围压循环加卸载作用下含瓦斯煤样渗透特性试验研究  

Permeability characteristics of gas-bearing coal specimens under cyclic loading-unloading of confining pressure

作　　者：贾恒义 王凯[1,2] 王益博 孙绪坤 JIA Hengyi;WANG Kai;WANG Yibo;SUN Xukun(School of Emergency Management and Safety Engineering,China University of Mining and Technology (Beijing),Beijing 100083,China;Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources,China University of Mining and Technology (Beijing),Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)应急管理与安全工程学院,北京100083 [2]中国矿业大学(北京)共伴生能源精准开采北京市重点实验室,北京100083

出　　处：《煤炭学报》2020年第5期1710-1718,共9页Journal of China Coal Society

基　　金：国家重点研发计划资助项目(2016YFC0801402);国家自然科学基金资助项目(51874314,51974321)。

摘　　要：煤与瓦斯突出综合假说明确了地应力、瓦斯及煤的物理力学性质对突出发生所起的主体作用。对比研究采动影响下型煤煤样和原煤煤样的渗透率响应特征,对于揭示两种煤样微细观结构损伤演化规律的异同、明确型煤煤样能否代替原煤煤样开展相关试验研究具有重要意义。以原煤煤样和型煤煤样为研究对象,采用自主研发的三轴煤岩渗透率试验系统,进行围压等幅循环加卸载渗流试验,研究渗透率对应力的响应特征。结果表明,两种煤样渗透率对应力的响应特征总体相似,但存在细节差异。①对于2种煤样,渗透率随围压的增大而减小,随围压的减小而增大,且任一次加载过程的渗透率均大于该次卸载过程的渗透率。②原煤煤样的渗透率在低围压阶段变化程度大,在高围压阶段变化程度小,而型煤煤样的渗透率在整个加卸载过程中几乎呈均等变化。③原煤煤样和型煤煤样的渗透率损害率Dk均随加卸载循环次数的增加和瓦斯压力的增加逐渐减小。④原煤煤样和型煤煤样的裂隙压缩系数cf整体上随加卸载次数的增加而减小,随瓦斯压力的增加而增大。⑤原煤煤样的渗透率随瓦斯压力的增加而增大,型煤煤样的渗透率随瓦斯压力的增加而减小。用型煤煤样来代替原煤煤样研究含瓦斯煤的渗流特征是可行的,而且在某些特定场合还具有一定的优越性,但同时也应该注意两种煤样渗透率对应力响应特征的细节差异,以及这些细节差异给试验结果的可靠性所带来的影响。The comprehensive supposition of coal and gas outburst confirms the main role of stress,gas and the physical and mechanical properties of coal in the occurrence of coal and gas outburst.The comparative study of permeability response characteristics of reconstituted coal specimens and raw coal specimens under the influence of mining operation is of great significance to reveal the similarities and differences of micro structure damage evolution of the two coal specimens and to clarify whether the reconstituted coal specimens can replace the raw coal specimens for carrying out relevant experimental study.Some seepage experiments were conducted under a cyclic loading of confining pressure on raw coal specimens and reconstituted coal specimens to investigate the response characteristics of permeability to stress.The self-developed triaxial coal and rock permeability experimental system was used to carry out the test.The results show that the response characteristics of permeability to the stress of the two coal samples are similar in general,but there are differences in details.For both types of coal specimens,the permeability decreases with the increase of confining pressure and increases with the decrease of confining pressure.The permeability of any one loading process is greater than the permeability of unloading process.The permeability of the raw coal specimen changes greatly in low confining pressure stage and changes slowly in high confining pressure stage.The permeability of the reconstituted coal specimen changes uniformly throughout loading and unloading processes.The permeability damage rates of the raw coal specimen and the reconstituted coal specimen decrease with the increasing cyclic times of confining pressure and the increasing gas pressure.The fracture compression coefficients of the raw coal specimen and the reconstituted coal specimen decrease with the increase of cyclic times of confining pressure,and increase with the increase of gas pressure.The permeability of raw coal specimen increases with

关 键 词：含瓦斯煤 渗透率 循环加卸载 裂隙压缩系数 渗透率损害率 

分 类 号：TD324[矿业工程—矿井建设] TD712