中文摘要：

采用空心圆柱扭剪仪对主应力轴方向固定不变定向不排水剪切应力路径下杭州原状软黏土破坏标准进行试验研究,重点探讨了中主应力参数b、大主应力方向角α及孔压积累对剪切过程中黏土抗剪强度的影响,并提出原状软黏土剪切破坏的标准。试验结果表明,中主应力参数的变化没有对应力应变变化模式和试验应力路径产生影响,随着中主应力参数的增大,黏土抗剪强度的变化并没有呈现出一定的规律性;大主应力方向角对原状软黏土强度的影响反映出原生各向异性对黏土抗剪强度的控制作用;黏土样在剪切后期会产生显著的孔压积累,影响了黏土强度的发挥。考虑中主应力参数等影响因素,通过分析广义剪应力-应变曲线的变化情况,取广义剪应力qJ的峰值作为原状软黏土的剪切破坏标准。

英文摘要：

A hollow cylinder apparatus was used to study failure criteria for Hangzhou intact soft clay under undrained shear stress path with fixed principal stress direction;then the impacts of coefficient of intermediate principal stress,angle of large principal stress direction and pore pressure accumulation on shear strength of clay were emphatically discussed;and shear failure criterion of intact soft clay was proposed.Test results revealed that the coefficient of intermediate principal stress did not affect the variable pattern between stress and strain and stress path;and with the increase of coefficient of intermediate principal stress,the change of shear strength of clay did not show some regularity.The impact of angle of large principal stress direction on the strength of intact soft clay reflected that inherent anisotropy controlled the shear strength of clay.Pore pressure remarkably accumulated in the late period of shearing,which impacted on the performance of the strength of clay.Considering the influencing factors such as coefficient of intermediate principal stress,we used the maximum of generalized shear stress as shear failure criterion of intact soft clay by analyzing changes of generalized shear stress-strain curves.