基于声发射的含锚固缺陷节理试样单轴压缩破裂机制研究  

Investigation on fracture mechanism of anchored rock with anchor defect and existing joint under uniaxial compression based on acoustic emission

作　　者：占赛 关凯[1] 朱万成[1] 张鹏海[1] 周健毓 ZHAN Sai;GUAN Kai;ZHU Wancheng;ZHANG Penghai;ZHOU Jianyu(School of Resources and Civil Engineering,Northeastern University,Shenyang 110819,China)

机构地区：[1]东北大学资源与土木工程学院,辽宁沈阳110819

出　　处：《采矿与岩层控制工程学报》2024年第4期76-86,共11页Journal of Mining and Strata Control Engineering

基　　金：国家自然科学基金资助项目(52004053,U1906208)。

摘　　要：锚固缺陷会弱化锚杆对节理岩体的支护效果,为探究锚固缺陷对锚固节理试样的锚固效应,对含不同锚固缺陷的锚固节理试样开展了单轴压缩试验,结合声发射、分布式光纤和DIC监测技术,分析了试样在不同破裂演化阶段时的声发射信息,得到了其破裂前兆特征。研究结果表明:锚固缺陷的存在降低了锚固节理试样的单轴抗压强度、峰值应变和声发射能量释放;在加载后期全长锚固节理试样声发射主频的高、低频信号都出现了增长,锚固缺陷试样主要是声发射主频的高频信号增长,且中间缺陷较端部缺陷会出现更高频段的声发射主频;全长锚固节理试样沿节理发生宏观剪切破坏;中间锚固缺陷试样的锚杆对裂纹控制作用较为迟缓,沿着节理发生宏观拉伸破坏;当锚固缺陷在试样一侧时该侧锚杆的变形大于对称侧,节理尖端的反翼裂纹向锚固缺陷一侧发生偏转并与锚固缺陷贯通,最终导致试样发生失稳破坏。持续高能的声发射能量释放,声发射峰值频率分布主频段增加,峰值频率呈降低趋势,声发射b值整体呈波动降低趋势,可作为试样发生失稳破裂的前兆特征。研究成果可为锚杆在节理裂隙岩体中的支护加固提供参考。The anchor defects weaken the anchoring effect on jointed rock mass.In order to investigate the influence of anchor defects on the anchoring effect of joint specimens,uniaxial compression tests were conducted on rock specimens with different anchor defects.Combining with acoustic emission,distributed fiber optic,and Digital Image Correlation(DIC)monitoring technologies,the acoustic emission information of the bolted rock specimens at different stages of fracture evolution was analyzed to explore their precursor characteristics.The results indicate that the anchor defects reduce the uniaxial compressive strength,peak strain,and acoustic emission energy release of the bolted rock joint specimens.In the later stages of loading,both high and low⁃frequency signals of main frequencies of acoustic emission increase in fully anchored rock joint specimens.In contrast,main frequencies of acoustic emission of rock joint specimens with anchor defects primarily increase in high⁃frequency signals.Moreover,rock specimens with intermediate defects show higher frequency bands in main frequencies of acoustic emission when compared to rock specimens with defects at the ends.The fully anchored rock joint specimens experience macroscopic shear failure along the joint,while the bolt on the rock specimens with intermediate anchor defects result in a delayed crack control effect,leading to macroscopic tensile failure along the joint.When the anchor defect is on one side of rock specimen,the deformation of the bolt on that side is greater than that of the symmetric side.The antiwing crack at the joint tip deviates towards the side with the anchor defects and penetrate with the anchor defects,eventually leading to specimen instability and failure.It can be served as the precursor information for the unstable fracturing of rock specimens with anchor defects through continuous high⁃energy acoustic emission,an increase in the main frequency range of acoustic emission peak distribution with a decreasing trend,and a continuous and fluctu

关 键 词：锚固缺陷 锚固节理试样 声发射 破裂演化 前兆特征 

分 类 号：TD23[矿业工程—矿井建设]