Study On The Law Of Coal Subsidence Under Different Dip Angle And The Early Warning Of Disaster

The surface subsidence caused by coal mining is the bottleneck restricting the sustainable development of mining area economy and ecological environment.Coal seam mining with different dip angle produces different coal mining subsidence characteristics.In this paper,based on the geological prototype of Hongshiwan Coal Mine,the law of coal subsidence under different dip angle is studied by numerical simulation experiment,similar material simulation experiment,multiple regression analysis and theoretical analysis.The main conclusions are as followings:(1)The model of coal mining subsidence with different dip angle was established,and the influence of key stratum position,fault tendency,joint and stress on coal mining subsidence was studied.It is considered that the farther the key layer is from the surface,the more severe the surface subsidence is;the fault and extrusion stress reduce the surface subsidence;and the joint and tensile stress aggravate the surface subsidence.From gently inclined to middle inclined to steeply inclined coal seam,the symmetry of surface subsidence and horizontal displacement form is getting worse and worse,the maximum value of surface subsidence is shifted from the intersection of normal direction and surface to downhill direction,and the shape of water diversion fissure zone is changed from saddle shape to trapezoid.(2)An early warning model for coal mining subsidence is established.Coal mining subsidence disaster refers to the sudden change process of coal mining subsidence affecting ecological environment from acceptable to disaster formation.When the working face is pushed to a certain distance,the mining disturbance will affect the surface and cause the surface to sink significantly.According to the relationship between mining strength and maximum allowable surface subsidence value,an early warning model of the No.I kind of coal mining subsidence is established.According to the relationship between mining strength and development height of water-conducting fissure zone,a disaster warning model of the No.II kind of coal mining subsidence is established.(3)Taking working face 010507 of Hongshiwan Coal Mine as an example,the reliability of early warning model of coal mining subsidence disaster is verified.Once the working face propulsion length is more than 140 m,the No.I kind of coal mining subsidence will occur.When the working face is pushed to 600 m,the maximum height of the water-conducting fissure zone is 180 m,and then the working face continues to push,while the height of the water-conducting fissure zone is basically unchanged.Because the distance from the roof of coal seam to the key layer of main water insulation is much larger than the maximum height of the water-conducting fissure zone,the No.II kind of coal mining subsidence disaster will not occur.