正城滑坡滑带土抗剪强度参数试验研究

Experimental Research on Shear Strength Parameters of Slip Zone Soils in Zhengcheng Landslide

在降雨或融雪条件下,滑带土含水量增加导致抗剪强度降低,下滑力大于抗滑力从而引发黄土滑坡,因此研究滑带土的抗剪强度特性对分析判断黄土滑坡的形成和发生具有重要意义。在正城滑坡滑带土不同含水率下固结不排水三轴试验的基础上,与反算法得到的抗剪强度参数相比,结果表明滑带土的内聚力(c)和内摩擦角(φ)都会随着含水率的增加而降低,并且在塑限附近抗剪强度降低较快,反算法得到的滑坡启动强度参数和含水率与塑限对应的参数几乎相同,同时也证明了黄土滑坡的启动含水率为塑限。

Under the conditions of rainfall or snow melting, the increase of water content of slip zone soils will lead to the decrease of shear strength, so that the slide force is greater than the anti-slip force, which consequently results in the occurrence of loess landslide. Therefore, it is of great significance to study the shear strength of slip zone soils, which can provide guidance for analyzing the formation and occurrence of loess landslide, A series of consolidated-undrained triaxial tests were conducted on slip zone soils of Zhengcheng landslide under different water contents, and the obtained shear strength parameters were compared with that calculated by back-calculation method. It was concluded that the cohesion （c） and internal friction angle （φ） would both decrease with the increase of water content, and the shear strength decreased rapidly near the plastic limit. In addition, the mobilized strength parameters and the water content obtained by back-calculation method were almost the same as the parameters corresponding to the plastic limit, so it was also proved that the plastic limit was starting water content for loess landslide.