Study on damage and permeability evolution law of strong mining overburden rock
Shendong mining area belongs to the ecologically fragile area.The strong mining disturbance of the mine working face will lead to the damage of the overburden rock and the increase of the permeability evolution,which will cause the ecological environment of the mining area to be seriously damaged.Therefore,this paper takes Lijiahao Coal Mine as the research background,constructs a three-dimensional model of'mining-induced fracture annular body'and its boundary discrimination method.Through numerical simulation,the damage variation characteristics of overlying strata under strong mining disturbance arc analyzed,and the fracture distribution law and permeability evolution law of overlying strata under strong mining disturbance are studied.The results show that the uniaxial compressive strength of the overlying strata in the goaf increases with the increase of the loading rate,and has obvious brittle failure behavior.In the simulation,it is found that the two ends of the working face can be divided into shear failure areas,while the overlying strata of the goaf are tensile failure areas.Under the influence of mining stress,the overlying strata structure,working face advancing speed and working face advancing length are important factors affecting the fracture development.With the mechanical increase of the elastic modulus of the overlying strata in the goaf,the seepage velocity shows a linear increase trend,and the pore water pressure also decreases.The research results are of great significance to the safe and efficient mining of coal mines and the protection of ecological environment in mining areas in China.
strong mining disturbanceinstability failureoverburden rock damagepermeability evolution
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