分段变速加载对含瓦斯突出煤力学特性影响试验研究
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摘要
为探究采动应力变化对含瓦斯突出煤力学特性的影响,利用RLW-500G煤岩三轴蠕变-渗流试验系统,对新景矿含瓦斯突出煤进行了不同围压和瓦斯压力下的常规三轴和分段变速加载力学试验。结果表明:煤样在2种应力路径下的全应力应变曲线均可分为压密、线弹性、塑性变形、应力跌落和残余应力5个阶段;随着围压的升高或者瓦斯压力的降低,煤体在2种应力路径下的强度和弹性模量均增大;相较于常规三轴,煤体在分段变速加载路径下的强度普遍增大,峰值轴向应变、峰值环向应变绝对值和峰值体积应变绝对值也普遍增大,失稳破坏瞬间应力跌落和能量释放更加剧烈。Mohr-Coulomb强度准则仍然适用于分段变速加载条件下的含瓦斯突出煤,该研究对于认识煤与瓦斯突出的发生机制具有一定的指导意义。
In order to explore the influence of the changing mining stress on the mechanical properties of outburst coal containing gas,the mechanical tests of conventional triaxial loading and piecewise variable speed loading on the outburst coal containing gas in Xinjing mine under different confining pressures and gas pressures were carried out by using RLW-500 G coal and rock triaxial creepage-seepage test system. The results showed that the total stress-strain curves of coal samples under two stress paths could be divided into 5 stages: compaction,linear elasticity,plastic deformation,stress drop and residual stress. With the increase of confining pressure or the decrease of gas pressure,both the strength and elastic modulus of the coal body increased under two stress paths. Compared with the conventional triaxial loading,the strength of coal body under the path of piecewise variable speed loading increased generally,the peak axial strain,absolute value of peak circumferential strain and absolute value of peak volume strain also increased generally,and the stress drop and energy release were more drastic on the moment of instability failure. The Mohr-Coulomb strength criterion was still applicable to the outburst coal containing gas under the conditions of piecewise variable speed loading. The study has a certain guiding significance for understanding the occurrence mechanism of coal and gas outburst.
In order to explore the influence of the changing mining stress on the mechanical properties of outburst coal containing gas,the mechanical tests of conventional triaxial loading and piecewise variable speed loading on the outburst coal containing gas in Xinjing mine under different confining pressures and gas pressures were carried out by using RLW-500 G coal and rock triaxial creepage-seepage test system. The results showed that the total stress-strain curves of coal samples under two stress paths could be divided into 5 stages: compaction,linear elasticity,plastic deformation,stress drop and residual stress. With the increase of confining pressure or the decrease of gas pressure,both the strength and elastic modulus of the coal body increased under two stress paths. Compared with the conventional triaxial loading,the strength of coal body under the path of piecewise variable speed loading increased generally,the peak axial strain,absolute value of peak circumferential strain and absolute value of peak volume strain also increased generally,and the stress drop and energy release were more drastic on the moment of instability failure. The Mohr-Coulomb strength criterion was still applicable to the outburst coal containing gas under the conditions of piecewise variable speed loading. The study has a certain guiding significance for understanding the occurrence mechanism of coal and gas outburst.
引文
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[2]赵洪宝,李振华,仲淑姮,等.单轴压缩状态下含瓦斯煤岩力学特性试验研究[J].采矿与安全工程学报,2010,27(1):131-134.ZHAO Hongbao,LI Zhenhua,ZHONG Shuheng,et al.Experimental study of mechanical properties of coal rock containing gas under uniaxial compression[J].Journal of Mining&Safe ty Engineering,2010,27(1):131-134.
[3]李海涛,蒋春祥,姜耀东,等.加载速率对煤样力学行为影响的试验研究[J].中国矿业大学学报,2015,44(3):430-436.LI Haitao,JIANG Chunxiang,JIANG Yaodong,et al.Experimental study on the effect of loading rate on mechanical behavior of coal samples[J].Journal of China University of Mining and Technology,2015,44(3):430-436.
