应力路径对重塑黏土有效抗剪强度参数的影响

为探讨应力路径对黏土有效抗剪强度参数的影响,即临界状态线的惟一性问题,在确保试样的初始状态、应力历史、排水条件、加荷速率、试验仪器、破坏取值标准均一致的前提下,进行了常规三轴压缩与等p三轴压缩应力路径下同种重塑黏土的固结排水剪切试验.得到了两种应力路径下的有效抗剪强度参数和临界状态线参数,试验结果证实不同应力路径下重塑黏土有效抗剪强度参数有较大差别,临界状态线不惟一.定性分析表明:相对于常规三轴压缩路径,重塑黏土在等p三轴压缩路径下具有较低、有效内摩擦角的原因是剪切过程中围压的降低造成侧向卸荷引起的土体抗剪能力下降;产生凝聚力的原因是在排水剪切过程中存在超固结效应.

Influence of stress path on effective shear strength parameters of reshaped clay

In order to study the Influence of stress path on effective shear strength parameters and the uniqueness of critical state line for clay,on the premise of ensuring the identity of initial condition,stress history,drainage condition,shear strain rate,tester,failure standard for soil samples,the drained triaxial compression tests under the stress paths of conventional triaxial compression and the mean normal stress remains constant were carried out for normally consolidated reshaped clay,the parameters of effective shear strength and critical state line under the two stress paths were obtained,these results demonstrated that the influence of stress path on effective shear strength parameters were considerably large and could not be neglected,and the critical state line was not unique.Qualitative analysis showed that the reason of a lower effective angle of internal friction of reshaped clay under the stress path of the mean normal stress remains constant was the falling of shear capacity produced by the falling of confining pressure,the cause of generation of cohesion was the over-consolidation effect,compared with that under the stress path of conventional triaxial compression.