不同含水量条件下红砂岩泥化夹层的剪切特性

摘要

为了探讨不同含水量条件下泥化夹层的剪切特性，通过等应变直剪仪对红砂岩泥化夹层进行不同含水率和法向应力的直剪试验，研究了红砂岩泥化夹层的剪切力学行为．结果表明：剪应力—剪切位移曲线为滑移型曲线，正应力越小，达到剪切强度所需的剪切位移也越小；随着含水量的增加，泥化夹层的剪切强度明显降低，剪切强度参数中内摩擦角非线性减小，而粘结力先增大后减小；存在一个临界含水量值，当含水量小于该值时，粘结力随含水量的增大而增大，当含水量超过该值时，粘结力随含水量的增大而减小．%In order to study the shear characteristics of siltized intercalation in red sandstone at different water contents, the constant strain direct shear apparatus was used to carry out the direct shear tests for siltized intercalation in red sandstone at different water contents and normal stresses, and the shear mechanical behavior of siltized intercalation in red sandstone was investigated. The results show that the shear stress-shear displacement curves belong to the sliding type. The smaller the normal stress is, the smaller the shear displacement to reach the shear strength is. With increasing the water content, the shear strength of siltized intercalation decreases obviously and the internal friction angle in the shear strength parameters decreases nonlinearly, while the cohesive force increases firstly and then decreases. There exists a critical water content （LWC） value. When the water content is smaller than the value, the cohesive force will increase with increasing the water content. When the water content is larger than the value, the cohesive force will decrease with increasing the water content.