复杂应力状态下土体有效动强度指标的确定

Determination of Effective Dynamic Strength Index of Soils under Complex Stress

基于俞茂宏统一强度理论 ,研究了砂土在复杂应力状态下的动强度及其指标确定的新方法 .考虑到动荷作用的特点 ,把动应变和极限平衡理论有机地联系起来 ,提出了考虑中间主应力的双剪动态极限平衡概念 ,探讨了它在砂土液化中的应用 ,并给出了确定有效动强度指标的方法 ,得出了基于双剪动态极限平衡法求得的有效动强度指标不是常数 ,而是随三向应力状态、不同的破坏标准而变化的结论 .这种方法不仅适用于砂土 ,而且也适用于粉土 .

A new method was proposed to determine the dynamic shear stress and dynamic strength index of soil under the complex stress, based on the Yu Maohong's unified strength theory. By connecting the dynamic strain with the theory of limit equilibrium, the concept of twin shear dynamic limit equilibrium was put forward to consider the effect of intermediate principal stress. And this concept can help us to find the possibility of liquefaction of soil during earthquake. A method to determine the effective strength indexes based on the above concept was given. It is shown that this index is a function of the 3-D stress states and the failure criteria. This method may be applied to both silty and sandy soils.