Study On Influence Characteristics And Water Hazard Prevention Technology Of Lateral High Pressure Ordovician Limestone Aquifer In Deep Seam Mining

With the gradual depletion of shallow coal resources and the shift of mine production to deep mining,the mining of deep coal seams will face a grim situation of more and more complicated geological structure and hydrogeological conditions,especially the existence of large faults,which not only brings adverse effects to the efficient production of mines,but also increases the possibility of mine water inrush.Therefore,in the presence of large faults,the prevention and control of water hazards in deep coal seam mining needs to be further studied.In this paper,the deep area in the east of Xinhe Coal Mine in Jining,Shandong Province,is taken as the research object.By means of data collection,theoretical analysis,laboratory test,numerical simulation and other comprehensive methods,the influence of high-pressure Ordovician limestone aquifer in the footwall of Jiaxiang branch fault on hanging wall 3 coal seam mining and water hazard prevention technology are studied in detail.Firstly,the structural characteristics of Jiaxiang branch fault and its associated faults are introduced in detail from three aspects:occurrence and control,lithologic docking relationship between the two plates and development characteristics.Secondly,the conditions of supplementary runoff and drainage of lateral aquifer are analyzed from the characteristics of lateral runoff of Ordovician limestone and the runoff of lateral Ordovician limestone aquifer.Then,on the basis of fully understanding the lithological changes of fault fracture zone,four kinds of similar materials are selected to simulate the lithology of fault fracture zone,and five groups of samples are made with different proportions,using the principle of similar material simulation.On the basis of Darcy’s law,through the self-designed indoor permeability test equipment,indoor permeability tests under different water pressures were conducted on the samples,and the permeability coefficients of the samples with different proportions and different water pressures were obtained.Furthermore,the permeability variation of the fault zone is understood,and the water-resisting performance of the fault zone is summarized.Finally,the fluid-solid coupling in deep coal seam mining is studied through numerical simulation,and the variation laws of vertical stress,pore water pressure,plastic zone and seepage flow during coal seam mining are understood in detail,and the water hazard prevention technology of lateral high pressure Ordovician lime aquifer is put forward as well,including that setting up coal pillars of faults,exploring hydrogeological conditions,perfecting drainage system,strengthening and sealing small faults by local grouting,and exploring the height of water conducting fracture zone of roof,etc.The research in this paper has guiding significance for safe mining of coal seams on both sides of large-scale faults in North China coalfield.