矩形断面巷道冲击地压机理研究
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摘要
基于顶板剪切梁模型研究矩形巷道冲击地压发生问题,得到矩形断面巷道发生冲击地压的临界塑性软化区深度和临界载荷,分析巷道宽度、巷道高度或煤层厚度、顶板厚度等几何因素,以及煤层与顶板刚度比、煤的模量比、煤的强度参数、侧压力系数和水平应力分布指数等煤岩力学性质因素对临界条件的影响规律。结果表明:巷道顶板岩层以剪切变形破坏为主,当临界塑性区深度与临界载荷较小时,易于发生冲击地压,其发生频度较高,强度较小,破坏性较小;反之,冲击地压不易发生,其发生频度较低,一旦发生其强度会较大,破坏性较大。临界塑性区深度与巷道宽高比、初始黏聚力的大小无关,随顶板厚度、刚度比、模量比、水平应力分布指数的增加而增大,随煤层塑性软化刚度、内摩擦角、侧压力系数的增加而减小。临界载荷随巷道宽高比、煤层塑性软化刚度、水平应力分布指数的增加而降低,随顶板厚度、刚度比、模量比、初始黏聚力、内摩擦角、侧压力系数的增加而增大。
The critical plastic softening zone depth and the critical load of rock bursts in a rectangular section tunnel are obtained based on the roof shear beam model for rock burst problem of roadway, and the effects of correlation factors on the critical conditions are investigated. The results show that the damage of roof rock strata is dominated by the shear deformation, and the critical depth and the critical load of the plastic zone are important parameters for identifying risk impact. Rock burst will easily happen if the critical depth and the critical load of the plastic zone are small. Its occurrence frequency is higher, but its intensity is smaller, and the destruction is also small. When they are large enough, the opposite situations occur. The influence factors of rectangular section in roadways include roadway width, height or thickness of coal seam, thickness of roof, stiffness ratio of coal seam and roof, modulus, intensity parameter, lateral pressure coefficient and horizontal stress distribution index. The critical depth of the plastic zone increases a little with the height-width ratio of roadway, and it increases with the increase of the thickness of the roof, stiffness ratio and horizontal stress distribution index. It decreases with the increasing plastic stiffness softening, internal friction angle and lateral pressure coefficient, and it has nothing to do with the initial magnitude of the cohesive force. The critical load decreases with the height-width ratio of roadway and it increases with the increase of the thickness of the roof, stiffness ratio, modulus ratio, cohesive force, internal friction angle and lateral pressure coefficient. It decreasess with the increasing plastic stiffness softening and horizontal stress distribution index.
The critical plastic softening zone depth and the critical load of rock bursts in a rectangular section tunnel are obtained based on the roof shear beam model for rock burst problem of roadway, and the effects of correlation factors on the critical conditions are investigated. The results show that the damage of roof rock strata is dominated by the shear deformation, and the critical depth and the critical load of the plastic zone are important parameters for identifying risk impact. Rock burst will easily happen if the critical depth and the critical load of the plastic zone are small. Its occurrence frequency is higher, but its intensity is smaller, and the destruction is also small. When they are large enough, the opposite situations occur. The influence factors of rectangular section in roadways include roadway width, height or thickness of coal seam, thickness of roof, stiffness ratio of coal seam and roof, modulus, intensity parameter, lateral pressure coefficient and horizontal stress distribution index. The critical depth of the plastic zone increases a little with the height-width ratio of roadway, and it increases with the increase of the thickness of the roof, stiffness ratio and horizontal stress distribution index. It decreases with the increasing plastic stiffness softening, internal friction angle and lateral pressure coefficient, and it has nothing to do with the initial magnitude of the cohesive force. The critical load decreases with the height-width ratio of roadway and it increases with the increase of the thickness of the roof, stiffness ratio, modulus ratio, cohesive force, internal friction angle and lateral pressure coefficient. It decreasess with the increasing plastic stiffness softening and horizontal stress distribution index.
引文
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[2]潘一山,章梦涛.冲击地压失稳理论的解析分析[J].岩石力学与工程学报,1996,15(增刊):504–510.(PAN Yi-shan,ZHANG Meng-tao.The exact solution for rockburst in coal mine by unstability rockburst theory[J].Chinese Journal of Rock Mechanics and Engineering,1996,15(S0):504–510.(in Chinese))
[3]潘一山.冲击地压发生和破坏过程研究[D].北京:清华大学,1999.(PAN Yi-shan.Study on rockburst initiation and failure propagation[D].Beijing:Tsinghua University,1999.(in Chinese))
[4]李忠华,官福海,潘一山.基于损伤理论的圆形巷道围岩应力场分析[J].岩土力学,2004,25(增刊):160–163.(LI Zhong-hua,GUAN Fu-hai,PAN Yi-shan.Analysis of stress field of rock surrounding circular roadway based on damage theory[J].Rock and Soil Mechanics,2004,25(S0):160–163.(in Chinese))
[5]魏悦广.两向不等压作用下圆形巷道弹塑性分析摄动解[J].岩土工程学报,1990,12(4):11–20.(WEI Yue-guang.Perturbation solutions for elasto-plastic analysis of cireular tunnel under unequal compression in two directions[J].Journal of Geotechnical Engineering,1990,12(4):11–20.(in Chinese))
[6]郭延华,姜福兴,张常光.高地应力下圆形巷道临界冲击地压解析解[J].工程力学,2011,28(2):118–122.(GUO Yan-hua,JIANG Fu-xing,ZHANG Chang-guang.Analytical solution for critical rockburst of a circular chamber subjected to high in-situ stress[J].Engineering Eechanics,2011,28(2):118–122.(in Chinese))
[7]黄庆享,高召宁.巷道冲击地压的损伤断裂力学模型[J].煤炭学报,2001,26(2):156–159.(HUANG Qing-xiang,GAO Zhao-ning.Mechanical model of fracture and damage of coal bump in the entry[J].Journal of China Coal Society,2001,26(2):156–159.(in Chinese))
[8]MENG Qing-bin,HAN Li-jun,QIAO Wei-guo,et al.Support technology for mine roadways in extreme weakly cemented strata and its application[J].International Journal of Mining Science and Technology,2014,24(2):157–164.(in Chinese)
[9]PIETRUSZCZAK S,MROZ Z.Numerical analysis of elastic-plastic compression of pillars accounting for material hardening and softening[J].International Journal of Rock Mechanics&Mining Sciences&Geomechanics Abstracts,1980,17(4):199–207.
[10]PIETRUSZCZAK S,MRóZ Z.Finite element analysis of deformation of strain-softening materials[J].International Journal for Numerical Methods in Engineering,1981,17(3):327–334.
[11]MRóZ Z,NAWROCKI P.Deformation and stability of an elasto-plastic softening pillar[J].Rock Mechanics and Rock Engineering,1989,22:69–108.
[12]潘一山,李国臻,章梦涛.回采巷道冲击地压危险指标的确定[J].矿山压力与顶板管理,1994(1):56–59.(PAN Yi-shan,LI Guo-zhen,ZHANG Meng-tao.Determination of the rock burst hazardous indices in mining working[J].Ground Pressure and Strata Control,1994(1):56–59.(in Chinese))