The Study On The Damage Mechanism Of Water-resisting Layer In Shallow Buried Coal-seam After Mining Operation

Shanxi Yulin has become the focus of the development of China’s coal key area, which has a lot of coal resource; coal seam buried shallow and stable storage conditions. But with coal mining, shallow aquifer has been destroyed, cause water lowering in aquifer, springs and lakes dry up, river flow is reduced and the drying up river. The environment has been destroyed and can not be repaired. So the biggest development technical difficulties of shallow coal seam covered with thin bedrock is balance between mining of coal resources safety and Protection of water resources, Achieve the purpose of "water-preserved-mining". But thin bedrock have various thickness, it have two types:the typical shallow seam and proximal shallow buried coal-seam. Caused different height of water flowing fractured zone. This paper use#3coal seam to analysis the height of Water Flowing Fractured Zone, which is primary mineable coal bed in YuYang Mining Area. The thickness of#3coal seam work face is3.2to3.9mSeam hosted in jurassic yanan group, Buried depth is about157m, Average of coal seam dip angle generally is0.5°to1°, Average of coal seam thickness is3.5m, hosting occurrence stability and simple structure.The research area have simple geological structure, Moderate hydro geological conditions, flat terrain and20m thick quaternary Aeolian sand bed, has good mining conditions. Mining area is adjacent to southern maowusu desert and covered by desert plains in the east, the western landscape to semi-fixed sand dune. Covered the desert over70%. Rainfall in the area is scarce. Groundwater resources are relatively poor. Ecological environment is very fragile. The mining of shallow coal will affect the aquifers, caused mine collapse of water damage and destroyed the precious water resources. So research height of fractured in shallow buried coal-seam is particularly important to water-preserved-mining.In the process of analysis mining thick wind-blown sand shallow seam, using theoretical analysis to judge key strata’s position, According to law of deformation after mining, establish quantitative relation of maximum ground subsidence the height of Water Flowing Fractured Zone and overburden’s tensile deformation rate, derived calculation formula of overburden’s tensile deformation rate, gived a new theoretical prediction way for ensure height of Water Flowing Fractured Zone. Combined with similar simulation and numerical simulation to determine the height of Water Flowing Fractured Zone after mining, contrastived and analysised result of theoretical calculation, similar simulation and numerical simulation, Three results were basically identical, so verified reliability of the theoretical computing results. Achievements provided a new direction for theoretical calculation of water-preserved-mining...