脆塑性岩石破坏后区应力跌落效应数值模拟

Numerical simulation on post failure stress-drop of brittle-plastic rock materials

采用三轴试验和数值模拟研究了岩石类脆塑性材料的应力跌落效应,并用塑性流动因子λ来描述应力跌落效应。为简化计算,给出了一种应力陡降过程中伴随的非零应变增量的工程近似处理方法,基于此针对性地编制了处理脆塑性材料应力跌落的有限元分析程序代码。数值模拟结果验证了塑性流动因子λ以及该近似处理方法的有效性。

Uniaxial or triaxial compression test of cylindrical rock specimens using rock mechanics testing machine are basic experimental method to study the strength and deformation characteristics of rock and the development process of rock fracture.Extensive literature review has been conducted on this issue.Meanwhile,experimental and numerical studies have been conducted on the stress-drop effect on the brittleness of rock materials.A plastic flow factor is proposed to describe the stress-drop effect.For simplicity purposes,an engineering approximation approach has been proposed to evaluate the stress-drop with a non-zero strain increment.Numerical simulation results validate the effectiveness of the plastic flow factor as well as the engineering approximation approach.Based on the results in this study,finite element code can be programmed for brittle materials with stress-drop,which has the potential to be readily incorporated in finite element codes.