弱动力扰动作用下岩石微裂隙演化特征及灾害防控  

Evolutionary characteristics of microcracks in rocks under weak dynamic disturbance and disaster prevention and control

作　　者：姜明伟 梁运涛[1] 冯文彬 李海涛[3] 周睿 郭宝龙 刘洋 马举[6] JIANG Mingwei;LIANG Yuntao;FENG Wenbin;LI Haitao;ZHOU Rui;GUO Baolong;LIU Yang;MA Ju(China Coal Research Institute,Beijing 100013,China;CCTEG Shenyang Research Institute,Fushun 113000,China;Deep Mining and Rock Burst Research Branch,Chinese Institute of Coal Science,Beijing 100013,China;College of Safety and Environmental Engineering,Shandong University of Science and Technology,Qingdao 266000,China;Deep Mining Laboratory of Shandong Gold Group Co.,Ltd.,Yantai 266000,China;School of Resources and Safety Engineering,Central South University,Changsha 410083,China)

机构地区：[1]煤炭科学研究总院,北京100013 [2]中煤科工集团沈阳研究院有限公司,辽宁抚顺113000 [3]煤炭科学研究总院有限公司深部开采与冲击地压防治研究院,北京100013 [4]山东科技大学安全与环境工程学院,山东青岛266000 [5]山东黄金集团深井开采实验室有限公司,山东烟台266000 [6]中南大学资源与安全工程学院,湖南长沙410083

出　　处：《煤田地质与勘探》2024年第10期166-176,共11页Coal Geology & Exploration

基　　金：国家自然科学基金面上项目(5217042662);国家自然科学基金联合基金项目(U23B2094);国家重点研发计划项目(2023YFB3211000,2022YFC2904104)。

摘　　要：【目的】高应力叠加弱动力扰动是诱发冲击地压的关键因素,但不同扰动幅值、频率、卸载范围下的岩石微裂纹扩展特征和能量耗散规律尚不明确,无法为冲击地压防治提供技术支撑。【方法】基于真三轴卸载动力扰动试验,分析了不同扰动幅值(5、10 MPa)、频率(4、10 Hz)、三向应力卸载(0、12MPa)下深部围岩失稳破坏规律,并结合SEM扫描分析了岩石微裂隙特征。通过锚杆拉拔试验,优化了锚杆肋间距和肋高,提高了其吸能支护作用,提出了“吸能锚杆-低阻抗混凝土注浆-喷浆-挂网”组合支护技术。利用传感器对巷道进行长期监测,得到治理前后压力与振动数据。【结果和结论】研究表明:(1)随着扰动幅值和频率的增加,裂纹增加显著且不规则,岩石断口的方向分形维数降低。当扰动为10MPa、10Hz时,分形维数降至最低值0.62,孔隙方向角80°~120°孔隙定向频率达到最大值的52%,约为原始岩石的1.68倍。说明岩石受扰动后颗粒的应力不均匀,导致应力集中,断裂方向明显。(2)随着扰动幅值和频率的增加,SEM图像的微孔隙面积先快速增加,后缓慢增加且增加趋势越来越小。扰动频率每增加2 Hz,岩石微裂隙面积增加约24.13%。(3)现场测试表明随着锚杆肋间距和肋高增加,拉拔曲线形态由“弹塑性阶段-破坏失效阶段-残余阶段”逐渐过渡为“弹塑性阶段-微量屈服阶段-大量强化阶段-破坏失效阶段-残余阶段”,肋间距48mm、肋高2mm的螺纹钢锚杆吸能效果最好。经现场监测可将巷道压力稳定在36 N左右,峰值加速度控制在8000mm/s^(2)以内。研究揭示了卸载动力扰动作用下围岩破坏及能量释放规律,提出的“吸能锚杆-低阻抗混凝土注浆-喷浆-挂网”支护技术,可为类似深部工程提供理论指导。[Objective]High stress with superimposed weak dynamic disturbance serves as a critical factor including rock bursts.However,the microcrack propagation characteristics and energy dissipation pattern of rocks under different disturbance amplitude,frequencies,and unloading ranges remain unclear,leading to a lack of technical support for rock burst prevention and control.[Methods]Based on the true triaxial unloading dynamic disturbance tests,this study ana-lyzed the instability failure patterns of deep surrounding rocks under different disturbance amplitude(5,10 MPa),fre-quencies(4,10 Hz),and triaxial stress unloading(0,12 MPa).Moreover,this study examined the characteristics of mi-crocracks in rocks using scanning electron microscopy(SEM).Through bolt pull-out tests,this study enhanced the en-ergy-absorbing support effects of bolts by optimizing the rib spacing and height of bolts.Accordingly,it proposed a combined support technique integrating energy-absorbing bolts,low-impedance concrete grouting,guniting,and screen-ing.Additionally,the pressure and vibration data of roadways before and after treatment were obtained through long-term monitoring using sensors.[Results and Conclusions]Key findings are as follows:(1)With an increase in disturb-ance amplitude and frequency,cracks increased significantly and irregularly,and the fractal dimension of rock fracture direction decreased.In the case of disturbance of 10 MPa and 10 Hz,the fractal dimension decreased to the lowest value of 0.62,with the orientation frequency of pores at angles ranging from 80°to 120°reaching the maximum value of 52%,which was about 1.68 times that of the original rocks.This finding suggests that the uneven stress distribution of rock particles after disturbance led to stress concentration and pronounced fracture direction.(2)With an increase in disturb-ance amplitude and frequency,the micropore areas revealed by SEM images shifted from a rapid growth to a slow growth,with the increasing amplitude decreasing gradually.Every increase of 2 Hz i

关 键 词：真三轴试验 冲击地压 SEM扫描 微裂隙 吸能锚杆 弱动力扰动 

分 类 号：TD317[矿业工程—矿井建设]