不同含水量黄土-筋带接触特性试验及应用研究

Test of Mechanical Behavior of Loess-Geobelt Interface with Different Water Content

黄土属于水敏感性地质材料,不同含水量条件下黄土-加筋带接触面强度明显不同.为了获得此接触面剪切强度随含水量的变化规律,进行了系列不同含水量条件下黄土-加筋带接触面的直接剪切试验研究.试验结果表明,不同含水量的接触面剪切强度均满足莫尔-库仑准则,内摩擦角和黏聚力随含水量的增大而非线性减小.利用该试验结果对某黄土基坑加筋墙设计方案进行了不同含水量条件的校核,结果表明原方案没有考虑含水量增大对加筋墙内部稳定性的削弱作用,存在安全隐患,最后对原方案进行了修改使之满足含水量适当增大条件下的加筋墙内部稳定要求.

Loess is a special deposit which is very sensitive to water.Shear strength of loess-geobelt＇s interface changes with water content significantly.A series of direct shear tests for this interface with different water content are performed to obtain the relationship between water content and shear strength.The test results show that interface＇s shear strength of different water content meets Mohr-Coulomb criterion,and interface＇s friction angle and cohesion decreases nonlinearly with increasing water content.Then according to the test results,stability of the designed foundation ditch＇s reinforced earth wall in loess area is checked.The computing results indicate that the old design is unsafe because it has not taken the negative effect of increasing water contents into consideration.Finally,a new design is proposed which is able to satisfy the reinforced earth wall＇s inner stability with increasing water content properly.