Risk Assessment Of Water Inrush From The Floor Of The Working Face Based On The Reconstruction Of Taihui Aquifer In Zhangji Mine

The shallow coal resources in Huainan mining area with multiple coal seams are gradually exhausted.Coal mines mainly mine deep coal seams,most of which have been mined to the-800m level currently.The structure of Huainan coalfield is complex after multi-stage tectonic movement,and the complex syncline is the main structural feature of the coalfield.The aquifer system in the study area is affected by tectonic movement and changes its structure,especially the large number of strike normal faults formed in the Himalayan period make the study area form a group of roughly parallel stepped structures,which is the most obvious transformation of the aquifer.This paper takes the 1613A working face of the Xisan 1 coal mining area in Huainan coalfield Zhangji coal mine as the research object,systematically collects and arranges the hydrogeological data of the mine and mining area,combines the hydrogeological supplementary exploration results,the actual exposed hydrogeological data,and underground ash Rock drilling water production data,using a combination of data analysis and prediction,and numerical simulation to explore and manage the vertical water-conducting structure of the 1613 A working face,and use simulation to verify the effect of grouting reinforcement treatment.And evaluate the risk of water inrush from the working face.The research results are as follows:(1)The upper mining area of Xisan No.1 coal is a fully concealed coal-bearing area,and the roof of the mining area is all in the old roof middle-fine sandstone direct covering area,and the direct floor change of the No.1 coal is more obvious.The coal and rock layer in the mining area is a monoclinic structure,mainly developed by normal faults.The major faults that have a.greater impact on the mining of the working face are:F1613A77,F1611A76,F1313A78,and F1316A78-1.Limestone aquifer is weak to strong water-rich and unevenly distributed,which is the main water filling source for'No.1.coal seam mining.(2)Aiming at the occurrence of water emergence during construction under directional drilling under 1 coal floor C33 ?,the water level,water quality,water temperature and water pressure are used to comprehensively analyze the water source mainly from Ordovician limestone water,and comprehensive drilling and drilling exploration schemes are used to delineate the water vertical guide The water channel is an elliptical area with a length of about 52m and a width of about 33m.Up and down well grouting is adopted to strengthen the vertical guide water channel.(3)Use FLAC3D numerical simulation software to organize and count the formation information to establish a three-dimensional model of the 1613A working face.The simulation results show that when the stoping advances to 120m before grouting reinforcement,the plastic failure area of the floor communicates with the vertical water channel.1 Coal mining poses a water hazard threat;The plastic failure area of floor in the mining process after grouting reinforcement is not connected with the vertical water diversion channel,which does not pose a threat to water inrush.(4)For the water channel discovered by the explorationthe five figure double coefficient method was used to evaluate the water inrush risk of the vertical water channel discovered by the exploration of the ash aquifer in the coal seam floor before and after grouting treatment.The depth of floor mining damage before grouting was about 24m,The damage depth of the bottom plate is significantly reduced after grouting;The thickness of the protective layer of the working face floor is about 50 m before grouting,and the thickness of the protective layer increases to 80 m after grouting.Through the comprehensive analysis of the pressure coefficient and water inrush coefficient index,the pressure coefficient of the working face before grouting is less than 0,and the water inrush coefficient is greater than 1MPa/m,and the working face mining faces a greater risk of water inrush.The pressure coefficient of working face after grouting treatment is greater than 0,and the water inrush coefficient is 0.08MPa/m,which is less than the requirement of 1MPa/m for the complete rock section required by the specification.The grouting treatment effect is obvious,and the coal seam mining is safer after grouting treatment.Figure 37 Table 18 Reference71...