| Xinjiang Liuhuanggou coalfield has the characteristics of simple geological conditions,shallow burial of coal resources,large mining thickness and abundant reserves,but because the area belongs to a typical arid-semi-arid area,the evaporation is large,the rainfall is concentrated,and the surface vegetation is sparse,resulting in serious surface water erosion,longitudinal ditches,large undulating surface fluctuations,large changes in the amount of runoff in the gully rivers,and it is very easy to form flash floods during the rainy season.In addition,due to the lack of planning in the historical mining work,the phenomenon of private digging and random mining in small coal kilns,the shallow coal seams have been mined to varying degrees,forming old empty areas of different sizes,shapes and hidden locations,and there is a strong hydraulic connection with the surface water,which is very easy to cause large-scale water inrush accidents.In addition,due to the impact of global warming,the melting of ice and snow in the adjacent mountains will intensify,and the threat of coupling water damage in the old goaf area of the Liuhuanggou coalfield and the flash flood valley will increase significantly.Based on the research background of the grouting treatment project of water disaster in the old goaf of the Liuhuanggou coal mine,this paper combines the relevant knowledge of engineering geology,hydrogeology and other disciplines,and studies the following contents from the geological and hydrogeological conditions of Liuhuanggou coal mine :(1)Combined with the mine water inflow and Toutun River flow,the characteristics and causes of abnormal water inflow in the old goaf of the mine are analyzed.Mine water inflow shows obvious seasonal variation trend.Toutun River water supplies the old goaf mainly through abandoned roadways,collapse pits,etc.In addition,river excavation also has important influence.(2)Through the comprehensive exploration technology combining geophysical exploration,drilling engineering exploration and hydrogeological test,the solid coal rock,the old goaf and the key water diversion channel are identified,and the T2 goaf is determined as the key water diversion channel.(3)For the exposed solid coal and rock part,the numerical model of slurry diffusion in solid coal and rock stratum is established by using the two-phase Darcy law numerical simulation method.The diffusion law of slurry in solid coal and rock is studied,and the influence of different grouting parameters on grouting effect is analyzed.The results show that when the hole spacing is 4 m,the water cement ratio is 0.8 : 1 and the grouting pressure is 2 MPa,the diffusion effect is the best.Based on this,the curtain grouting scheme of solid coal and rock is designed and the grouting effect is verified.(4)Aiming at the exposed complex old goaf,the concrete plugging technology of goaf is proposed,and the core extraction of inspection hole and simple water pressure test are used for verification.The results show that the plugging effect is remarkable.The stability of the retaining wall is analyzed.The results show that the maximum displacement of the concrete retaining wall is only 0.409 mm,and the displacement is very small.It can be considered that the retaining wall is stable.Therefore,the retaining wall with 6m thickness and C30 concrete can meet the engineering needs.(5)Through hydrological observation and mine water inflow analysis,the treatment effect was tested,and the grouting project was evaluated based on the fuzzy evaluation method.The results show that the water retaining effect after treatment is obvious,which basically isolates the connection between Toutun River water and the old goaf.According to the maximum membership degree criterion,the grouting engineering quality grade can be judged as excellent.This thesis has 50 figures,14 tables and 68 references. |
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