| At present, the mine total of high gas, coal and gas outburst has exceeded six thousand, account of half in Chinese. With increasing of mining depth and mining intensity, the difficulty of gas control is more and more big. Because most of the coalfield methane existing "three high-low" features.The plasticity, gas adsorption and gas storage of coal seam is high, gas pressure, gas saturation and gas permeability of coal seam is low. It is non-ideal of gas pre-drainage compared to America and Australia, gas extraction is only twenty-three percentage in China, and gas extraction is over fifty percentage in America and Australia. In view of this, Zhao Yangsheng team of TaiYuan university of technology has developed drilling rig of special high-pressure hydraulic cut seam and corollary equipment with continuous steel tube as the core technology since 1998, it is systematic to study the effect of hydraulic cut seam improving gas drainage of low permeability by laboratory experiment and industrial test. Although it has many times industrial test of pressure relief of coal seam by hydraulic cut seam, the report of stability of working face after hydraulic cut seam has never saw. Coal seam through hydraulic, the integrity of coal seam is damaged. Whether effectting the stability of surrounding rock in the working face is always an unanswered question. This paper bases on the application in 9804 working face of KaiYuan coal mine of YangMei group, to study the influence of working face wall and roof stability by hydraulic cut seam. The conclusion has vital significance to coal and gas outburst in safety and efficiency. The article mainly do some research from the following several aspects: (1)This paper describes the high pressure water jet cutting coal seam, it makes pressure relief of slot around and discharging pressure of gas emission in a short time. Especially in coal mining, the coal of slot around is further destruction, causing the coal seam second discharging pressure and analyzing the gas migration rule after second discharging pressure.(2)Analyses low of the abutment pressure changing in cut seam area, it has effect to gas drainage in front of working face. When working face advances to cut seam area, analyzes the stability of surrounding rocks. Main analysis the coupling relationship of stents and surrounding rock and the situation of coal wall piece. Put forward the corresponding measures should be taken.(3) The article simulate coal seam by hydraulic cut seam when working face untapped, the stress changing rule around ordinary drilling along with working face advancing, the stress changing rule around hydraulic cut seam with working face advancing and the mining surrounding damaging by FLAC3D.(4) Through measuring gas drainage, observing stents pressure curve and surveying mining coal wall piece in 9804 working face of KaiYuan coal mine of YangMei group, and comparative analysis to numerical simulation, draws the result is consistent with numerical simulation results, the numerical simulation results reflect truly actual situation. |