[4]尹小涛,葛修润,李春光,等.加载速率对岩石材料力学行为的影响[J].岩石力学与工程学报,2010,29(S1):2610-2615.YIN Xiaotao,GE Xiurun,LI Chunguang,et al.Influences of loading rates on mechanical behaviors of rock materials[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(S1):2610-2615.
[5]刘恺德.高应力下含瓦斯原煤三轴压缩力学特性研究[J].岩石力学与工程学报,2017,36(2):380-392.LIU Kaide.Mechanical properties of ram coal containing gas under high triaxal stress compression[J].Chinese Journal of Rock Mechanics and Engineering,2017,36(2):380-392.
[6]刘泉声,刘恺德,朱杰兵,等.高应力下原煤三轴压缩力学特性研究[J].岩石力学与工程学报,2014,33(1):24-33.LIU Quansheng,LIU Kaide,ZHU Jiebing,etal.Study of mechanical properties of raw coal under high stress with triaxial compression[J].Chinese Journal of Rock Mechanics and Engineering,2014,33(1):24-33.
[7]尹光志,李文璞,李铭辉,等.不同加卸载条件下含瓦斯煤力学特性试验研究[J].岩石力学与工程学报,2013,32(5):891-901.YIN Guangzhi,LI Wenpu,LI Minghui,et al.Experimental study of mechanical properties of coal containing methane under different loading-unloading conditions[J].Chinese Journal of Rock Mechanics and Engineering,2013,32(5):891-901.
[8]许江,李波波,周婷,等.加卸载条件下煤岩变形特性与渗透特征的试验研究[J].煤炭学报,2012,37(9):1493-1498.XU Jiang,LI Bobo,ZHOU Ting,et al.Experimental study of coal deformation and permeability characteristics under loading-unloading conditions[J].Journal of China Coal Society,2012,37(9):1493-1498.
[9]尹光志,李文璞,李铭辉,等.加卸载条件下原煤渗透率与有效应力的规律[J].煤炭学报,2014,39(8):1497-1503.YIN Guangzhi,LI Wenpu,LI Minghui,et al.Permeability properties and effective stress of roal coal under loading-unloading conditions[J].Journal of China Coal Society,2014,39(8):1497-1503.
[10]薛东杰,周宏伟,王子辉,等.不同加载速率下煤岩采动力学响应及破坏机制[J].煤炭学报,2016,41(3):595-602.XUE Dongjie,ZHOU Hongwei,WANG Zihui,et al.Failure mechanism and mining-induced mechanical properties of coal under different loading rates[J].Journal of China Coal Society,2016,41(3):595-602.
[11]马海峰,李传明,李家卓,等.不同推进速度下煤岩体采动力学行为响应特征与控制[J].中国安全生产科学技术,2016,12(12):74-79.MA Haifeng,LI Chuanming,LI Jiazhuo,et al.Response characteristics of mining-induced mechanical behavior for coal and rock mass under different advancing speedand itscontrol[J].Journal of Safety Science and Technology,2016,12(12):74-79.
[12]WANG K,FENG D,ZHANG X,et al.Mechanical properties and permeability evolution in gas-bearing coal-rock combination body under triaxial conditions[J].Environmental Earth Sciences,2017,76(24):815.
[13]VIETE D R,RANJITH P G.The mechanical behaviour of coal with respect to CO2sequestration in deep coal seams[J].Fuel,2007,44(4):387-394
[14]MAJEWSKA Z,MAJEWSKI S,ZIE TEK J.Swelling of coal induced by cyclic sorption/desorption of gas:experimental observations indicating changes in coal structure due to sorption of CO2and CH4Int.[J].Coal Geol,2010(83):475-483.
[15]WANG K,DU F.The influence of methane and CO2adsorption on the functional groups of coals:Insights from a Fourier transform infrared investigation[J].Journal of Natural Gas Science&Engineering,2017(34):811-822.
[16]闫露.煤岩体的强度准则研究[D].重庆:重庆大学,2014.
[17]谢文强.高压注水快速消突技术的应用与研究[J].能源技术与管理,2013,38(1):45-47.XIE Wenqiang.Application and research of high pressure water injection to eliminate outburst danger quickly[J].Energy Technology and Management,2013,38(1):45-47.