饱和砂土的动强度及破坏准则

Dynamic Strength and Failure Criterion of Saturated Sand

本文以饱和砂土的振动三轴试验和振动扭剪试验研究为基础,给出了动荷载下土的瞬态有效抗剪强度理论,阐明了土的瞬态有效抗剪强度,包括粘聚力c_t(对于饱和砂土,c_t=0)、内摩阻力σft′tgφd′和动粘滞力ηY_t三部分,建立了瞬态有效抗剪强度的一般表达式。试验表明,饱和砂土的动有效内摩擦角φd′和动粘滞系数η是稳定的土性直,有效摩擦应力空间中亦存在一个稳定的强度破坏面,且与松岗元准则相当一致,从而给出了动荷载下饱和砂土的破坏准则。

Based on the study of cyclic triaxial and torsioaal shear tests of saturated sand, the transient effective shear strength theory of soil' under cyclic loading is presented, which indicates that the transient effective shear strength of soil includes cohesion ct (saturated sand ct = 0), internal frictlonal resistance and dynamic viscous resistance and a general transient effective shear strength formula is founded. It is also verified by test results that the dynamic effective internal frictlonal angle and the dynamic viscosity coefficientη are stable soil behavior coefficients, and there is a stable strength failure plane in the effective frictional stress space which is comparable with Mastuoka's Criterion, and thence the failure criterion of saturated sand under cyclic loading is given.