黄土大剪切位移下的强度特性研究

摘要

By using 4-linking ZJ type strain-control direct shear apparatus,a repeated shear test of Yan′an typical loess landslides in-door loess was carried out.It explores the shear displacement and strength characteristics of loess under natural and saturated conditions under different pressures,determines the peak and residual strength.The test results show that under the condition of natural moisture content,the peak strength and residual value increased,the cohesion is significantly reduced with the water content increased,internal friction angle is relatively stable and only a little change occurred;On the same soil,the residual strength is significantly less than the peak intensity values;As result of self-property of the soil,residual strength is a stable value and it is not related to historical influence of the force of soil.%本文采用ZJ型4联应变控制直剪仪，对延安典型黄土滑坡带的土样进行不同压力下反复剪切试验，分析了天然和饱和状态下的黄土在不同压力下的剪切位移和强度特性，以确定其峰值和残余强度。试验结果表明：天然含水量条件下，峰值和残余值强度均较高，随着含水量的增加，土体的粘聚力显著减小，内摩擦角基本上变化不大；对同一种土体来说，残余强度值明显小于峰值强度值；残余强度是一个稳定值，是土体本身的性质，与土体的受力历史无关。