Deterioration characterization of sandstone physical and mechanical properties under mining and water action

Mining geological disasters occur frequently in Guizhou, with mine mining and rainfall-induced avalanche geological disasters mainly, the investigation concluded that the hard rock of the overlying slide body is mostly sandstone, and it is crucial to study the physical and mechanical properties of sandstone under the action of mine mining (hereinafter referred to as the action of mining) and water action. The paper analyzes the deterioration characteristics of sandstone hydrophysical and mechanical properties under the action of mining and water. The main research results are as follows: (1) The water absorption rate of sandstone increased by 0.056% under the action of mining, the water absorption rate of sandstone increased with a good exponential relationship under the action of dry and wet cycles, the swelling rate of sandstone increased by 0.3% under the action of mining, and the index of disintegration resistance decreased by 0.3% in 5 cycles; (2) The damage rate of uniaxial compressive strength of sandstone after being subjected to mining was 6.367%. The total deterioration rate increases with the number of wet and dry cycles, the stage deterioration rate and the average stage deterioration rate first decrease and then increase, and the degree of fragmentation gradually increases; (3) According to the microscopic test results, the microstructural evolution of "mining cracking → water adsorption → water-rock interaction" model was established.