黄土拉伸试验及其破裂过程仿真分析

Tensile test and simulation analysis of fracture process of loess

Q3黄土的单轴拉伸试验表明,黄土的抗拉强度值很小,在拉张应力作用下会发生突发性的脆性破坏,断裂面粗糙,且基本垂直于拉应力方向。借助数值分析软件RFPA,对黄土的整个拉张破裂过程进行了仿真分析,捕捉到了黄土在拉张应力作用下内部裂纹的扩展与演化过程。结果表明,黄土的拉张破裂过程可以分为两个阶段,即线性变形阶段和裂纹的形成、扩展与贯通阶段。黄土体内部裂纹的萌生、扩展及贯通会在很短时间内完成,即黄土在拉伸应力作用下的破坏是突发性的,属于脆性断裂。单轴拉伸试验结果与数值仿真分析结果具有较好的一致性。

The uniaxial tensile test of loess shows that the tensile strength of loess is very small; and under the action of tensile stress, the burst brittle rupture will occur on loess sample, with the coarse fracture plane and the direction vertical to tensile stress. By using the numerical analysis software RFPA, the whole tensile fracture process of loess is simulated; and the expansion and evolution of internal cracks in loess under the action of tensile stress is captured. The results indicate that the tensile fracture course of loess can be divided into two stages, one is the linear deformation stage, and the other is the stage of formation, expansion and evolution of cracks in loess, which can be completed in very short time. So the broken of loess under the action of tensile stress is paroxysmal, which belongs to a brittle fracture. The result of uniaxial tensile test on loess is very consistent with that of the numerical simulation analysis.