中文摘要：

冻土的变形和强度受温度、水分及压力的影响甚为显著。通过对-6℃的冻结粉质黏土在初始含水率为12.5%~20%范围内进行一系列的三轴试验,分析初始含水状态对冻土变形和强度的影响规律。研究发现,当初始含水率较低时,随着围压的增大,冻结粉质黏土相继出现应变软化和应变硬化特征;当初始含水率大于16%时,其应力-应变关系主要呈现出应变软化特征;随着初始含水率的增大,初始切线模量随围压从线性缓慢增大逐渐过渡为抛物线形的分布。同时,根据包络线定理,建立非线性摩尔-库仑强度准则,用以描述初始含水率为12.5%、14%和16%的冻结粉质黏土强度随围压变化的非线性;当初始含水率为18%和20%时,其强度可用线性摩尔-库仑强度准则描述。

英文摘要：

Temperature, water content and pressure strongly influence the deformation and strength behaviors of frozen soil. In order to study the effect of initial water state on deformation and strength behaviors of frozen silty clay, a series of triaxial compression tests has been conducted under initial water contents varying from 12.5% to 20% at-6 ℃. The results show that the frozen silty clay presents strain softening and strain hardening successively under low initial water content with increasing the confining pressure, but the frozen silty clay mainly exhibits strain softening when the initial water content is more than 16%. With increasing the initial water content, the relationship between initial tangent modulus and confining pressure changes from linear increase to parabola form. Meanwhile, in order to describe the nonlinearity between strength and confining pressure of frozen silty clay under the initial water contents of 12.5%, 14% and 16%, a nonlinear Mohr-Coulomb strength criterion is built based on the envelope theory. The linear Mohr-Coulomb strength criterion can describe the strength development with confining pressure of frozen silty clay under the initial water contents of 18% and 20%.