| As the focus of coal production in China continues to shift to the west,the western mining areas will play an increasingly important role in ensuring national energy security.It is urgent to extract coal economically and efficiently and realize scientific mining under the premise of ensuring the allowable range of safety and environmental capacity.The prevention and control of coal mine water damage under complex geological conditions is an important problem restricting coal mine safety.The author for sheep field bay east ningxia mining area coal mine complex hydrogeological conditions,through the geological survey and hydrogeological overlying rock fissure seepage model build,analog simulation,the characteristics of surrounding rock stress evolution analysis,methods of coal seam floor water bursting coefficient analysis,mining system is studied under the influence of formation mechanism of coal mine water hazards in sheep field bay and initially formed a sheep comprehensive prevention and control management system of coal mine water hazards in a bay.The research results have important reference significance for the prevention and control of water damage in coal mines under complex hydrogeological conditions.The main research results are as follows:(1)The hydrogeological conditions and coal seam burial conditions of yangchangwan coal mine are summarized.Geological survey,borehole pumping and other geological exploration techniques are used to study the distribution and general situation of aquifer and water body damaged or affected by mining in mine and working face,as well as the distribution of goaf water in mine and surrounding areas.The survey data show that the hydrogeological conditions and mining conditions of yangchangwan coal mine are very complicated.Yangchangwan coal mine is the main water filling source two straight ROM group sandstone at the bottom of the section to two groups of water and coal roof sandstone aquifer structure cracks filled with water,six coal seam mining the main water filling source for quaternary system aquifer water,coal two to eight groups grit sandstone aquifer water between coal strata and coal magnetic kiln fort expansion of each well section(section C28)goaf water and Y142 goaf water.(2)Reveal the macroscopic mechanical properties of coal and rock considering complex hydrological conditions.The natural and full water compression experiments were carried out to compare the macroscopic failure characteristics of coal and rock samples under different conditions.The unstable failure stage of water-filled coal rock is not obvious,the stress drop time of water-filled coal sample is long,and the curve shows the change of double-peak with concave shape.In addition,the cracks in the saturated coal rock are more likely to occur multiple penetration and more fracture.The characteristics of ae signals of the saturated rock samples were severe,and the ringing count and energy rate were higher,indicating that the coal rock was destroyed in several stages due to the saturated water.With the help of similar simulation experiments and thermal infrared radiation monitoring,the evolution law and failure process of the fracture field of coal and rock mass under the macroscopic scale were simulated,which provided scientific basis for the prevention and control of the subsequent roof water damage.(3)The seepage law of groundwater and the stress evolution characteristics of overlying surrounding rock in the real mining environment of yangchangwan coal mine are determined.MODFLOW software is adopted to establish the three dimensional seepage model has high precision,using VB language to realize the simulation of real condition of groundwater movement,on the real conditions of coal mine water inflow forecast,calculation results show that because the drainage level,through the rock,mining area,the working face water inflow during the recovery period of stoping are different.If the water prevention and control measures are not taken in the mining area before stoping,the maximum amount of water inflow in one area during stoping is 81580.84m~3/d,and the minimum amount is 617.60m~3/d.The maximum water inflow in the two zones is 35040.02m~3/d,and the minimum is733.80m~3/d.(4)The paper discusses the types of coal mine water damage in Yangchangwan coal mine.The complex hydrogeological type dominated by mine water inrush and the complex hydrogeological type dominated by goaf water distribution in well no.2 are obtained,which is enough to indicate that mine water inrush is the key to water prevention and control in well no.1 of yangchangwan coal mine and goaf water is the key to water prevention and control in well no.2.According to the drilling data of yangchangwan coal mine and the evaluation method of water inrush coefficient of coal floor,the interpolation calculation method of water inrush coefficient is modified based on kriger interpolation method.The results show that the new method can significantly improve the calculation accuracy of water inrush coefficient,and predict the north<west<southeast of the floor water inrush danger area of yangchangwan mining area,which provides the research foundation for the follow-up prevention technology.(5)To form a comprehensive water disaster prevention and control technical system under complex conditions in yangchangwan coal mine.To carry out hydrogeological drilling,geophysical and geochemical exploration;Through pumping(draining)water test,well logging prediction of working face and mine water inflow,master its changes and rules,summarize various water prevention and control methods and application effects,the roof sandstone water drainage technology is formed,and the comprehensive prevention and control system of coal mine water damage is preliminarily obtained under the special hydrogeological conditions of yangchangwan coal mine.The related research results can provide theoretical guidance for the comprehensive prevention and control of water damage in similar mining areas. |
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