不同应力状态下底板岩体渗流特性分析研究  

Analysis and study on seepage characteristics of floor rock mass under different stress states

作　　者：张培森[1,2] 侯季群 赵成业 李腾辉 ZHANG Peisen;HOU Jiqun;ZHAO Chengye;LI Tenghui(National Key Laboratory for Mine Disaster Prevention and Control,Shandong University of Science and Technology,Qingdao266590,China;National Experimental Teaching Demonstration Center for Mining Engineering,Shandong University of Science and Technology,Qingdao 266590,China)

机构地区：[1]山东科技大学矿山灾害预防控制国家重点实验室培育基地,山东青岛266590 [2]山东科技大学矿业工程国家级实验教学示范中心,山东青岛266590

出　　处：《煤炭科学技术》2022年第1期127-133,共7页Coal Science and Technology

基　　金：国家重点研发计划资助项目(2018YFC0604702);国家自然科学基金资助项目(51379119);山东省自然科学基金资助项目(ZR2021ME086)。

摘　　要：为研究煤层开采过程中底板渗透性变化规律,利用Rock Top多场耦合试验仪,采用稳态和瞬态2种方法测得不同应力作用下红砂岩渗透率,对红砂岩加载过程中内部裂纹发展变化规律及渗流特性进行分析,结果表明:对岩样进行应力差20 MPa等梯度加载,全应力-应变曲线呈台阶状,根据裂纹体积应变法确定应力-应变各阶段的应变阈值,可将其划分为5个阶段:压密闭合阶段—线弹性阶段—裂纹稳定扩展阶段—裂纹非稳定扩展阶段—峰后应变与破坏阶段;利用渗流进、出水口双泵设计,在5个渗透压差下利用稳态法测试不同应力作用下岩石渗透率,结果表明在不同渗透压差下岩石渗透率均经历缓慢下降—缓慢增加—快速增长3个阶段,与全应力-应变-渗流曲线规律一致,并与试件内部裂纹发展规律相对应;采用瞬态法测试得不同应力差下渗透率变化规律,与稳态法-渗流规律相一致,由于测试方法不同,瞬态法比稳态法测得岩样渗透率高出1~2个量级,均表明红砂岩属于低渗类岩石;通过对完整岩样施加不同应力差模拟底板岩体状态,发现煤层底板压缩区渗透性减小,膨胀区渗透性增大,随着工作面推进,底板渗透性呈现先减小后增大的趋势,试验结果进一步揭示了随工作面推进底板岩体的渗流特性,为底板突水防治提供了重要的理论依据。In order to study the change rule of floor permeability in the process of coal seam mining,Rock Top multi-field coupling test instrument was used to measure the permeability of red sandstone under different stresses by steady-state and transient methods,and the development and change rule of internal cracks and seepage characteristics during the loading process of red sandstone were analyzed.The results show that the stress difference of the rock sample is equal to 20 MPa,and the stress-strain curve is step-like.According to the crack volume strain method,the strain threshold of each stage of stress-strain can be divided into five stages:compression and sealing stage-linear elastic stage-crack stable growth stage-crack unstable growth stage-post-peak strain and failure stage;using the seepage inlet and outlet of the double pump design,using the method of steady state under five osmotic pressure difference under different stress test of rock permeability and shows that rocks permeability under different osmotic pressure difference are experiencing rapid growth slow decline-slow increase-three stages,with the stress and strain-seepage curve law is consistent,and correspond to specimen internal crack law of development;the permeability variation law under different stress differences measured by the transient method is consistent with that of the steady-state method.Due to different testing methods,the permeability of rock samples measured by the transient method is 1~2 orders of magnitude higher than that measured by the steady-state method,indicating that the red sandstone belongs to the type of low-permeability rock;applying different differential stress simulation based on complete sample floor rock mass state,found that the compression zone coal floor permeability decreases,and expansion zone permeability increase,with the working face advancing,floor permeability shows the tendency of increase with the decrease of the first,the results further reveal the with the working face advancing floor seepage characteri

关 键 词：渗透特性 裂纹扩展 低渗 底板突水 岩石加载 

分 类 号：TD745[矿业工程—矿井通风与安全]