• 论文
主办单位:煤炭科学研究总院有限公司、中国煤炭学会学术期刊工作委员会
正交型交叉裂隙岩石强度特征与破裂机理试验研究
  • Title

    Experimental investigation on the strength characteristics and fracture mechanism of rock with orthogonally crossed cracks

  • 作者

    武旭 王帆 席迅 郭奇峰 孙景来 王新灵

  • Author

    WU Xu1 ,WANG Fan1 ,XI Xun2,3 ,GUO Qifeng2 ,SUN Jinglai1 ,WANG Xinling1

  • 单位

    北京市市政工程研究院北京科技大学 土木与资源工程学院英国思克莱德大学 土木与环境工程学院

  • Organization
    1. Beijing Municipal Engineering Research Institute,Beijing  100037,China; 2. School of Civil and Resource Engineering,University of Science and Technolo- gy Beijing,Beijing  100083,China; 3. Department of Civil and Environmental Engineering,University of Strathclyde,Glasgow G11XJ,United Kingdom
  • 摘要

    工程岩体是具有各向异性的非均匀地质体,隧道开挖或服役过程中由于岩体节理、裂隙诱发的片帮、冒顶等事故时有发生,造成严重的人员伤亡和经济损失。天然岩体中裂隙主要以交叉形态分布,为了探究裂隙对岩石力学特性及破裂特征的影响规律,利用线切割设备对岩石试样预制不同分布状态的正交型交叉裂隙,借助声发射和表面应变测量系统对单轴压缩条件下裂纹起裂应力、裂纹扩展路径与应力性质进行计算与分析。研究结果表明,裂隙长度对岩石强度的影响作用较小,裂隙与加载方向的夹角是影响岩石强度的最主要因素。岩石峰值强度与弹性模量均随主裂隙倾角的增大呈先增加后减小的变化规律,当主裂隙倾角α=90°时,岩石试样的力学指标达到最小值;正交型裂隙试样中主裂隙或次裂隙端部更容易产生起裂破坏,起裂位置与预制裂隙倾角息息相关;裂隙岩石的破裂具有显著方向性,正交型裂隙岩石的起裂裂纹主要呈翼型或反翼型,当α<45°时,主裂隙对起裂起到主控作用,次裂隙的存在对裂纹扩展具有导向作用;当α>45°时,起裂裂纹主要位于次裂隙端部,起裂由次裂隙控制。与完整试样相比,裂隙岩石试样整体失稳破坏前产生多次声发射突增现象,即加载过程中产生多次破裂,正交型裂隙试样起裂应力集中于0.22σc~0.34σc,起裂发生在较低应力水平;当岩石中存在与加载方向垂直的裂隙时,岩石的破裂与破坏受此类裂隙的影响最为显著。

  • Abstract
    Rock mass is a typical kind of engineering geological materials with the heterogeneity and anisotropy. The failure disasters of tunnels (e. g. ,roof falling and wall collapse) are related with the joints and cracks in rock,which may lead to serious casualties and economic losses. Cracks in natural rock are distributed in cross shapes. In order to inves-tigate the effects of crossed cracks on the mechanical properties and failure characteristics of rock,a wire cutting equipment is employed to make the rock specimens with different crossed cracks,then an acoustic emission system an digital image correlation technique are used to study the fracture process of rock specimens under uniaxial compres- sion. It has been found that the length of pre-existing cracks has little effect on the rock strength while the angle be- tween the crack and loading direction significantly affects the rock strength. When the angle of primary crack is 90°, the values of rock mechanical parameters reach minimum. Crack initiation is prone to occur at the tips of pre-existing primary and secondary crack,and the crack initiation location is closely related to the angles of pre-existing cracks. The load-ing-induced cracks for the specimens with crossed cracks are Wing or oblique Wing cracks. When the angle of primary crack is smaller than 45°,the pre-existing primary crack determines crack initiation while the pre-existing secondary crack affects the crack propagation. When the angle of primary crack is larger than 45°,crack initiation is more prone to occur around the pre-existing secondary crack and loading makes rock fracture in serval times. The crack initiation stress is about 0. 22-0. 34 times of rock strength. Rock failure process is most significantly affected by the pre-existing cracks perpendicular to the loading direction.
  • 关键词

    正交型裂隙强度特征单轴压缩裂纹起裂裂隙倾角扩展路径

  • KeyWords

    orthogonal crack;strength characteristics;uniaxial compression;crack initiation;crack dip angle;propaga- tion path

  • DOI
  • Citation
    WU Xu,WANG Fan,XI Xun,et al. Experimental investigation on the strength characteristics and fracture mechanism of rock with orthogonally crossed cracks[J]. Journal of China Coal Society,2020,45(7):2681-2690.
  • 图表
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    • 预制裂隙分布位置

    图(14) / 表(0)

相关问题

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