Abstract:The relationships between energy dissipation and strength,energy release and global failure during the deformation and failure of rock mass element are discussed. Under the condition of cyclic compressive load,the energy dissipation and damage variable are calculated and used to fit the damage evolution equation based on the analysis of energy dissipation. The releasable strain energy,dissipated energy,unloading elastic modulus and unloading Poisson¢s ratio are calculated at different loading levels and different loading speeds so that an equation about unloading elastic modulus under complex stress condition is obtained. The global failure criterion of rock mass element is proposed based on the analysis of releasable strain energy and is well accordance with the result of biaxial compressive test on marble. The failure criterion of layered rock mass is proposed based on the analysis of distortion energy and general potential energy of volume;and it is well accordant with the result of biaxial compressive test on layered rock.