Permeability Evolution Characteristics of Water-Resisting Key Layer Under Water-Force Coupling
The water-resisting key layer has a great influence on the safe mining of coal seam under water body and aquifer.In order to study the permeability evolution law of the water-resisting key layer and the water-resisting performance of the water-resisting key layer during mining,taking the coal mining under the reservoir of the 15130 working face of Xin'an Coal Mine as the engineering background,the water-force coupling seepage test of the water-resisting key layer and the numerical simulation test of the water-resisting performance of the water-resisting key layer were carried out.The results show that the permeability coefficient-strain curve of the water-resisting key layer under bearing compression can be divided into four stages,which correspond to the four stages of the stress-strain curve,namely,the stage of rapid decrease of permeability coefficient,the stage of slow decrease of permeability coefficient,the stage of slow recovery of permeability coefficient and the stage of rapid increase of permeability coefficient.The change of confining pressure in the compaction stage is more likely to cause the change of permeability coefficient of the water-resisting key layer,there is no positive correlation between water pressure and permeability coefficient in the range of 1-2 MPa.The water-resisting key layer above the 15130 working face is bent and deformed under the influence of mining,but on the whole,the water-resisting key layer still has good water-resisting performance.The research results have certain reference significance for coal mining under water.
Water-resisting key layerWater-resisting performanceWater-force couplingPermeability coefficientCoal mining under water bodies