粒间吸引力对非饱和土变形及强度的影响分析

Function of Attraction between Particles Induced by Unsaturation on Deformation and Shear Strength in Unsaturated Soils

基于球形颗粒理想化最松散堆积模型,研究了弹性条件下外加静水压力和粒间吸引力对非饱和土变形和强度的不同影响.研究表明,对于变形问题,外加静水压力引起的变形包括颗粒缺位体积和弹性变形2部分;粒间吸引力引起的变形只包括颗粒的弹性变形.因此,在粒间吸引力作用下土体的体变要大大小于等值外加静水压力作用下产生的体变.对于强度问题,主要研究了摩擦力和咬合力.对于前者,2种加荷方式都有作用,但外加静水压力的作用要大于粒间吸引力的作用;对于后者,外加静水压力有增强作用而粒间吸引力则没有.

Based on elastic theory and an ideal four ball-shape particle packingmodel, functions of hydrostatic pressure posed on soil sample boundary and attraction between soil particles induced by unsaturation on volumetric deformation and shear strength are studied for unsaturated soils. The study shows that deformation induced by the former force system is composed of elastic deformation of all soil particles and volume of absent particles whereas deformation induced by the latter force system only consists of the first part. Therefore, the first kind of deformation is affirmatively larger than the second one when the two force systems have same magnitude. The shear strength of unsaturated soils can be divided into several parts including that induced by friction, part A and gnathodynamic, part B. The study shows that the part A that comes from hydrostatic pressure on boundary is larger than that comes from attraction between particles and the part B only exists in the first kind of situation.