煤与瓦斯突出过程中地应力、瓦斯压力作用机理探讨
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摘要
基于煤岩破裂损伤理论和气固耦合方法,针对不同地应力和不同瓦斯压力条件,采用RFPA2D-Flow数值计算软件对煤与瓦斯突出发生、发展过程进行数值研究,获得了煤体裂纹孕育、扩展演化规律及突出孔洞变化特征,并结合红阳二矿、西马煤矿突出实例进行验证分析。研究表明:地应力与煤与瓦斯突出发生所需的最小瓦斯压力呈线性反比关系,地应力越高突出所需的瓦斯压力越小;高地应力条件下煤与瓦斯突出的初始阶段,煤体主要在剪-拉应力作用下,形成以"–"型和"I"型裂纹组成的网格型裂纹,宏观破坏呈楔形分布,而较低地应力条件下煤与瓦斯突出的初始阶段,煤体主要在拉应力作用下,形成"I"型裂纹,宏观破坏呈环状分布;突出过程中地应力的作用使煤体破坏以楔形方式发展,瓦斯的作用使煤体破坏以弧形方式发展,突出孔洞的最终形状由地应力和瓦斯共同决定。
Based on the coal & rock failure damage theories analysis and gas-solid coupling method, the coal and gas outburst development processes under different gas pressures and ground stress conditions are simulated using the RFPA~(2D)-Flow software. The evolution of coal failure such as initial damage, crack propagation, shape of hole and other prominent damage features are obtained by numerical experiments and the results are validated by examples of outburst happened in Hongyang and Xima coal mine. The research shows that the limited gas pressure of outburst is inversely proportional to the ground stress, the greater the ground stress is, the smaller the gas pressure required for an outburst is. When the shapes of "–" micro cracks and "I" micro cracks engendered by shear-tensile stress form cross connection cracks, the distribution zone of macro fractures begins to emerge and form the shape of wedge damage area in the initialization phase of outburst under high ground stress conditions, damage area in the initialization phase of outburst under high ground stress conditions, while the "I" cracks are engendered by tensile stress, the distribution zone of macro fractures begin to emerge and form shape of hemispherical damage area under low ground stress and high gas pressure conditions. The shape of damage area and outburst hole extend towards wedge by the effect of ground stress while extend towards half arc shape by the effect of gas pressure. The final shape of outburst hole is the result of combined effects.
Based on the coal & rock failure damage theories analysis and gas-solid coupling method, the coal and gas outburst development processes under different gas pressures and ground stress conditions are simulated using the RFPA~(2D)-Flow software. The evolution of coal failure such as initial damage, crack propagation, shape of hole and other prominent damage features are obtained by numerical experiments and the results are validated by examples of outburst happened in Hongyang and Xima coal mine. The research shows that the limited gas pressure of outburst is inversely proportional to the ground stress, the greater the ground stress is, the smaller the gas pressure required for an outburst is. When the shapes of "–" micro cracks and "I" micro cracks engendered by shear-tensile stress form cross connection cracks, the distribution zone of macro fractures begins to emerge and form the shape of wedge damage area in the initialization phase of outburst under high ground stress conditions, damage area in the initialization phase of outburst under high ground stress conditions, while the "I" cracks are engendered by tensile stress, the distribution zone of macro fractures begin to emerge and form shape of hemispherical damage area under low ground stress and high gas pressure conditions. The shape of damage area and outburst hole extend towards wedge by the effect of ground stress while extend towards half arc shape by the effect of gas pressure. The final shape of outburst hole is the result of combined effects.
引文
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[16]赵卫华,孙东生,王红才,等.沈阳红菱煤矿地应力测量[J].地质力学学报,2008,14(3):286-290.ZHAO Weihua,SUN Dongsheng,WANG Hongcai,et al.Measurement of rock stress of Hongling coal mine[J].Journal of Geomechanics,2008,14(3):286-290.
[2]赵志刚,谭云亮,程国强.煤巷掘进迎头煤与瓦斯突出的突变机制分析[J].岩土力学,2008,29(6):1644-1648.ZHAO Zhigang,TAN Yunliang,CHENG Guoqiang.Catastrophe mechanism analysis of coal and gas outburst in coal heading face[J].Rock and Soil Mechanics,2008,29(6):1644-1648.
