicit Integration Schemes for Multi-Surface Yield Criteria Subjected to Hardening/Softening Behavior
,” M.Sc. thesis, University of Colorado at Boulder.
13.
Schiava
,
R.
, 2002, “Modelacion Elastoplastica de Suelos Cohesivo-Friccionales Parcialmente Saturados,” M.Sc. thesis, Universidad Nacional de Santiago del Estero, Argentina.
14.
Willam
,
K.
, and
Warnke
,
E.
, 1975, “
Constitutive Models for the Triaxial Behaviour of Concrete
,”
Int. Assoc. Bridge Struct. Engrg. Proc.
,
19
, pp.
1
30
.
15.
Schrefler
,
B.
, and
Bolzon
,
G.
, 1997, “
Compaction in Gas Reservoirs Due to Capillary Effects
,”
Computational Plasticity
,
CIMNE
,
Barcelona
.
16.
Thomas
,
T.
, 1961,
Plastic Flow and Fracture in Solids
,
Academic
,
New York
.
17.
Hill
,
R.
, 1962, “
Acceleration Waves in Solids
,”
J. Mech. Phys. Solids
0022-5096,
10
, pp.
1
16
.
18.
Maxwell
,
J. C.
, 1873,
A Treatise in Elasticity and Magnetism
, Oxford.
19.
Peric
,
D.
, 1990, “
Localized Deformation and Failure Analysis of Pressure Sensitive Granular Materials
,” Ph.D. thesis, University of Colorado at Boulder.
This content is only available via PDF.
You do not currently have access to this content.