Study On Failure Mechanism Physical Experiment Of Aquifers In Northern Shaanxi Typical Mine

Yushenfu mining area is part of the Ordos Jurassic coal, located in the transition zone in northern Shaanxi Province in the Loess Plateau and the Mu Us Desert. this mining area is abundant in coal resources which have the biggest storage volume in China, and is the most important resource base of our country. But the weather of northern Shaanxi province is bad, drought and lack water. where the ecological environment is fragile. The mining area have little aquifer, Salawusu Fm is the main aquifer and the main water supply for the Ecosystem in there. The exploitation of coal resources in mining area will destroy the aquifer and pollute the environment, which not only affect the prodution and live activities of residents but also seriously threat the ecological balance in northern Shaanxi.That related to the sustainable development of Northern Shaanxi and the national economy.Base on the study and surveys of related literature about Yushenfu mining, have classified and generalized the geological environment of coal mine in the this paper. and according this have designed the mining methods in multiple seam. On the basis, Carried out five sets of physical model experiments and three sets of numerical calculation. So that we can get the deformation and failure feature of water and stratum in multi-seam mining conditions of the mine in northern Shaanxi. The research results are as follows:(1)The type of seam in mining area is shallow coal seam with surface thick loose layer. And danage mode of overlying strata is Full-thickness layer cut off. If the first coal layer establishing pillar, the "three zones" in overlying strata is low. mining in under seam will lead to full-thick strata cut off.(2)If the first coal seam establishing pillar when mining. The "three belts" of roof strata developed generated within the low height, Lower seam roof breaking will lead to roof strata cut off.(3)If the first coal seam establishing pillar when mining,There will two parallel shear cracks will generated above the open-off cut and harvest line. and the crack produced in roof strata is tension crack normally. if the first coal layer don’t establishing pillar,the crack will be shear crack.(4)The land above goaf will subside step by step. If there is clay layer, the deepth of strata,the more subside. and the pillar affect rock stratum more the clay layer and aquifer. and the subsidence semblablely without clay layer.