非饱和土的塑性体应变与剪应变的相互作用原理

The Principle of Interaction Between Plastic Volumetric and Shear Strains for Unsaturated Soils

将岩土塑性体应变与剪应变的相互作用原理拓展到了非饱和土领域。除了塑性体应变与剪应变的相互作用外,在非饱和土中出现了两类新的相互作用,吸力-塑性体应变和孔隙气压力-塑性体应变。吸力具有二重性质,其对塑性体应变作用包括两个相反的方面。基于吸力性质,阐明了非饱和土的一些独特的性质,诸如有效应力参数的物理涵义,吸力对体积变化和前期固结压力的影响和湿陷机理等。另外,应用拓展的塑性体应变与剪应变相互作用原理,从理论上证明了非饱和土的临界状态线是存在的和唯一的,以及它与应力历史无关。

In this paper, the principle of interaction between plastic volumetric and shear strains for rock and soil has been extended to the field of unsaturated soils. Two new interactions of suction - plastic volumetric strain and pore air pressure - plastic volumetric strain appear in the unsaturated state of a soil besides the interaction between plastic volumetric and shear strains. The suction possesses a dual property. Thereby the effect of the suction on plastic volumetric strain includes two opposite aspects. By means of this property of suction, the physical significance of effective stress parameter, effects of suction on volume change and preconsolidation pressure, and the mechanism of collapse upon wetting all can be explained. In addition, it is theoretically proved by application of this principle of interaction that the critical state line for unsaturated soils exists, and is unique and independent of the stress history.