Abstract:Study on permeability distribution of coalface is of guiding significance in reasonable exploitation of gas. An equivalent mechanical model is established by simplifying the characteristics of pores and cracks. From the establishment of the equivalent mechanical model for a standard cylindrical coal-rock specimen, the equivalent formulas for axial, radial and volumetric strains are derived for coal-rock samples containing a single crack, and then are extended to the application in a variety of media combinations containing multiple cracks. The theoretical mechanical model shows good reliability by experimental verification. Based on the prototype of 11-2 coal seam mining face of Zhangji Mine in Huainan, the peak concentration factors of abutment pressure under three typical mining layouts are obtained by numerical calculation. An expression for the distribution of abutment pressure and horizontal stress is derived considering different mining layouts, different stages and volume expansion induced by mining. By establishing a polynomial relationship between volumetric strain and permeability, the distribution of volumetric strain and permeability under different mining layouts is obtained, and divided into different stages according to their various characteristics. It may provide a theoretical basis for the coal mine methane.
[1] 袁 亮. 卸压开采抽采瓦斯理论及煤与瓦斯共采技术体系[J]. 煤炭学报, 2011,36(7):1067-1074. (YUAN Liang. Theory of pressure-relieved gas extraction and technique system of integrated coal production and gas extraction[J]. Journal of China Coal Society, 2011, 36(7) [2] 李晓泉,尹光志. 含瓦斯煤的有效体积应力与渗透率关系[J]. 重庆大学学报, 2011,34(8):103-109. (LI Xiao-quan, YIN Guang-zhi. Relationship between effective volumetric stress and permeability of gas-filled coal[J]. Journal of Chongqing University, 2011, 34(8): 103-109. (in Chinese)) [3] 尹光志,蒋长宝,王维忠,等. 不同卸围压速度对含瓦斯煤岩力学和瓦斯渗流特性影响试验研究[J]. 岩石力学与工程学报, 2011,30(1):68-77. (YIN Guang-zhi, JIANG Chang-bao, WANG Wei-zhong, et al. Experimental study of influence of confining pressure unloading speed on mechanical properties and gas permeability of containing-gas coal rock[J]. Chinese Journal of Rock Mechanics and Engineering, 2011, 30(1) [4] 陈忠辉,谢和平. 综放采场支承压力分布的损伤力学分析[J]. 岩石力学与工程学报, 2000,19(4):436-439. (CHEN Zhong-hui, XIE He-ping. Damage mechanics analysis on the distribution of abutment pressure around a coal face[J]. Chinese Journal of Rock Mechanics and Engineering, 2000, 19(4): 436-439. (in Chinese)) [5] 王同旭,刘传孝,王小平. 孤岛煤柱侧向支承压力分布的数值模拟与雷达探测研究[J]. 岩石力学与工程学报, 2002,21(增刊2):2484-2487. (WANG Tong-xu, LIU Chuan-xiao, WANG Xiao-ping. FLAC3D numerical simulation and radar detection of lateral abutment pressure distribution of isolated coal pillar[J]. Chinese Journal of Rock Mechanics and Engineering, 2002, 21(S2): 2484-2487. (in Chinese)) [6] 浦 海,缪协兴. 综放采场覆岩冒落与围岩支承压力动态分布规律的数值模拟[J]. 岩石力学与工程学报, 2004,23(7):1122-1126. (PU Hai, MIAO Xie-xing. Numerical simulation of dynamic falling of overlying rocks and abutment pressure in surrounding rocks for fully-mechanized top-coal caving stope[J]. Chinese Journal of Rock Mechanics and Engineering, 2004, 23(7): 1122-1126. (in Chinese)) [7] 李树刚,林海飞,成连华. 综放开采支承压力与卸压瓦斯运移关系研究[J]. 岩石力学与工程学报, 2004,23(19):3288-3291. (LI Shu-gang, LIN Hai-fei, CHENG Lian-hua. Relation between abutment pressure and relieved gas delivery for fully-mechanized top coal caving[J]. Chinese Journal of Rock Mechanics and Engineering, 2004, 23(19): 3288-3291. (in Chinese)) [8] 谢广祥,杨 科,刘全明. 综放面倾向煤柱支承压力分布规律研究[J]. 岩石力学与工程学报, 2006,25(3):545-549. (XIE Guang-xiang, YANG Ke, LIU Quan-ming. Study on distribution laws of stress in inclined coal pillar for fully-mechanized top-coal caving face[J]. Chinese Journal of Rock Mechanics and Engineering, 2006, 25(3): 545-549. (in Chinese)) [9] 史 红,姜福兴. 基于微地震监测的覆岩多层空间结构倾向支承压力研究[J]. 岩石力学与工程学报, 2008,27(增刊1):3274-3280. (SNI Hong, JIANG Fu-xing. Study on abutment pressure rule of overlying strata spatial structures based on micro-seismic monitoring[J]. Chinese Journal of Rock Mechanics and Engineering, 2008, 27(S1): 3274-3280. (in Chinese)) [10] 刘金海,姜福兴,王乃国,等 深井特厚煤层综放工作面支承压力分布特征的实测研究[J]. 煤炭学报, 2011, 36(增刊1): 18-22. (LIU Jin-hai, JIANG Fu-xing,WANG Nai-guo, et al. Survey on abutment pressure distribution of fully -mechanized caving face in extra-thick coal seam of deep shaft[J]. Journal of China Coal Society, 2011, 36(S1):18-22. (in Chinese)) [11] 王龙甫. 弹性理论[M]. 北京: 科学出版社, 1979.(WANG Long-fu. Theory of elasticity[M]. Beijing: Science Press, 2002. (in Chinese)) [12] 李同林,乌效鸣,屠厚泽. 煤岩力学性质测试分析与应用[J]. 地质与勘探, 2000,36(2):85-88. (LI Tong-lin, WU Xiao-ming, TU Hou-ze. The measurement and analysis and application on the mechanical property of coal seam[J]. Geology and Prospecting, 2000, 36(2): 85-88. (in Chinese)) [13] 谢和平,周宏伟,刘建峰,等. 不同开采条件下采动力学行为研究[J]. 煤炭学报, 2011,36(7):1067-1074. (XIE He-ping, ZHOU Hong-wei, LIU Jian-feng, et al. Mining- induced mechanical behavior in coal seams under different mining layouts[J]. Journal of China Coal Society, 2011, 36(7)