山地灾害与地表过程重点实验室知识库

对加入1%纳米硅的黏性砂土进行温度-2 ℃、围压0.3 ~ 18 MPa的常规三轴压缩试验。试验结果表明:掺入纳米硅的冻结黏性砂土强度明显提高,在sigma_3 = 3 MPa时强度提高甚至达到130%。将强度随围压的变化分成三个阶段:强化阶段,压融阶段,残余阶段。试验应力-应变曲线具有应变软化特性,修正的Duncan-Chang双曲线模型与其吻合良好。通过对修正的Duncan-Chang双曲线模型进行微分,分析得到初始切线模量随围压的变化可分成强化、压融和残余三个阶段。

A series of triaxial compressive tests on frozen clay sand with 1% nano-silicon were carried out under confining pressure of 0.3 ~ 18 MPa at -2 ℃. The test results show that the strength of frozen soil with nanosilicon has a significant growth,and the proportion of growth even reaches 130% under 3 MPa. The strength changes with increasing confining pressure in three distinct phases: strengthen phase,pressure melting phase and residual phase. The stress-strain curves show strain-softening under various confining pressures. The improved Duncan-Chang hyperbolic model is taken to simulate the stress-strain behaviors and can well describe the strainsoftening. Through differentiating the improved Duncan-Chang hyperbolic model,a relation between initial tangent modulus and confining pressure is obtained,which can be divided into three phases: strengthen phase, pressure melting phase and residual phase.