Influence Of Gas Pressure On Coal Burst And Its Prevention

The occurrence of rock burst is the result of multi-factor coupling.With the increasing of mining depth,the number of high geostress and high gas mines will gradually increase.The presence of gas in the coal seam will have a huge influence on the mechanical properties of the coal mass,which will affect the static load distribution and the propagation of the dynamic load.Several research methods are employed to study the influence of gas pressure on coal burst in this paper.The change of mechanical parameters of coal mass under triaxial compression with different gas pressure conditions is simulated and find that with the pore pressure decreasing,the triaxial strength,cohesion and friction of the sample will gradually increase.Based on the Mohr-Coulomb criterion and the effective stress principle,it is concluded that the uniaxial strength of sample increases with the decreasing of gas pressure.Taking the 6124-1 working face of Haishiwan Coal Mine as the research background to study the effect of gas pressure on the dynamic and static load of the stope.The results are as following:?1?The relationship between gas pressure and the distribution of support pressure was build.With the gas pressure decreasing,the peak position of the support pressure approaches the coal wall,and the peak value of the support pressure increases,and a simulation test is employed to prove it;?2?The frequency of micro-seismic events gradually increases with the decrease of gas pressure.Using the Dynamic module in FLAC^3D,the propagation law of dynamic loads under different pore pressure conditions is simulated.The results show that the effect of dynamic load on the vertical stress of the right of the roadway is greater than that of top and bottom sides,and the effect is enhanced as the pore pressure decreasing;with the decreasing of the pore pressure,the vertical displacement of the roof and floor gradually increased,while the vertical displacement increase of the two sides of the roadway remained unchanged;the horizontal displacement of both sides of the roadway gradually increased,while the horizontal displacement increment of the roof and floor remained almost unchanged.The above research results have been applied in Haishiwan Coal Mine to build an effective Monitoring and prevention system for rock burst.There are 62 figures,13 tables,and 91 references in this paper.