Stability Analysis Of Underground Reservoir Dam In Li Jiahao Mine

'Rich coal poor water' is the natural resource endowment characteristic in western China.The problem of much water and soil loss resulted from the mining activities in these area.To solve the contradiction problem between large-scale coal mining and water resource loss,Shenhua group proposed a technical way to use underground reservoirs to store underground water.The rock interstices in the goaf resulted by the mining are used to store water in goaf,connecting the coal pillar with the artificial dam to compose the water retaining dam system,constructing mine water storage facilities and water intake facilities and the natural purification of mine water by the rock mass of goaf is fully utilized to realize the reusing of the water.The stable of the dam system consisting of coal pillar and artificial dam are the key factor to protect the coal mine undergroun resercoir from being unsafety.Taking the Li Jiahao coal mine underground reservoir as the background to research,based on the mohr-coulomb criterion knowledge of the elastic mechanics and the COMSOL numerical simulation,the limited head and stability of the artificial dam influenced by the water pressure in the goaf,to research,based on the nonlinear darcy law of seepage mechanics and FLAC3 D numerical simulation,the stability of the coal pillar influenced by the goaf water pressure,and getting the maximum predictive headvalue of the coal pillar.The result shows that: for the stability of artificial dam,under the stress of water storage pressure and overburden strata in goaf,the bottom of the outer surface of the artificial dam is easily to be unstable,the critical head value is 20.3 m which is to be the the warning level,then,as the head increasing,the top of the inner surface becomes unatble with 31.8 m water head as the maximum head.The result of the theoretical analysis consistenting with the numerical simulation results are verified by engineer measuring;For the stability of coal pillar,the water pressure on the side of the pillar can control the width of the plastic zone.And the larger the water pressure is,the smaller the plastic zone width is,which is conducive to the stability of the pillar;when the water pressure gradient of the coal pillar reaches the starting pressure gradient,the coal pillar will be channeled and the leakage would happen.Based on the seepage analysis and the numerical simulation of FLAC3 D,the predicted value of the maximum head of the coal pillar can be 38 m.