非饱和土等效固结变形特性与一维固结变形分析方法

Equivalent consolidation deformation properties and one-dimensional analysis method of unsaturated soils

非饱和土的固结变形特性及分析方法一直是土力学的研究热点。由于非饱和土是一种三相的多孔松散介质,三相之间不仅具有力学效应复杂多变的收缩膜,而且还存在气、固与固、液之间的电化学作用和物理作用以及它们物理性态变化的影响,因此,仅依据吸力特征量来反映固、液、气及收缩膜之间的联系对于认识非饱和土力学特性存在很大困难。从非饱和土客观存在的固结变形变化以及固结变形稳定时固、液、气共同构成的等效骨架承担压缩应力出发,提出将复杂多变的非饱和土固、液、气三相及收缩膜和各相的物理化学表观作用等效为骨架相和流体相,通过压缩、固结试验揭示了非饱和土固结过程的等效骨架相应力和等效流体相压力的变化规律、瞬时压缩变形特性,以及等效固结系数,将复杂的非饱和土固结问题简化为两相耦合作用问题,建立了一种实用的非饱和土一维等效固结分析方法。

The consolidation deformation characteristics and analysis methods of unsaturated soil are the key issues in the field of soil mechanics. The unsaturated soil is a kind of three-phase porous medium. There is not only the interaction among the solid phase, liquid phase and gaseous phase, the mechanical effect from complicated shrinkable film but also the morphological and chemical change in soluble mineral property. Therefore, it is not enough to only establish an association among the solid phase, liquid phase, gaseous phase and shrinkable film by suction characteristic quantity in the study on mechanical behaviors of the unsaturated soil. The solid phase, liquid phase, gaseous phase, shrinkable film and mineral components behavior apparent effect are considered as the equivalent fabric phase and fluid phase. The equivalent fabric phase has both the stress resistance and the shear performance. The equivalent fluid phase only has the stress resistance. It can reduce those relative to the skeleton phase. Complex multiphase of the unsaturated soil is the equivalent fabric phase and fluid phase. So the complex consolidation of unsaturated soil can be solved by two-phase analysis method, which considers the transient compression deformation, the initial equivalent fabric stress and the movement of equivalent fluid phase. This paper sets up one-dimensional equivalent consolidation analysis method.