岩石三维破裂过程的数值模拟研究

3D NUMERICAL SIMULATION OF FAILURE PROCESS OF ROCK

采用细观弹性损伤模型和有限元计算方法实现岩石三维破裂过程的数值模拟。考虑到岩石非均匀性的本质特征,通过引入简单直观的单元本构模型,采用细观单元材料性质退化的办法,利用位移加载来实现岩石逐渐破裂过程;模拟单轴压缩、单轴拉伸和剪切破裂3种基本试验,得到岩石非线性应力–应变曲线和不同载荷阶段三维损伤破裂演化系列图像;分析细观非均匀性对岩石宏观破裂力学行为的影响。试验研究表明,三维破裂比二维破裂更为复杂,RFPA3D可以有效地模拟脆性材料的三维破裂。

A linear elastic damage model based on finite element method at mesoscopic level was applied to investigate the three-dimensional failure process of rock subjected to various stress loadings. Uniform cube element was adopted in RFPA3D code and rock specimens were discritisized into uniform cube elements with the same size and shape. Mechanical properties in the elements, including elastic modulus and peak strength, were distributed with the specimens following a certain statistical function. In each element, the mechanical properties were homogenous. The elastic moduli and other mechanical properties were weakened when the stresses in the elements are satisfied with the failure criterion. By following a simple elasto-brittle constitutive relation, the complete 3D rock progressive failure was obtained. Finally, three basic experiments were conducted with RFPA3D. Complete nonlinear stress-strain curves as well as facture pictures during damage evolution process were obtained. The numerical simulation results showed that 3D failure process was much more complicated than 2D failure process. It also shows RFPA method is a useful and effective tool to simulate the failure process of heterogeneous materials.