Study On The Rule Of Ground Movement And Deformation In Steep Coal Seam Mining Of Urumchi Mining Area

Urumchi mining area is the largest steep coal seam mining area in China. The surface collapse and the cracking can be found everywhere in the mining area after steep coal seams mining for several dozen years. The collapse is under the unsteady-state situation. It develops and continues by the ways of sudden and intermittent activities along with depth portion coal bed unceasing mining. People lived in the mining areas and the near areas have suffered severe damage in the accident. Therefore, studying on the surface subsidence rule and prediction of Urumchi mining area is quite urgent.The subsidence law of steep coal seams mining is very difference from flat coal seams mining or gently inclined seams mining. The coal seams inclination angle change in which multitudinous influence factors has become one of primary factors affecting the steep coal seam mining which ground displacement and deformation. This paper takes the Urumqi mining area as the example of study and bases on the inclination angle change. Selecting the Tiechanggou mine field(45°) , Liudaowan mine field(65°) and Jiangou mine field(84°) as the numerical simulation prototype of the most typical representative mine field of Urumchi mining area. Respectively building the two-dimensional finite element model with the coal inclination angle of 45°,65°and 84°,and researching the overburden strata stress and the displacement variation law of underground mining caused by steep coal seam inclination angle changing in case of the horizontal section top-coal caving with the ANSYS finite element software. According to the result of the research, with the increase of coal seam angle, the ground movement and deformation values decreased gradually, and the influence also becomes weak slowly.This paper designs the steep coal seam mining subsidence prediction system with the VB. The system can predict the five dates of surface movement and deformation such as surface subsidence, slant, curvature, level movement and level deformation. And outputting the every ground displacement and deformation prediction curve of inclination main section, and calculating automatically the maximum and minimum of ground displacement and deformation. At the same time it can output the ground displacement and deformation values of any point on the inclination main section. Furthermore the system can simulate dynamically the entire mining subsidence developing process, and output the dynamical curve of ground displacement and deformation. The system can output the dates of prediction result, but also output the prediction curve, with intuitive and practical features. A practical example shows that the system has the higher accuracy and a certain practical value.