Research On Settlement Failure Control Technology Of Key Water-Barrier Layer In Thick Coal Seam Mining Under Shajin River

In the actual mining process of coal mines,coal mining under water bodies is a common work,and compared to coal mining under general nature,the safety factor of coal mining under water bodies is significantly lower.Under certain conditions and constraints,coal mining under water bodies can cause deformation of the underwater rock structure.Due to the influence of water pressure control,the stability factor and safety factor of coal mining will be threatened,so the coal mining under water bodies will be affected,It is necessary to fully plan for water permeability and sand break accidents.In order to achieve safe mining of coal resources,the specific research results are as follows:Fully collect the existing geological and physical and mechanical properties of the roof and floor slabs in the mining area,analyze and study the water abundance and boundary recharge conditions of the main aquifers within the scope of the mine field,analyze the mine water filling conditions in areas where coal mining is greatly affected by surface water,analyze the mining water filling factors of the working face and predict the mine water inflow in areas with strong phreatic water content in the Quaternary alluvium that are highly threatened by water hazards,Quantitative assessment of water source threats and channels.In order to determine the height of the water conducting fracture zone and ensure the safe mining of coal seams,similar physical model simulations and empirical formulas are used to calculate the height of the water conducting fracture zone respectively.To verify the formula method to calculate whether the No.15,19,51,and 18 coal seams pose a serious threat to underground mining,the size of the full height waterproof and safe coal(rock)pillar for mining coal seams in the river area is calculated according to the "three lower" mining regulations,In order to reduce the risk of safe coal(rock)pillar size caused by the calculation error of the development height of the water conducting fracture zone,and ensure the safety of mining coal seam resources seriously threatened by the upper water body,a safe coal(rock)pillar retention method based on the integrity of the key aquifers was proposed for the first time.Consider the lithologic combination of the coal seam roof as an important factor for the safe retention of coal(rock)pillars,and ensure that the key aquifers on the coal seam roof are complete,enabling safe recovery.The finite difference method is used to simulate and study the surface subsidence law after coal mining in the third mining area,systematically analyze and study the surface subsidence data after mining in the working face,study and master the movement law of the roof rock in the third mining area,predict the surface subsidence after subsequent mining in the working face,and provide scientific basis for formulating safety measures for coal mining and protecting surface water resources in advance.A comprehensive and systematic analysis of the water filling sources and channels in the mine has been conducted,and a comprehensive prevention and control technology for water disasters in the upper and lower parts of the well has been developed for 3228 working face research,including controlling mining height and mining speed,draining roof water,detecting and sealing poor boreholes,establishing a surface hydrological monitoring and early warning system,and improving the drainage system.Through practice,it has been verified that the water disaster prevention and control measures for mining shallow buried deep and thick coal seams under the river channel are scientific and effective,and the calculation of mine water inflow is accurate and reliable,achieving the safe mining of coal resources under the Shajin River river channel.According to the numerical simulation results,after the completion of mining using the water hazard prevention and control mining technology,a surface subsidence observation station is established for the 3228 working face that has been mined,and the mining subsidence amount is measured;Based on the actual surface subsidence observation values of Working Face 3228 and the mining subsidence theory,the mining subsidence coefficient is calculated to predict the surface subsidence value of the river channel after mining in Working Face 3200,providing a scientific basis for protecting surface rivers and groundwater resources.This thesis has 44 figures,15 tables and 78 references.