Influence of immersion-air dry circulation function on deformation and fracture features of sandstone

In the process of impoundment and normal operation of reservoirs, the water level will rise and fall periodically in a planned way. As a result, the immersion-air dry function will lead to the degeneration of mechanical properties of rock mass in variable amplitude zone with time, and then affect the slope stability. Based on these, the immersion-air dry circulation function tests considering the change of water pressure of sand rock are designed, and the deformation and fracture features of rock samples are studied. The test results indicate that the rise or decline of water pressure and the immersion-air dry circulation function have cumulative and irreversible damage to the samples. In the process of circulation, the stress-strain curves of the sand rock samples become slow gradually, the compaction segment gradually becomes long, the gradient of the elastic deformation section decreases gradually, elastic modulus reduces gradually, yield step gradually becomes long, the axial strain corresponding to the peak intensity increases gradually, and the fracture angle of the samples decreases gradually. The stress-strain curves of the sand rock samples show that the samples have a distinct trend of softening. Moreover, the more the cycle times of the immersion-air dry, the more the serious damage to the rock mass. The results of important reference value in the studies on the deformation and fracture laws of the variable amplitude rock in reservoir banks will provide a favorable evidence for the long-term stability analysis of reservoir bank slopes.