压实黏土变角剪切试验及其尺寸效应

Study on Variable Angle Shear Test of Compacted Clay and Its Size Effect

滑带土的抗剪强度指标对于边坡稳定性分析具有重要作用,相比于直剪试验,变角剪切试验能更好的模拟滑带土的受力状态。利用岩土体变角剪切试验仪,对不同尺寸试样进行变角剪切试验,介绍了变角剪切试验研究压实黏土剪切参数的方法,结合Weibull统计尺寸效应理论研究压实黏土尺寸效应。结果表明:变角剪切试验结果符合幂函数型Mohr准则;与直剪试验测得的剪切参数相比,变角剪切试验得出的内摩擦角与直剪试验相近,黏聚力较直剪试验大;压实黏土的尺寸效应基本符合Weibull尺寸效应理论,经过修正的Weibull尺寸效应式能更好地描述压实黏土剪切强度的尺寸效应。

The shear strength parameters of soil in shear band play an important role in slope stability analysis. Compared with the direct shear test,variable angle shear test can simulate the stress state of slip band soil better. In this paper,variable angle shear tests are carried out on specimens of different sizes by means of rock and soil fracture tester. The method of studying shear parameters of compacted clay by variable angle shear tests is introduced. The size effect is studied with Weibull statistical size effect theory. The research shows that the results of variable angle shear test conform to the power function Mohr criterion;compared with the shear parameters measured by direct shear test,the internal friction angle obtained by variable angle shear test is similar,and the cohesion force is larger;the size effect of compacted clay basically conforms to Weibull size effect theory,and the modified Weibull size effect formula can describe the size effect of compacted clay better.