Study On Migration Law Of Acid Drinage In Abanoned Coal Mine Under The Coupled Action Of HMC

In order to research the migration law of pollutants in abandon coal mine under multi-field coupling,research the migration law of different ions in rock column under different pressure by rock column test;The change of physical properties of sandstone by acid solution was studied by acid solution immersion experiment.On the basis of experimental rules,the initial parameters such as permeability coefficient,porosity and retardation factor and so on needed to calculate the simulation was calculated.derivation equation based on the coupled action of seepage and stress and chemistry,and the coupling model is solved by finite element software.The results indicate that:(1)The permeability of chloride ions is the strongest under the same pressure,and the adsorption of iron ions is the most serious.The increase of pressure leads to the hysteresis of the ion diffusion process in the water samples,Contains calcium,magnesium ions soluble metal salts dissolve faster;(2)The serious dissolution of calcite and kaolinite mineral particles in sandstone formation under acidic environment is the main reason for the change of pore structure of sandstone,the diameter of the internal pore structure of the rock mass is gradually converted from 100 nm to 1000 nm,the result indicating that the sandstone calcite and kaolinite mineral particles are filled in the pores of 100 nm?1000 nm grade range.The consistency between the simulation results and the experimental results verifies the accuracy of the model,the result also shows that the process of pollutant migration is mainly achieved by convection.The increase of stress will slow down the diffusion of pollutants and the degree of mitigation will decrease with the increase of time.