[3]潘岳,赵志刚,张孝武.煤岩突出中孔深扩展与孔洞形成的阵发混沌模型[J].岩土力学,2010,31(8):2604-2612.PAN Yue,ZHAO Zhigang,ZHANG Xiaowu.Intermittent chaotic model of hole depth developing and opening formation in coal and gas outburst[J].Rock and Soil Mechanics,2010,31(8):2604-2612.
[4]王恩义.煤与瓦斯突出机制研究[J].焦作工学院学报(自然科学版),2004,23(6):419-422.WANG Enyi.Study of the mechanism of coal and gas outbursts[J].Journal of Jiaozuo Institute of Technology(Natural Science),2004,23(6):419-422.
[5]李铁,梅婷婷,李国旗,等.“三软”煤层冲击地压诱导煤与瓦斯突出力学机制研究[J].岩石力学与工程学报,2011,30(6):1283-1288.LI Tie,MEI Tingting,LI Guoqi,et al.Mechanism study of coal and gas outburst induced by rockburst in“three-soft”coal seam[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(6):1283-1288.
[6]郑哲敏.从数量级和量纲分析看煤与瓦斯突出的机理[C]//郑哲敏文集.北京:科学出版社,2004:382-392.
[7]周世宁,何学秋.煤和瓦斯突出机理的流变假说[J].中国矿业大学学报,1990,19(2):1-8.ZHOU Shining,HE Xueqiu.Rheological hypothesis of coal and methane outburst mechanism[J].Journal of China University of Mining&Technology,1990,19(2):1-8.
[8]蒋承林,俞启香.煤与瓦斯突出机理的球壳失稳假说[J].煤矿安全,1995(2):17-25.JIANG Chenglin,YU Qixiang.The hypothesis of spherical shell destabilization of coal and gas outburst[J].Safety in Coal Mine,1995(2):17-25.
[9]梁冰,章梦涛,潘一山,等.煤和瓦斯突出固流耦合失稳理论[J].煤炭学报,1995,20(5):492-496.LIANG Bing,ZHANG Mengtao,PAN Yishan,et al.Theory of instability of flow fixation coupling for coal and gas outburst[J].Journal of China Coal Society,1995,20(5):492-496.
[10]蔡成功.煤与瓦斯突出三维模拟实验研究[J].煤炭学报,2004,29(1):66-69.CAI Chenggong.Experimental study on 3D simulation of coal and gas outbursts[J].Journal of China Coal Society,2004,29(1):66-69.
[11]胡千庭.煤与瓦斯突出的力学作用机理及应用研究[D].北京:中国矿业大学(北京),2007.
[12]徐涛,唐春安,宋力,等.含瓦斯煤岩破裂过程流固耦合数值模拟[J].岩石力学与工程学报,2005,24(10):1667-1673.XU Tao,TANG Chun’an,SONG Li,et al.Numerical simulation of coupled gas flow in failure process of gassy coal-rock[J].Chinese Journal of Rock Mechanics and Engineering,2005,24(10):1667-1673.
[13]欧建春.煤与瓦斯突出演化过程模拟实验研究[D].徐州:中国矿业大学,2012.
[14]段东,唐春安,李连崇,等.煤和瓦斯突出过程中地应力作用机理[J].东北大学学报(自然科学版),2009,30(9):1326-1329.DUAN Dong,TANG Chun’an,LI Lianchong,et al.Study on the mechanism of ground stress in coal-gas outburst[J].Journal of Northeastern University(Natural Science),2009,30(9):1326-1329.
[15]孙东生,王连捷,赵卫华,等.地应力测量在煤与瓦斯突出灾害研究中的应用[J].中国地质,2010,237(1):223-227.SUN Dongsheng,WANG Lianjie,ZHAO Weihua,et al.The application of in-situ stress measurement to the study of coal and gas outburst in coal mines[J].Geology in China,2010,237(1):223-227.
[16]赵卫华,孙东生,王红才,等.沈阳红菱煤矿地应力测量[J].地质力学学报,2008,14(3):286-290.ZHAO Weihua,SUN Dongsheng,WANG Hongcai,et al.Measurement of rock stress of Hongling coal mine[J].Journal of Geomechanics,2008,14(3):286-290.