Abstract:The complete stress-strain curve of rock could be divided into pre-failure and post-failure regions according to the peak stress. In general,the pre-failure region of rock shows stability in the mechanical response,which may be described by the classic strength theories,and the post-failure region of rock shows instability,which is difficult to be described by the classic strength theories. The post-failure mechanical characteristics of rock are corresponding to a good many rock engineering,such as underground excavation,pillar,rock burst and so on. Therefore,the research on the post-failure characteristics of rock is of important significance both in theory and in practice. Based on the disturbed state concept theory (Desai,2001),it is assumed that the relative intact state of rock is of hyperbolic form and the fully adjusted state of rock is the critical state of rock failure. A new constitutive model reflecting the post-failure behaviors of rock material is established through defining the expression of disturbance function. A series of uniaxial compressive failure tests about five kinds of rock specimens were performed by RMT-150B rock mechanics test system. The complete stress-strain curves of the five kinds of rock specimens were obtained. The mechanical mechanism of the deformation and failure in rocks is studied using the disturbed state concept. The proposed constitutive model is applied to simulate the post-failure behaviors of rock specimens. From correlative study and analysis,it is shown that the proposed constitutive model can predict,in a certain extent,the mechanical characteristics of rock in post-failure region.