循环加卸载作用下预制裂隙煤样渗透性试验研究
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摘要
应用三轴加载煤岩渗流试验装置,对预制贯通裂隙煤样开展循环加卸载轴压渗透率试验,分析循环加卸载轴压作用下预制裂隙煤样渗透率的变化规律及其之间的差异。研究结果表明:预制裂隙煤样渗透率与轴压呈负指数函数关系,渗透率对应力敏感性随加卸载次数增加而降低。加载阶段渗透率差值与卸载阶段渗透率差值随加卸载次数增加而降低,渗透率差值与应力敏感性系数呈正相关性。加载阶段与卸载阶段渗透率存在明显差值,渗透率产生明显损失量,其随加卸载次数增加而降低。竖直裂隙煤样渗透率与应力敏感性系数明显高于水平裂隙煤样与完整煤样,水平裂隙煤样渗透性与完整煤样渗透性相差不大,但水平裂隙煤样应力敏感性系数高于完整煤样。竖直裂隙煤样渗透率差值与渗透率损失量明显高于水平裂隙煤样与完整煤样,水平裂隙煤样渗透率差值高于完整煤样,但两者渗透率损失量相差不大。循环加卸载轴压结束后,完整煤样渗透率损失率最大,水平裂隙煤样渗透率损失率居中,竖直裂隙煤样渗透率损失率最小;竖直裂隙煤样渗透率恢复率最大,水平裂隙煤样渗透率恢复率居中,完整煤样渗透率恢复率最小。
The cyclic loading and unloading axial compression tests of coal specimens with the pre-existing transfixion fissure were carried out by triaxial loading coal rock seepage testing device. The permeability variation of coal specimen with pre-existing fissure and the difference with permeability of intact coal specimen were analyzed. The results show that the relationship between permeability and axial compression is a negative exponential function and the stress sensitivity of permeability decreases with the increase of the loading and unloading numbers for coal with pre-existing fissure. The permeability difference of the loading stage and permeability difference of unloading stage decrease with the increase of the loading and unloading numbers. There is a positive correlation between permeability difference and stress sensitivity coefficient. There exists a significant permeability difference during the loading and unloading stage, which indicates that there is apparent loss in permeability and it decreases with the increase of the loading and unloading numbers. The permeability and stress sensitivity coefficient of coal specimens with vertical fissure are higher than those of the coal specimens with horizontal fissure and the intact coal specimens. The permeability of coal specimen with horizontal fissure is similar to that of the intact coal specimen, but the stress sensitivity coefficient is higher than that of the intact coal specimen. The permeability difference and the loss quantity of permeability of coal specimens with vertical fissure are higher than those of the coal specimens with horizontal fissure and intact coal specimens. The permeability difference of coal specimens with horizontal fissure is higher than that of the intact coal specimens, but there is slight difference in the loss quantity of permeability between them. After the cyclic loading and unloading axial compression, the loss rate of permeability is the largest for intact coal specimen, followed by the coal specimen with horizontal fissure and last is the coal specimen with vertical fissure. The recovery rate of permeability is the largest for the coal specimen with vertical fissure, followed by the coal sample with horizontal fissure, and last is the intact coal sample.
