Research on characterization of the deterioration of sandstone physical and mechanical properties under mining and water action

Abstract 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, which can be seen, sandstone has a greater impact on mine mining avalanche geological disasters, 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 takes the sandstone before and after the action of mining and water as the research object, analyzes the deterioration characteristics of sandstone hydrophysical and mechanical properties under the action of mining and water, and researches the microstructure of sandstone.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%, and the total degradation rate increased with the increase of the number of dry and wet cycles. 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) The average pore porosity of the quarried sandstone gradually increased at 0, 1, 5, and 10 of the dry and wet cycles, and the sandstone's ability to adsorb water increased，which establishes the microstructural evolution of "mining cracking → water adsorption → water-rock action" model was established. The sandstone undergoes the action of mining and water cycle, the internal structure is weakened faster, and the physical and mechanical properties are deteriorated.