非饱和土力学理论的研究进展

回顾了非饱和土有效应力的发展，目前普遍认同采用两个应力变量来建立本构模型，且对基质吸力中毛细和粘吸两部分作用进行了阐述。分析了非饱和土强度问题,包括抗剪强度和抗拉强度。讨论了非饱和土的本构模型问题,包括基于净应力和基质吸力的弹塑性模型，基于Bishop有效应力和基质吸力的水力力学耦合弹塑性模型,以及双孔隙结构的模型。最后探讨了热力学方法和多孔介质理论在非饱和土中的应用,基于多孔介质理论在多场耦合条件下土体复杂的行为是当前值得研究的问题。

RESEARCH PROGRESS OF UNSATURATED SOIL MECHANICS

This paper firstly reviews the studies of the effective stress of unsaturated soils and points out that two stress variables are preferred to be chosen to establish a constitutive model at present. The paper also explains the definition of the matric suction, which involves the effects of the capillary component and the adsorptive component. Secondly the paper discusses the strength of unsaturated soils. The shear strength is usually formulated by the extended Mohr-Coulomb Criterion. The tensile strength also affects the soil behavior due to the capillary effect and thus cannot be ignored. Thirdly, the paper reviews the studies of the constitutive models for unsaturated soils, including the models based on the net stress and the matric suction and that based on the Bishop effective stress and the matric suction. The double pore structure model is also discussed. Finally, the paper addresses the applications of the thermodynamic method and the porous media theory in unsaturated soils. It is shown that these two methods-using the thermodynamic principles to establish the constitutive framework, and using the porous media theory to study the complicated coupling effect of unsaturated soils are subjects very worthy to be developed.