基于退化角的岩石峰后应变软化模型

摘要

为反映围压对岩石峰后脆性的影响,提出了描述岩石峰后软化行为的新参数,即退化角。对山西含碳泥岩三轴试验数据拟合表明,退化角与围压呈线性关系。推导了岩石峰后软化中等效塑性剪切应变与退化角之间的关系式,提出了基于退化角的岩石峰后应变软化模型。在FLAC环境下,利用Fish函数方法开发了相应的数值计算程序。数值算例研究了山西含碳泥岩在不同围压下的应变软化过程,模拟结果与试验数据规律基本一致,表明：退化角能较好地描述围压对岩石峰后脆性的影响;建立的峰后应变软化模型合理而可靠,为岩石峰后软化过程模拟提供了新的思路。%To reflect the effect of confining pressure on the brittleness of the post-peak rock,the degradation angle of post-peak strength of the new parameter was presented.Based on the test data for mudstone of Shanxi in triaxial compression,the linear relationship between the degradation angle and the confining stress was founded.The law between the equivalent plastic shear strain and the degradation angle was presented,and the strain softening model of rock based on the degradation angle was set up.Fish function method within FLAC was used and the numerical code was developed.In numerical case study,the strain softening processes under variable confining pressure for mudstone of Shanxi were modeled.The simulating results accord with experimental data.Those show that the degradation angle is an effective parameter to reflect the effect of confining pressure on the brittleness of the post-peak rock;the model in this paper is reasonable and can be used to model the strain softening processes of post-peak strength rock.