An elasto-plastic model for unsaturated soil incorporating the effects of suction and degree of saturation on mechanical behaviour

被引:539
作者
Gallipoli, D [1 ]
Gens, A
Sharma, R
Vaunat, J
机构
[1] Univ Politecn Cataluna, Dept Ingn Terreno, Barcelona, Spain
[2] Univ Bradford, Bradford BD7 1DP, W Yorkshire, England
[3] Univ Oxford, Oxford OX1 2JD, England
来源
GEOTECHNIQUE | 2003年 / 53卷 / 01期
关键词
clays; constitutive relations; partial saturation; plasticity; suction;
D O I
10.1680/geot.53.1.123.37251
中图分类号
P5 [地质学];
学科分类号
0709 ; 081803 ;
摘要
The paper presents an elasto-plastic model for unsaturated soils that takes explicitly into account the mechanisms with which suction affects mechanical behaviour as well as their dependence on degree of saturation. The proposed model is formulated in terms of two constitutive variables directly related to these suction mechanisms: the average skeleton stress, which includes the average fluid pressure acting on the soil pores, and an additional scalar constitutive variable, xi, related to the magnitude of the bonding effect exerted by meniscus water at the inter-particle contacts. The formulation of the model in terms of variables closely related to specific behaviour mechanisms leads to a remarkable unification of experimental results of tests carried out with different suctions. The analysis of experimental isotropic compression data strongly suggests that the quotient between the void ratio, e, of an unsaturated soil and the void ratio e(s), corresponding to the saturated state at the same average soil skeleton stress, is a unique function of the bonding effect due to water menisci at the inter-particle contacts. The same result is obtained when examining critical states at different suctions. Based on these observations, an elasto-plastic constitutive model is developed using a single yield surface the size of which is controlled by volumetric hardening. In spite of this simplicity, it is shown that the model reproduces correctly many important features of unsaturated soil behaviour. It is especially remarkable that, although only one yield surface is used in the formulation of the model, the irreversible behaviour in wetting-drying cycles is well captured. Because of the behaviour normalisation achieved by the model, the resulting constitutive law is economical in terms of the number of tests required for parameter determination.
引用
收藏
页码:123 / 135
页数:13
相关论文
共 25 条
[1]  
Alonso EE, 1995, UNSATURATED SOILS, VOLS 1 AND 2, P11
[2]   A CONSTITUTIVE MODEL FOR PARTIALLY SATURATED SOILS [J].
ALONSO, EE ;
GENS, A ;
JOSA, A .
GEOTECHNIQUE, 1990, 40 (03) :405-430
[3]  
Bishop A.W., 1959, TEKNISK UKEBLAD, V39, P859, DOI DOI 10.1021/AC60166A763
[4]   Elastoplastic soil constitutive laws generalized to partially saturated states [J].
Bolzon, G ;
Schrefler, BA ;
Zienkiewicz, OC .
GEOTECHNIQUE, 1996, 46 (02) :279-289
[5]   Yielding and plastic behaviour of an unsaturated compacted silt [J].
Cui, YJ ;
Delage, P .
GEOTECHNIQUE, 1996, 46 (02) :291-311
[7]   Modelling the variation of degree of saturation in a deformable unsaturated soil [J].
Gallipoli, D ;
Wheeler, SJ ;
Karstunen, M .
GEOTECHNIQUE, 2003, 53 (01) :105-112
[8]   A FRAMEWORK FOR THE BEHAVIOR OF UNSATURATED EXPANSIVE CLAYS [J].
GENS, A ;
ALONSO, EE .
CANADIAN GEOTECHNICAL JOURNAL, 1992, 29 (06) :1013-1032
[9]  
Gens A., 1995, CONSTITUTIVE LAWS BT, P129