岩桥直剪细观破坏特征与剪胀效应研究

孙祥 陈国庆 张广泽 王栋 秦昌安

孙祥, 陈国庆, 张广泽, 等. 2020. 岩桥直剪细观破坏特征与剪胀效应研究[J]. 工程地质学报, 28(2): 246-254. doi: 10.13544/j.cnki.jeg.2019-039
引用本文: 孙祥, 陈国庆, 张广泽, 等. 2020. 岩桥直剪细观破坏特征与剪胀效应研究[J]. 工程地质学报, 28(2): 246-254. doi: 10.13544/j.cnki.jeg.2019-039
Sun Xiang, Chen Guoqing, Zhang Guangze, et al. 2020. Microstructure fracture characteristics and dilatancy effect of rock bridge under direct shear tests[J]. Journal of Engineering Geology, 28(2): 246-254. doi: 10.13544/j.cnki.jeg.2019-039
Citation: Sun Xiang, Chen Guoqing, Zhang Guangze, et al. 2020. Microstructure fracture characteristics and dilatancy effect of rock bridge under direct shear tests[J]. Journal of Engineering Geology, 28(2): 246-254. doi: 10.13544/j.cnki.jeg.2019-039

岩桥直剪细观破坏特征与剪胀效应研究

doi: 10.13544/j.cnki.jeg.2019-039
基金项目: 

国家自然科学基金项目 41572283

国家自然科学基金项目 41972284

国家重点研发计划 2017YFC1501301

中铁二院工程集团有限责任公司科研项目 KYY2018010(18-19)

详细信息
    作者简介:

    孙祥(1996-),男,硕士生,主要从事岩石力学及岩桥性质方面的研究. E-mail:743486856@qq.com

    通讯作者:

    陈国庆(1982-),男,博士,教授,主要从事地质灾害防治和岩石力学方面的教学与研究工作. E-mail: chgq1982@126.com

  • 中图分类号: TD313

MICROSTRUCTURE FRACTURE CHARACTERISTICS AND DILATANCY EFFECT OF ROCK BRIDGE UNDER DIRECT SHEAR TESTS

Funds: 

the National Natural Science Foundation of China 41572283

the National Natural Science Foundation of China 41972284

the National Key Research and Development Program of China 2017YFC1501301

China Railway Eryuan Engineering Group Co., Ltd. Funding KYY2018010(18-19)

  • 摘要: 节理岩体的剪切贯通机制影响着边坡的稳定性。为揭示锁固段型非贯通节理岩体在不同连通率和法向应力下的破坏特征,在室内直剪试验中结合高速摄影与AE特征参数分析其剪切全过程及剪胀效应。结果表明:节理岩体直剪试验中,法向应力的增大及节理连通率的下降会致使峰值剪切应力及峰值剪切位移增大;节理连通率与法向应力对其破坏特征具显著影响,表现为节理连通率较高且法向应力较小时呈直接剪断的特性,节理连通率降低后呈拉剪复合破坏,出现剪胀现象,而法向应力的增大使得剪胀效应呈波动现象;AE特征与岩桥贯通过程一致,事件数峰值随节理连通率的降低及法向应力的增大而增大且位于峰后。试验得到的岩桥细观破坏特征与剪胀效应对研究锁固段型岩质边坡的贯通破坏机制具指导意义。
  • 图  1  节理岩体试样

    Figure  1.  Joint rock sample

    图  2  加载系统、AE以及高速摄像机布置

    Figure  2.  Loading system, digital AE system and high speed camera layout

    图  3  AE探头布置

    Figure  3.  Digital AE system sensor layout

    图  4  直剪全过程剪切应力-剪切位移曲线

    a.法向应力0.70 MPa,节理连通率50%;b.节理连通率50%;c.节理连通率60%;d.节理连通率70%;e.节理连通率80%

    Figure  4.  Curve of shear stress-shear displacement in the whole process of direct shear

    图  5  微观凸起体作用

    Figure  5.  Microconvex effect

    图  6  法向应力0.85 MPa剪切应力-剪位移曲线

    Figure  6.  Shear stress-shear displacement curve under normal stress 0.85 MPa

    图  7  节理连通率-峰值剪应力曲线

    Figure  7.  Joint connectivity-shear stress curve

    图  8  切向位移-法向位移曲线

    a.节理连通率60%;b.节理连通率70%;c.节理连通率80%

    Figure  8.  Tangential displacement-normal displacement curve

    图  9  节理岩体直剪试验加载及端部受力示意图

    Figure  9.  Diagram of loading and end force in direct shear test of jointed rock mass

    图  10  微元A应力状态

    Figure  10.  Stress state of element A

    图  11  节理连通率—AE峰值事件数

    Figure  11.  Joint connectivity rate vs AE peak event number

    表  1  剪胀阶段割线斜率

    Table  1.   Secant slope in dilatancy stage

    节理连通率
    /%
    法向应力/MPa
    0.7 0.85 1 1.15 1.3
    60 0.333 0.341 0.312 0.266 0.355
    70 0.331 0.110 0.154 0.109 0.073
    80 0 0 0.133 0 0
    下载: 导出CSV

    表  2  不同节理连通率下的3种剪切破坏模式

    Table  2.   Three shear failure modes with different joint connectivity

    破坏方式 破坏过程及特征 示意图 破坏照片
    直接剪断 试样破坏的初裂纹很小,且与剪切面小角度相交,甚至无初裂纹。岩桥直接剪断破坏,剪胀效应不明显,岩桥破坏面较平直,粗糙度较小
    压致拉裂
    后剪断
    在未施加剪切位移之前,试样就出现有压制拉裂,裂纹由岩桥端部发育,之后岩桥剪断
    剪胀剪断 破坏面近于弧形,在剪切过程中拉裂纹的连通会导致掉快现象,剪胀效应也变得更为明显
    下载: 导出CSV

    表  3  特征曲线

    Table  3.   Acoustic emission characteristic curve

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出版历程
  • 收稿日期:  2019-01-21
  • 修回日期:  2019-11-09
  • 刊出日期:  2020-04-25

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