Post-peak strain softening model of rock based on degradation angle.

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. [ABSTRACT FROM AUTHOR]