| At present,there are two main problems in the mining of filling method in coal mine:the high cost of filling and the shortage of filling materials.In view of this problem,this paper takes a kind of super absorbent resin with low price and wide source as the filling material of goaf,and studies the basic properties of super absorbent resin filling material and the actual effect after filling goaf by experimental and theoretical methods.The main conclusions are as follows:Firstly,the properties of superabsorbent resin were studied.The results showed that the average water absorption ratio of superabsorbent resin was 408.2.When the water content is 300 times,the slump is 293;when the water content is 1700 times,the viscosity of the solution is 16S.Under the condition of airtight and normal pressure,the super absorbent resin material did not appear water separation in 48 days.The results show that the super absorbent resin has high water absorption,good fluidity and stable properties.The seepage of superabsorbent resin in the fracture of surrounding rock is simulated,and the volume compression is analyzed.The results show that the seepage distance of 0.5MPa and 0.7MPa is 14.9 cm and 15.1cm respectively,and the compression of super absorbent resin is 4.6mm when the pressure is 2.39mpa,which is about 4.8%of the original height.COMSOL is used to simulate the seepage of superabsorbent resin in rock fractures.The results show that the pressure of superabsorbent resin tends to be stable in the 15th year,and the volume of superabsorbent resin lost through seepage accounts for about 0.0042%of the total filling volume in one year.It shows that the volume of the goaf filled with super absorbent resin will not shrink.The stress and surface subsidence of superabsorbent resin after filling in goaf are analyzed by theoretical method.According to the assumption of Winkler elastic foundation beam,the roof deflection equations are established,and the combined roof deflection subsidence value is 75 mm.The calculation results show that the maximum surface subsidence of full filling mining in the goaf with super absorbent resin is 276mm.The calculation results show that the roof and surface subsidence can be effectively controlled by filling the goaf with super absorbent resin.According to the strata condition of 30303 working face in xuemiaotan coal mine,the flac-3d calculation model is established to analyze the surface subsidence of super absorbent resin material at different filling heights.The results show that the maximum subsidence of super absorbent resin is 0.26M in 30 years,and the maximum subsidence of surface is 0.15m.The filling height of super absorbent resin material is 5.5m,which is more economical and reasonable. |
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