| 岩桥直剪细观破坏特征与剪胀效应研究 |
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| 引用本文： | 孙祥,陈国庆,张广泽,王栋,秦昌安.岩桥直剪细观破坏特征与剪胀效应研究[J].工程地质学报(英文版),2020,28(2):246-254. |
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| 作者姓名： | 孙祥 陈国庆 张广泽 王栋 秦昌安 |
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| 作者单位： | ①.地质灾害防治与地质环境保护国家重点试验室(成都理工大学)，成都 610059，中国 |
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| 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) |
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| 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。
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| 关 键 词： | 岩石力学 直剪 节理岩体 剪胀效应 |
| 收稿时间： | 2019-01-21 |
MICROSTRUCTURE FRACTURE CHARACTERISTICS AND DILATANCY EFFECT OF ROCK BRIDGE UNDER DIRECT SHEAR TESTS |
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| SUN Xiang,CHEN Guoqing,ZHANG Guangze,WANG Dong,QIN Chang an.MICROSTRUCTURE FRACTURE CHARACTERISTICS AND DILATANCY EFFECT OF ROCK BRIDGE UNDER DIRECT SHEAR TESTS[J].Journal of Engineering Geology,2020,28(2):246-254. |
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| Authors: | SUN Xiang CHEN Guoqing ZHANG Guangze WANG Dong QIN Chang an |
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| Institution: | ①.State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China②.China Railway Eryuan Engineering Group Co., Ltd., Chengdu 610031, China |
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| Abstract: | The jointed rock masses with incomplete end joints and coalescence mechanisms of rock slopes are often encountered in engineering construction. They are complex. In order to reveal the relationship between the failure characteristics and dilatancy effect of end rock bridge under different joint connectivity rates and normal stresses, we carry out the direct shear test of the rock bridge to explore the failure process of the front locked section slope. The whole process of shear stress change is analyzed by high-speed photography and AE characteristic parameters. After test, we find that the shear failure process of the end direct shear specimens can be divided into five stages: crack compaction, stable crack propagation, progressive propagation, strain softening and residual strength stage. The decrease of joint connectivity rate and the increase of normal stress lead to the increase of peak shear displacement and peak shear stress. The joint connectivity rate and normal stress have significant influence on the failure characteristics of rock mass. When the joint connectivity rate is high and the normal stress is small, the cracks propagate in a straight line. With the decrease of the length of joint connectivity rate, the phenomenon of shear dilatancy occurs, and the cracks become irregular curves. Meanwhile, the increase of normal stress causes the dilatancy phenomenon to fluctuate. The AE characteristics are consistent with the rock bridge crossing process. The peak number of AE events increases with the decrease of the joint connectivity rate and the increase of normal stress. The tests demonstrate that the microscopic failure characteristics and dilatancy effect of rock bridge are extremely significant for studying the failure mechanism of the locked section slope as a guide. |
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| Keywords: | Rock mechanics Direct shear Joint rock Dilatancy effect |
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