锚杆预紧力对锚固岩体力学性能改善的试验研究  

Experimental study on improvement of mechanical properties of anchored rock mass by bolt preload

作　　者：侯公羽[1] 邵耀华 张世欧 赵铁林 刘春雷 HOU Gongyu;SHAO Yaohua;ZHANG Shiou;ZHAO Tielin;LIU Chunlei(School of Mechanics and Civil Engineering,China University of Mining and Technology(Beijing),Beijing 100083,China)

机构地区：[1]中国矿业大学(北京)力学与土木工程学院,北京100083

出　　处：《岩石力学与工程学报》2025年第2期261-275,共15页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金委员会与2020年度高速铁路基础研究联合基金资助重点项目(U2034205)~~。

摘　　要：为研究预紧力锚杆对完整岩体及含裂隙岩体力学性能的影响,开展不同预紧力锚杆支护条件下完整岩体的单轴压缩试验和含裂隙岩体的直剪试验,并结合声发射技术揭示岩体内部裂纹演化特征。单轴压缩试验结果表明:(1)与无支护试件相比,极低预紧力和低预紧力支护时完整岩体强度基本无变化,中等预紧力和高预紧力支护时完整岩体强度显著增大。(2)无支护、极低预紧力和低预紧力锚杆支护下岩体呈明显的单斜面剪切破坏;随锚杆预紧力的增大,锚固体破坏模式由剪切破坏转变为张拉劈裂破坏,这一破坏特征与声发射RA-AF值表征的裂纹类型相对应。直剪试验结果表明:(1)预紧力锚杆可显著提高含裂隙岩体的承载性能,随锚杆预紧力的增大,含裂隙锚固体的抗剪强度逐渐增大。(2)通过声发射信号分析,揭示直剪加载过程中含裂隙锚固体的裂纹演化模式;在加载初期,张拉和剪切裂纹比例相近;随加载的持续进行,剪切裂纹占主导地位。研究成果可为研究主动支护的作用机制及锚杆支护设计提供理论基础。Prestressed anchor rods exhibited effects on the mechanical properties of intact rock mass and fractured rock mass.Uniaxial compression tests of intact rock mass and direct shear tests of fractured rock mass were conducted under different pretension anchor rod support conditions.Additionally,the crack-changing characteristics inside the rock mass were revealed by acoustic emission.The results of uniaxial compression tests show that compared with unsupported rock mass,the changes in compressive strengths of intact rock mass exhibited unobvious under ultra-low and low pretension supporting conditions,while the compressive strengths were significantly improved by medium and high pretension supporting.The rock mass showed obvious single-inclined plane shear failure under no support and ultra-low to low pretension bolt support conditions.Specifically,as the pretension force of the anchor bolt increased,the failure mode of the anchor rock masses changed from shear failure to tension splitting failure.These failure characteristics aligned with the crack type characterized by the RA-AF value.The results of direct shear tests show that the pretension bolt could enhance the bearing performance of fractured rock mass.The shear strength of fractured rock mass increased with the increase in the pretension force of anchor bolts.The crack evolution mode of anchor fractured rock mass during shear loading was revealed through acoustic emission signal analysis. At the initial loading stage,the proportion oftensile cracks was close to that of shear cracks. As the progress of loading continued,the shear crack becamedominant. This work could provide theoretical basis for studying the mechanism of active support and the designof anchor support.

关 键 词：岩石力学 锚固岩体 预紧力锚杆 力学响应 声发射 

分 类 号：TU45[建筑科学—岩土工程]