液氮冻融对不同含水率煤岩力学与渗流特性影响研究  

Study on Mechanical and Seepage Characteristics of Liquid Nitrogen Freeze⁃Thaw Coal with Different Water Content

作　　者：齐消寒 张颖 侯双荣[3] 刘晓东 刘忠桦 谢文坤[1,2] QI Xiaohan;ZHANG Ying;HOU Shuangrong;LIU Xiaodong;LIU Zhonghua;XIE Wenkun(School of Safety Science and Engineering,Liaoning Technical University,Huludao 125105,Liaoning,China;Key Laboratory of Mine Thermodynamic Disasters and Control of Education(Liaoning University),Huludao 125105,Liaoning,China;Xukuang Group Tianshan Mining Company,Kuche 842008,Xinjiang,China)

机构地区：[1]辽宁工程技术大学安全科学与工程学院,辽宁葫芦岛125105 [2]矿山热动力灾害与防治教育部重点实验室(辽宁工程技术大学),辽宁葫芦岛125105 [3]徐矿集团天山矿业公司,新疆库车842008

出　　处：《力学季刊》2024年第3期808-824,共17页Chinese Quarterly of Mechanics

基　　金：国家自然科学基金(52274205);教育部重点实验室开放基金(JSK202010)。

摘　　要：为探究液氮冻融对不同含水率煤岩力学渗流特性的影响规律,采用非接触式数字图像技术测量流固耦合试验系统,进行不同含水率下冻融煤岩三轴加载及渗流实验研究.研究结果表明:(1)经液氮冻融2次处理的煤岩,在围压相同轴压加载试验中,随含水率增加,煤体细观损伤增强,轴向峰值应变、峰值强度和弹性模量逐渐降低,泊松比逐渐增加.(2)液氮冻融下不同含水率的煤样在压密、弹性、屈服和破坏4阶段的轴向应变场中应变集中现象强烈,在压密、弹性和屈服阶段应变场存在负值,媒体产生膨胀变形.(3)液氮冻融引起的裂隙扩展增加了煤体的渗透性,含水率3%~6%煤样较含水率0%~3%渗透率增长1.31倍,含水率6%~9%煤样渗透率较3%~6%煤样增长1.43倍,含水率9%煤样渗透率可达9.37×10^(-12)cm^(2).本文研究结果可为深部低渗煤层瓦斯抽采效率提供理论指导.In order to explore the effect of liquid nitrogen freeze-thaw on mechanical seepage characteristics of coal and rock with different water content,a non-contact digital image measurement fluid-structure coupling test system was used to carry out experimental research on the triaxial loading and seepage of freeze-thaw coal and rock with different water content.The results show that:(1)In the coaxial-compression loading test of the confining pressure phase,with the increase of water content,the microscopic damage of coal is enhanced,the axial peak strain,peak strength and elastic modulus gradually decrease,and Poisson's ratio gradually increases.(2)The axial strain concentration of coal samples with different moisture content under liquid nitrogen freeze-thaw is strong in the four stages,i.e.,compaction,elasticity,yield and failure,and there is negative strain in the strain field in the compaction,elasticity and yield stages,resulting in expansion deformation of coal.(3)The crack expansion caused by liquid nitrogen freeze-thaw increases the permeability of the coal body,and the permeability of coal sample with moisture content of 3%‒6%increases by 1.31 times compared with that with moisture content of 0%‒3%.The permeability of coal sample with moisture content of 6%‒9%increases by 1.43 times compared with that with 3%‒6%.The permeability of coal sample with moisture content of 9%can reach 9.37×10^(-12)cm^(2).The research results can provide theoretical guidance for the efficiency of gas extraction in deep low-permeability coal seams.

关 键 词：非接触式数字图像处理 三轴加载 含水率 液氮冻融 渗透率 

分 类 号：X9[环境科学与工程—安全科学]