Research On State Stress Of Coal Seam And Prevention Of Coal And Gas Outburst

In this paper, regarding the dynamic phenomenon as the background, by applying the following methods: laboratory tests, on site testing, theoretical analysis, numerical simulation and etc., starting with stress condition emphatically, the author discussed the conditions of occurrences, methods of prediction and prophylactic-therapeutic measures'logical parameter of dynamic phenomenons in mines such as the coal and gas outburst. The author expatiated the methods that confirm initial stress in coal seams and wall rocks by setting up present geological structure's model and using geo-stress survey and numerical calculation. Looking on the pressure angle that lying on intensive property of lap seam as the boundary, the author determined moving-enough area, established mathematical model and built tens of numerical simulation's projects according to such four primary factors that impact the distribution of abutment pressure as mining depth, pressure angle, strength of coal mass and thickness of coal seam and the width of coal pillar. By fitting and analyzing the numerical simulation's result, the author gained the characteristic parameters and the computation expression of the distribution of abutment pressure under the each condition of coal seams'occurrence and exploitation and gave the disciplinarian of stress distribution of coal polars in tectonic stress areas. By fitting and analyzing the laboratory simulation test of size effect of coal sample's uniaxial compressive strength and the result of numerical experimentation based on Weibull distribution, the author gained two modulus impacting on the arbitrary coal sample's strength and the regressing formula that calculates the strength of raw coal and coal mass with the normal strength of raw coal. On the base of many projects'numerical simulation, the author confirmed three fundamental factors about pressure relief of drill hole, then gave the expression calculating's breakage (pressure relief) radius with stress in coal seam, strength of coal mass and effective radius of drill hole. The author analyzed the physical test about outburst of drill hole and the result of simulation test synthetically, then gained the critical pressure when the outburst of drill hole happens and discussed the stress conditions that extruding coal and gas burst out. Applying the research findings and probabilistic prediction under pattern recognition in the practice that controls outburst in Pingdingshan 6 Mine, put up the regional prediction of outburst's danger and set up the harnessing measures about gas drainage and pressure relief -well drain drill hole.