Post-peak Stress-strain Relationship of Rock Mass Based on Hoek-Brown Strength Criterion

The post-peak mechanical characteristic of rock mass plays a leading role in stability of geotechnical engineering. Based on Hoek-Brown strength criterion and evolutional behavior of strength parameters, choosing major principal strain ɛ1 as strain softening parameter, this paper presents the method of solving post-peak stress-strain relationship. In numerical case, the post-peak stress-strain curves of some rock masses are obtained. The effect of evolutional law of strength parameters σc,m, s and a to post-peak stress-strain curve is discussed, and it's concluded that the greater the residual values of σc,m, s are and the smaller the residual value of a is; the greater the residual strength is and the post-peak stress-strain curve falls more gently.