岩石细观损伤演化与损伤局部化的数值研究

应用岩石破裂过程分析系统(RFPA2D),通过对非均质岩石试样在单轴压缩下损伤演化过程的数值模拟,研究了岩石变形破裂过程中的损伤演化和损伤局部化行为·模拟结果表明岩石的非均匀性及其结构尺度对损伤局部化模式有很大的影响·岩石在压缩条件下的损伤局部化主要有三种模式:平行剪切带,单一剪切带和共轭剪切带·在局部化剪切带出现时,材料所表现出的高度非线性主要是剪切带内的损伤汇合连通滑移引起的,而在剪切带外主要发生弹性卸载回弹作用·岩石应力应变曲线峰值后区的力学响应主要取决于细观单元变形的结构效应,而损伤局部化正是造成应力应变峰后曲线具有尺度效应的原因,非均质岩石的全应力应变曲线不能纯粹地认为是岩石的材料性...

Numerical Investigation on Mesoscopic Damage Evolution and Localization Behaviors of Rock

Heterogeneous rocks in uniaxial compression was numerically simulated to investigate their damage evolution and localization behaviors occurred in rock failure process using RFPA~(2D) code. The numerical simulations showed that the heterogeneity of rocks and structural size of rock specimen affect greatly the damage localization patterns of rock specimen and that there are mainly three damage localization patterns in rock failure under compression, i.e., parallel shear bands, single shear bands and conjugate shear bands. The remarkable nonlinearity of deformation combined with the occurrence of shear bands is mainly due to the coalescence and slippage of cracks, while elastic snap-back occurs beyond the shear bands. In addition, the post-peak response portion of stress-strain curve depends mainly on the deformation of the structural effect, and the damage localization just means that the descending portion of the stress-strain curve of specimen is size-dependent. So, the stress-strain curve of rock can not be regarded as a pure material property.