The cyclic loading and unloading axial compression tests of coal specimens with the pre-existing transfixion fissure were carried out by triaxial loading coal rock seepage testing device. The permeability variation of coal specimen with pre-existing fissure and the difference with permeability of intact coal specimen were analyzed. The results show that the relationship between permeability and axial compression is a negative exponential function and the stress sensitivity of permeability decreases with the increase of the loading and unloading numbers for coal with pre-existing fissure. The permeability difference of the loading stage and permeability difference of unloading stage decrease with the increase of the loading and unloading numbers. There is a positive correlation between permeability difference and stress sensitivity coefficient. There exists a significant permeability difference during the loading and unloading stage, which indicates that there is apparent loss in permeability and it decreases with the increase of the loading and unloading numbers. The permeability and stress sensitivity coefficient of coal specimens with vertical fissure are higher than those of the coal specimens with horizontal fissure and the intact coal specimens. The permeability of coal specimen with horizontal fissure is similar to that of the intact coal specimen, but the stress sensitivity coefficient is higher than that of the intact coal specimen. The permeability difference and the loss quantity of permeability of coal specimens with vertical fissure are higher than those of the coal specimens with horizontal fissure and intact coal specimens. The permeability difference of coal specimens with horizontal fissure is higher than that of the intact coal specimens, but there is slight difference in the loss quantity of permeability between them. After the cyclic loading and unloading axial compression, the loss rate of permeability is the largest for intact coal specimen, followed by the coal specimen with horizontal fissure and last is the coal specimen with vertical fissure. The recovery rate of permeability is the largest for the coal specimen with vertical fissure, followed by the coal sample with horizontal fissure, and last is the intact coal sample.
引文
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[14]孙国文,罗甲渊,罗斌玉.煤层层理对瓦斯渗流影响理论分析与实验研究[J].湖南科技大学学报(自然科学版),2017,32(1):12-17.SUN Guo-wen,LUO Jia-yuan,LUO Bin-yu.Theory analysis and experimental study of the effect of coal seam on gas seepage[J].Journal of Hunan University of Science&Technology(Natural Science Edition),2017,32(1):12-17.
[15]亓宪寅,王威.基于结构异性比的含瓦斯煤渗透各向异性研究[J].岩土工程学报,2017,39(6):1030-1037.QI Xian-yin,WANG Wei.Anisotropic permeability model for coal containing methane based on anisotropic structure ratio[J].Chinese Journal of Geotechnical Engineering,2017,39(6):1030-1037.
[16]张村,屠世浩,张磊.覆岩不同采动损伤煤样应力敏感性研究[J].中国矿业大学学报,2018,47(3):502-511.ZHANG Cun,TU Shi-hao,ZHANG Lei.Study of stress sensitivity of coal samples with different mining damage in overlying strata[J].Journal of China University of Mining&Technology,2018,47(3):502-511.
[17]中华人民共和国行业标准编写组.GB/T23561.7-2009煤与岩石物理力学性质测定方法[S].北京:中国标准出版社,2009.The Professional Standard Compilation Group of People’s Republic of China.GB/T23561.7-2009 Methods for determining the physical and mechanical properties of coal and rock[S].Beijing:Standards Press of China,2009.
[2]涂敏,付宝杰.低渗透性煤层卸压瓦斯抽采机理研究[J].采矿与安全工程学报,2009,26(4):433-436.TU Min,FU Bao-jie.Extraction mechanism of relieved gas from low permeability seam[J].Journal of Mining&Safety Engineering,2009,26(4):433-436.
[3]陈金刚,秦勇,宋全友,等.割理方向与煤层气抽放效果的关系预测模型[J].中国矿业大学学报,2003,32(3):223-226.CHEN Jin-gang,QIN Yong,SONG Quan-you,et al.Coupling relationship between direction of coalbed cleat and methane drainage effect and its prediction model[J].Journal of China University of Mining&Technology,2003,32(3):223-226.
[4]LI H Y,SHIMADA S,ZHANG M.Anisotropy of gas permeability associated with cleat pattern in a coal seam of the Kushiro coalfield in Japan[J].Environmental Geology,2004,47(1):45-52.
[5]WANG S G,ELSWORTH D,LIU J S.Permeability evolution in fractured coal:the roles of fracture geometry and water-content[J].International Journal of Coal Geology,2011,87(1):13-25.
[6]黄雪满.煤结构异性对瓦斯渗透特性影响的实验研究[J].矿业安全与环保,2012,39(2):1-3.HUANG Xue-man.Experimental study on influence of structural anisotropy of coal upon gas permeability[J].Mining Safety&Environmental Protection,2012,39(2):1-3.
