吸附性气体对构造煤的损伤效应试验研究
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摘要
为揭示吸附性气体对煤的损伤作用机理,利用可视化恒定容积气固耦合试验装置分别开展了CO_2,CH_4,N_2,He 4种气体诱发型煤损伤试验研究,测定了不同吸附性气体作用下型煤单轴抗压强度和破坏形态,并用颗粒流软件PFC进行了数值模拟。主要结论如下:1)不具吸附性的He对煤的单轴抗压强度基本无影响;2)煤体强度损失与气体吸附量呈现一致性,相同吸附平衡压力下,气体吸附性越强,煤的损伤越显著,先后顺序为:CO_2> CH4>N2;3)煤的破坏形态和裂纹扩展规律与气体吸附量相关,CO_2作用下煤体裂纹呈现"裂隙窄、数量多"的特点,He作用下煤体裂纹呈现"裂隙宽、数量少"的特点;4)气体吸附诱导煤颗粒间的接触发生改变,煤粒吸附气体将引发颗粒间的黏结抗拉强度和黏结黏聚力减小,进而引起宏观力学参数变化,造成煤岩损伤和强度损失。
In order to reveal the damage mechanism of structural coal by adsorbent gas, the structural coal damage test induced by four gas of CO_2, CH_4, N_2 and He was carried out by visualized constant volume gas-solid coupling test device. The uniaxial compressive strength and failure mode of coal were measured by the test, and then simulated by particle flow software PFC. The main conclusions are as follows: 1) As He isn't adsorbent gas, it has no effect on the uniaxial compressive strength of coal; 2) The strength loss of coal is consistent with the amount of gas adsorption. Under the same adsorption equilibrium pressure, the degree of coal damage increases in accordance with the gas adsorption amount. The degree of coal damage is: CO_2> CH_4> N2; 3) The failure mode and crack propagation characteristics of coal are also related to the amount of gas adsorption. The coal damage under CO_2 is characterized by "narrow crack with large quantity". However, the coal damage under He shows the characteristics of "wide crack with small quantity"; 4) The gas absorption induces the change of contact between coal particles, and the tensile strength and the cohesive force of the bond between the particles are then reduced by those adsorbed gas, which could cause changes in macroscopic mechanical parameters, resulting in coal and rock damage and strength loss.
In order to reveal the damage mechanism of structural coal by adsorbent gas, the structural coal damage test induced by four gas of CO_2, CH_4, N_2 and He was carried out by visualized constant volume gas-solid coupling test device. The uniaxial compressive strength and failure mode of coal were measured by the test, and then simulated by particle flow software PFC. The main conclusions are as follows: 1) As He isn't adsorbent gas, it has no effect on the uniaxial compressive strength of coal; 2) The strength loss of coal is consistent with the amount of gas adsorption. Under the same adsorption equilibrium pressure, the degree of coal damage increases in accordance with the gas adsorption amount. The degree of coal damage is: CO_2> CH_4> N2; 3) The failure mode and crack propagation characteristics of coal are also related to the amount of gas adsorption. The coal damage under CO_2 is characterized by "narrow crack with large quantity". However, the coal damage under He shows the characteristics of "wide crack with small quantity"; 4) The gas absorption induces the change of contact between coal particles, and the tensile strength and the cohesive force of the bond between the particles are then reduced by those adsorbed gas, which could cause changes in macroscopic mechanical parameters, resulting in coal and rock damage and strength loss.
引文
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[9]刘力源，朱万成，魏晨慧，等．气体吸附诱发煤体强度劣化的力学模型与数值模拟[J]．岩土力学，2018,39(4):1-9.LIU Liyuan,ZHU Wancheng,WEI Chenhui,et al.Mechanical model and numerical analysis for gas adsorption-induced coal mechanical property alterations[J].Rock and Soil Mechanics,2018,39(4):1-9．
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[16]张庆贺，王汉鹏，李术才，等．煤与瓦斯突出物理模拟试验中甲烷相似气体的探索[J]．岩土力学，2017,38(2):479-486.ZHANG Qinghe,WANG Hanpeng,LI Shucai,et al.Exploration of similar gas like methane in physical simulation test of coal and gas outburst[J].Rock and Soil Mechanics,2017,38(2):479-486．
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[19]王汉鹏，张庆贺，袁亮，等．含瓦斯煤相似材料研制及其突出试验应用[J]．岩土力学，2015,36(6):1676-1682.WANG Hanpeng,ZHANG Qinghe,YUAN Liang,et al.Development of a similar material for methane-bearing coal and its application to outburst experiment[J].Rock and Soil Mechanics,2015,36(6):1676-1682．
[20]中华人民共和国国家质量监督检验检疫总局．GB/T19560-2008煤的高压等温吸附实验方法[S]．北京：[s.n.],2008．
[21]TENG T,WANG J G,GAO F,et al.Complex thermal coal-gas interactions in heat injection enhanced CBM recovery[J].Journal of Natural Gas Science and Engineering,2016,34:1174-1190.
