砂卵石-砂土复合试样大三轴数值试验及验证

Numerical and Experimental Study of Large-Scale Triaxial Tests on Sandy Cobble-Sand Samples

基于北京地下直径线典型砂卵石地层试样的大型三轴排水试验结果,利用通用有限元软件ABAQUS采用Mohr-Coulomb本构模型对复合土样三轴试验的破坏过程进行了数值模拟,基本上再现了土样三轴试验的偏应力-应变关系,说明数值计算能够有效地模拟土样的三轴试验。在此基础上,通过不同砂层厚度试样的数值试验,探究了砂层对复合试样强度和破坏规律的影响。计算结果表明:试验围压,试样中砂土的位置及厚度对于砂卵石-砂土试样的强度及破坏模式有显著的影响。

Based on the results of large drained triaxial tests on typical sandy cobble strata in Beijing Rail Underground Transit Line,the failure process of triaxial tests is simulated using finite element software ABAQUS with Mohr-Coulomb constitutive model,the partial stress-strain relationship of sandy cobble-sand samples is generally reproduced,indicating that numerical simulation of triaxial tests can be modeled perfectly. As a result,the impact of sand on the strength and failure law of specimen is explored by simulating the numerical experiments on samples with sand layer of different thickness. The computed results show that the confining pressure in testing,the location and thickness of sand in the samples have a significant impact on the strength and failure mode of sandy cobble-sand samples.