The Study Of Stress Field、Permeability And Gas Migration In Mining Processing Of Sihe Mine

Finding out the stress field、permeability and gas migration regularity is the important guarantee for gas control guidingly and purposefully in the coal mining processing.It makes these studies of laws more difficult because of the complexity of geological conditions、diversity of the mining technique difference of the properties of coal seam.How to explore a strip of effective method and provide theoretical guidance for the the engineering practice acording to different conditions is the pressing problem.In this paper,making the4301working face of Sihe mine as the research object,on the basis of anslysising the original exploration and development information systematically,gas content、pressure、permeability was calculated combined with the principle of hydraulic fracturing in-situ stress measurement,and the spatial distribution pattern of the the original state stress field、gas content、pressure and permeability of the study area was obtained finally.Coal seam roof of different lithologies was studied in laboratory, and the lacation of the main critical stratum and sub critical layer was obtained in combination of the critical layer theory.According features of the Flad3D simulation software and the original reservoir characteristics, this paper simulated changing ragularity of stress field in different propulsive distance、speed and mining height.The results are as follows:The peak value of abutment pressure and t propulsive distance are linear relationship; when the propulsive distance increases, peak value of abutment pressure increases; the peak position changed a little, the area of surrounding rock the damage increases.When increasing mining height,the peak value of abutment pressure increases and then decreases until it tends to stably,and when peak position is away from the coal wall of the working face, the area of the surrounding rock damage increases.The peak value of abutment pressure increases as propulsive speed increases;and when the peak position is near the coal wall of the working face, the area of the damage increases.In the experiment, coal and rock permeability of different confining pressure、repeated loading-unloading conditions was tested,and the stress-strain-permeability relationship was established.The results are as follows: strain-permeability curve lags behind stress-strain curve.In the stage of the plastic deformation of the unloading,the permeability of coal happens a qualitative change. Permeability unloading is2-20times as much as before.Appling of Flac3D seepage model in combining with the gas original occurrence conditions of coal seam, gas diffusion was simulated and analyzed.The results was that with the area of gas diffusion increases as time increases.Relationship of abutment pressure and different gas pressure was established combining gas pressure curve on the basis of anslysising abutment pressure systematically.The results are as follows:the changing tendency of gas pressure curve was similar to the abutment pressure curve, and the peak values of gas pressure is more in stress rising areas. Clearly,the research of coal mining stress、permeability and gas migration laws can provide reference for gas drainage and arrangement of drilling reasonably.