原位钻孔剪切试验在加筋土挡墙填土中的应用研究

Application study on in-situ borehole shear tests in reinforced soil retaining walls

为了给加筋土挡墙进行形变和稳定性分析的数值模拟提供一定参考数据,利用原位钻孔剪切试验测定挡土墙填土的抗剪强度参数。通过使用剪切探头对孔壁施加不同的法向力的同时向上提拉剪切头,记录相应的剪切力峰值,并采用最小二乘法绘制摩尔—库伦包线。通过3组有效数据测得加筋土挡墙填土在含水率17.67%的情况下抗剪强度平均值为c=19.8kPa、φ=34.0°,与现场实际情况相符合。但试验过程中也发现原位钻孔剪切试验对孔壁质量较为敏感的问题。

In order to provide certain reference data for the numerical simulation of deformation and stability analysis of reinforced soil retaining wall,in-situ borehole shear tests are used to determine the shear strength parameters of retaining wall fill.By using the shear probe to apply different normal forces to the borehole wall while lifting the shear head upward,the corresponding peak shear force is recorded and the Mohr-Coulomb envelope is plotted by the least-squares method.The shear strength average values of the reinforced retaining wall fill in the case of 17.67%water content are measured as the c=19.8kPa,φ=34.0°by using three sets of valid data,which is in line with the actual situation in the field.However,the test process also finds that the in-situ borehole shear test is more sensitive to the quality of the borehole wall.