土体中间主应力确定及其对临界值影响

Determination of intermediate principal stress of soil mass and its influence on critical values under plane strain conditions

分析比较平面应变状态下中间主应力的各种形式,根据侧限压缩试验的特殊应力应变条件,推导了一个与土性参数有关的中间主应力表达式.该表达式可简单地通过三轴压缩试验所得的参数来确定,同时还可以简单反映土体应力历史对土体强度的影响.将该表达式与SMP准则和Lade准则结合,建立了平面应变状态下土性参数与三轴压缩状态土性参数的关系,通过试验数据的分析比较看出,所得的中间主应力能更好地反映土体的实际性状,对于SMP准则和Lade准则均有很好的适用性.

Through analysing and comparing kinds of the intermediate principal stress forms under plane strain conditions and based on the particular conditions of stress-strain in oedometric experiments, an expression of the intermediate principal stress that is related with parameters of soil properties is deduced and confirmed. The expression is simply confirmed by parameters gained by triaxial compression experiments, and it can also simplly reflect the influence of soil mass stress history on soil strength. By combining SMP criterion and Lade criterion with the expression of the intermediate principal stress, the relationship of parameters of soil properties is established between plane strain state and triaxial compression state. Analysis and comparison of the experiment data show that the intermediate principal stress proposed herein well reflects the practical behavior of the soils mass and is very suitable for SMP criterion and Lade criterion.