[7]潘荣锟,程远平,董骏,等.不同加卸载下层理裂隙煤体的渗透特性研究[J].煤炭学报,2014,39(3):473-477.PAN Rong-kun,CHENG Yuan-ping,DONG Jun,et al.Research on permeability characteristics of layered natural coal under different loading and unloading[J].Journal of China Coal Society,2014,39(3):473-477.
[8]栗东平,周宏伟,薛东杰,等.煤岩体采动裂隙网络的逾渗与分形特征关系研究[J].岩土力学,2015,36(4):1135-1140.LI Dong-ping,ZHOU Hong-wei,XUE Dong-jie,et al.Relationship between percolation and fractal properties of mining-induced crack network in coal and rock masses[J].Rock and Soil Mechanics,2015,36(4):1135-1140.
[9]张东明,齐消寒,宋润权,等.采动裂隙煤岩体应力与瓦斯流动的耦合机理[J].煤炭学报,2015,40(4):774-780.ZHANG Dong-ming,QI Xiao-han,SONG Run-quan,et al.Coupling mechanism of rock mass stress and gas flow in coal mining fissures[J].Journal of China Coal Society,2015,40(4):774-780.
[10]邓博知,康向涛,李星,等.不同层理方向对原煤变形及渗流特性的影响[J].煤炭学报,2015,40(4):888-894.DENG Bo-zhi,KANG Xiang-tao,LI Xing,et al.Effect of different bedding directions on coal deformation and permeability characteristics[J].Journal of China Coal Society,2015,40(4):888-894.
[11]康向涛,尹光志,黄滚,等.低透气性原煤瓦斯渗流各向异性试验研究[J].工程科学学报,2015,37(8):971-975.KANG Xiang-tao,YIN Guang-zhi,HUANG Gun,et al.Experimental research on gas seepage anisotropy in low-permeability coal[J].Chinese Journal of Engineering,2015,37(8):971-975.
[12]岳高伟,王辉,赵宇,等.结构异性煤体渗透率特性[J].科技导报,2015,33(2):50-55.YUE Gao-wei,WANG Hui,ZHAO Yu,et al.Permeability characteristics of structurally anisotropic coal[J].Science&Technology Review,2015,33(2):50-55.
[13]田坤云,齐雷.应力加卸载下层理裂隙煤体瓦斯渗流试验研究[J].中国安全科学学报,2017,27(1):93-97.TIAN Kun-yun,QI Lei.Experimental study on seepage of gas from fractured coal under stress loading and unloading conditions[J].China Safety Science Journal,2017,27(1):93-97.
[14]孙国文,罗甲渊,罗斌玉.煤层层理对瓦斯渗流影响理论分析与实验研究[J].湖南科技大学学报(自然科学版),2017,32(1):12-17.SUN Guo-wen,LUO Jia-yuan,LUO Bin-yu.Theory analysis and experimental study of the effect of coal seam on gas seepage[J].Journal of Hunan University of Science&Technology(Natural Science Edition),2017,32(1):12-17.
[15]亓宪寅,王威.基于结构异性比的含瓦斯煤渗透各向异性研究[J].岩土工程学报,2017,39(6):1030-1037.QI Xian-yin,WANG Wei.Anisotropic permeability model for coal containing methane based on anisotropic structure ratio[J].Chinese Journal of Geotechnical Engineering,2017,39(6):1030-1037.
[16]张村,屠世浩,张磊.覆岩不同采动损伤煤样应力敏感性研究[J].中国矿业大学学报,2018,47(3):502-511.ZHANG Cun,TU Shi-hao,ZHANG Lei.Study of stress sensitivity of coal samples with different mining damage in overlying strata[J].Journal of China University of Mining&Technology,2018,47(3):502-511.
[17]中华人民共和国行业标准编写组.GB/T23561.7-2009煤与岩石物理力学性质测定方法[S].北京:中国标准出版社,2009.The Professional Standard Compilation Group of People’s Republic of China.GB/T23561.7-2009 Methods for determining the physical and mechanical properties of coal and rock[S].Beijing:Standards Press of China,2009.