Rock energy evolution under triaxial cyclic loading-unloading compression

摘要

Triaxial cyclic loading-unloading experiments on red sandstones were carried out under 6 kinds of confining pressures on the MTS 816 test system. Total energy density, elastic energy density and dissipated energy density absorbed by rock specimens under different confining pressures were obtained. Evolution process of energy accumulation and dissipation and confining pressure effect of the distribution law were analyzed, to reveal the energy conversion mechanism from rock deformation to rock failure. The energy conversion equations in different stress-strain stages were established. The results showed with the rise of confining pressure, characteristic energy density of the rock increased in a power--exponent form, and the energy storage limit density of the rock increased faster than the maximum dissipated energy density. The confining pressure increased the intensity of energy input, improved the efficiency of energy accumulation and inhibited the degree of energy release.