EXPERIMENTAL RESEARCH ON FAILURE AND ENERGY DISSIPATION CHRACTERISTICS OF THE SANDSTONE1)

The effects of unloading rate under different paths on the mechanical properties of sandstone and the energy dissipation in the failure process have been analyzed by the triaxial unloading test The results are as follows: the axial deformation plays a leading role in the elastic phase of the whole process stress-strain curve. And in the elastoplastic stage, the increase of the hoop strain is greater than the axial strain’s In the confining pressure unloading stage, the smaller the unloading rate, the greater the flexibility of the strain. At the same time, the deformation of the rock sample is insufficient, which is an obvious brittle failure characteristic. The dissipative energy under the constant principal stress difference path is 1.35 times than it is under the constant axial pressure path The larger the unloading rate, the smaller the elastic strain energy of the rock sample.