The Laws Of Roof Movement And Surface Deformation In Reverse Overlying Strata Area At Gaocheng Coal Mine

It is the underground mining of the coal resources that makes the balance between environment and buildings(structures) in mining area destroyed. The theory of mining pressure, the surface subsidence and expected theory has been relatively mature, but there are few research results on strata movement and the surface deformation by mining under gliding structure zone.With 21021 mining face and 25001 mining face of Gaocheng coal mine as research object, this thesis measured the subsidence caused used by mining under gliding structure zone where overlying is reverse inclined through establishing observation station of surface movement. According to the data of observation station, we obtained the angle dimension parameters of ground movement by using the points of feature and probability integral combined method using least squares curve fitting. The results show that coal mining has a large range of surface subsidence, surface movement tempestuous, surface subsidence rate large, the displacement angle small, the surface damagement severe, and so on, and also prove that the largest sinking point leans the direction of raise entry of working face.This paper regarded geological mining condition as prototype and adopted the method of analog simulation experiment and deformation law of rock strata displace and surface at reversed inclined overlying strata mining area with the influence of slide structure. The test results show that the shape of caving zone is parabola shape; curve subsidence zone is located in the upper left direction of mining face; the roof of working face drop entry will slide and fracture; finally, largest sinking point leans to the direction of working face raise entry.The influence of reversed overlying strata angle to the law of rock strata displace was studied by UDEC numerical simulation. The results show that the range of rock strata displace and the largest sinking point leans to the direction of drop entry of working face when the angles of overlying strata are 10 and 20; the range of rock strata displace and the largest sinking point leans the direction of raise entry of working face when the angles of overlying strata are 30, 40 and 50; the range of rock strata displace and the largest sinking point leans to the direction of drop entry of working face when the angle of overlying stratais 60. The main reason is that when the angle of overlying strata change, the pressure of rock strata bedding surface is different. When the angle of rock strata is smaller, the bedding surface is mainly affected by the normal stress and at the same time rock strata occurs bending and sinking. When the angle of rock strata is larger, the bedding surface is mainly affected by shear stress, and at the same time, rock strata slides and even fracture.This study has guiding significance on safe mining, predict and contral the ground subsidence and reduce mining damage of mining under gliding structure zone where overlying strata is reverse.