[2]袁亮．煤及共伴生资源精准开采科学问题与对策[J]．煤炭学报，2019,44(1):1-9.YUAN Liang.Scientific problem and countermeasure for precision mining of coal and associated resources[J].Journal of China Coal Society,2019,44(1):1-9．
[3]梁卫国，张倍宁，黎力，等．注能(以CO2为例)改性驱替开采CH4理论与实验研究[J]．煤炭学报，2018,43(10):2839-2847.LIANG Weiguo,ZHANG Beining,LI Li,et al.Theory and experimental study of CBM recovery driven by energy boosting[J].Journal of China Coal Society,2018,43(10):2839-2847．
[4]封官宏．二氧化碳置换煤层气(CO2-ECBM)地质工程中多相渗流和相态转化过程分析与数值模型[D]．长春：吉林大学，2018．
[5]孙杰，王佟，赵欣，等．我国煤层气地质特征与研究方向思考[J]．中国煤炭地质，2018,30(6):30-34,40.SUN Jie,WANG Dong,ZHAO Xin,et al.Geological characteristics and research direction of CBM in China[J].Coal Geology of China,2018,30(6):30-34,40．
[6]WEI X,MASSAROTTO P,WANG G,et al.CO2sequestration in coals and enhanced coal bed methane recovery:new numerical approach[J].Fuel,2010,89(5):1110-1118．
[7]LI X,FANG Z.Current status and technical challenges of CO2 storage in coal seams and enhanced coalbed methane recovery:an overview[J].International Journal of Coal Science&Technology,2014,1(1):93-102．
[8]朱立．CO2地下封存煤/盖层变形和破裂演化特征研究[D]．徐州：中国矿业大学，2014．
[9]刘力源，朱万成，魏晨慧，等．气体吸附诱发煤体强度劣化的力学模型与数值模拟[J]．岩土力学，2018,39(4):1-9.LIU Liyuan,ZHU Wancheng,WEI Chenhui,et al.Mechanical model and numerical analysis for gas adsorption-induced coal mechanical property alterations[J].Rock and Soil Mechanics,2018,39(4):1-9．
[10]何学秋，王恩元，林海燕．孔隙气体对煤体变形及蚀损作用机理[J]．中国矿业大学学报，1996,25(1):6-11.HE Xueqiu,WANG Enyuan,LIN Haiyan.Mechanism of action of pore gas on deformation and erosion of coal body[J].Journal of China University of Mining&Technology,1996,25(1):6-11．
[11]KARACAN C O.Swelling-induced volumetric strains internal to a stressed coal associated with CO2 sorption[J].International Journal of Coal Geology,2007,72(3-4):209-220．
[12]RANJITH P G,JASINGE D,CHOI S K,et al.The effect of CO2 saturation on mechanical properties of Australian black coal using acoustic emission[J].Fuel,2010,89(8):2110-2117．
[13]VIETE D R,RANJITH P G.The effect of CO2 on the geomechanical and permeability behaviour of brown coal:implications for coal seam CO2 sequestration[J].International Journal of Coal Geology,2006,66(3):204-216．
[14]聂百胜，卢红奇，李祥春，等．煤体吸附-解吸瓦斯变形特征实验研究[J]．煤炭学报，2015,40(4):754-759.NIE Baisheng,LU Hongqi,LI Xiangchun,et al.Experimental study on the characteristic of coal deformation during gas adsorption and desorption process[J].Journal of China Coal Society,2015,40(4):754-759．
[15]梁冰，贾立锋，孙维吉，等．横观各向同性煤等温吸附变形试验研究[J]．中国矿业大学学报，2018,47(1):60-66.LIANG Bing,JIA Lifeng,SUN Weiji,et al.Experimental study of isothermal adsorption deformation of transversely isotropic coal[J].Journal of China University of Mining&Technology,2018,47(1):60-66．
[16]张庆贺，王汉鹏，李术才，等．煤与瓦斯突出物理模拟试验中甲烷相似气体的探索[J]．岩土力学，2017,38(2):479-486.ZHANG Qinghe,WANG Hanpeng,LI Shucai,et al.Exploration of similar gas like methane in physical simulation test of coal and gas outburst[J].Rock and Soil Mechanics,2017,38(2):479-486．
[17]滕腾，高峰，高亚楠，等．循环气压下原煤微损伤及其破碎特性试验研究[J]．中国矿业大学学报，2017,46(2):306-311.TENG teng,GAO Feng,GAO Yanan,et al.Experimental study of micro-damage and fracturing characteristics on raw coal under cyclic pneumatic hydraulic loading[J].Journal of China University of Mining&Technology,2017,46(2):306-311．
[18]李清川，王汉鹏，李术才，等．可视化恒容气固耦合试验系统的研发与应用[J]．中国矿业大学学报，2018,47(1):148-156.LI Qingchuan,WANG Hanpeng,LI Shucai,et al.Development and application of a gas-solid coupling test system in the visual and constant volume loading state[J].Journal of China University of Mining&Technology,2018,47(1):148-156．
[19]王汉鹏，张庆贺，袁亮，等．含瓦斯煤相似材料研制及其突出试验应用[J]．岩土力学，2015,36(6):1676-1682.WANG Hanpeng,ZHANG Qinghe,YUAN Liang,et al.Development of a similar material for methane-bearing coal and its application to outburst experiment[J].Rock and Soil Mechanics,2015,36(6):1676-1682．
[20]中华人民共和国国家质量监督检验检疫总局．GB/T19560-2008煤的高压等温吸附实验方法[S]．北京：[s.n.],2008．
[21]TENG T,WANG J G,GAO F,et al.Complex thermal coal-gas interactions in heat injection enhanced CBM recovery[J].Journal of Natural Gas Science and Engineering,2016,34:1174-1190.