| 隧道近距大节理硬脆性围岩破裂机理 |
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| 引用本文： | 钟志彬,邓荣贵,孙怡,张志伟,张颖,付小敏.隧道近距大节理硬脆性围岩破裂机理[J].中国公路学报,2018,31(5):106-116. |
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| 作者姓名： | 钟志彬 邓荣贵 孙怡 张志伟 张颖 付小敏 |
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| 作者单位： | 1. 西南交通大学 土木工程学院, 四川 成都 610031;2. 中铁二院工程集团有限责任公司, 四川 成都 610031;3. 四川省建筑职业技术学院 铁道工程系, 四川 成都 610399;4. 成都理工大学 地质灾害防治与地质环境保护国家重点实验室, 四川 成都 610059 |
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| 基金项目： | 国家自然科学基金项目（41272321）；西南交通大学博士生创新基金项目（13017001） |
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| 摘 要： | 为揭示近距大节理硬脆性隧道围岩的破裂机理，采用含天然节理的流纹岩开展双轴压缩试验，获得围岩应力分布特征及渐进破裂过程。PFC2D离散元颗粒流程序模拟了节理围岩和完整围岩在双轴压缩作用下的变形及破裂特征，并与室内试验结果进行对比分析。研究结果表明：双轴压缩作用下，含天然节理的隧道试样表现出显著的脆性破坏特征，节理面起裂发生滑移错动，拱顶和底板围岩逐渐拉裂，宏观破裂面穿过大节理并向隧道拱脚、边墙和试样边界扩展，造成试样的最终失稳破坏；PFC2D数值模拟结果显示，大节理面附近裂隙集中发育，并迅速扩展形成与节理大角度相交的破裂面，试样峰前破裂过程短暂，峰后裂隙加速扩展而承载力急剧下降，数值模拟与试验结果吻合；近距隧道大节理显著影响硬脆性围岩的破裂模式，大节理的剪切滑移引发试样的宏观破裂，靠近大节理的拱脚十分破碎，而边墙则形成“V”形破碎区。研究成果为节理隧道围岩的支护设计和防灾减灾提供参考。
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| 关 键 词： | 隧道工程 围岩稳定 双轴压缩 大节理 离散元 |
| 收稿时间： | 2017-08-08 |
Fracture Mechanism of Hard and Brittle Tunnel Surrounding Rock with Nearby Large Joints |
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| ZHONG Zhi-bin,DENG Rong-gui,SUN Yi,ZHANG Zhi-wei,ZHANG Ying,FU Xiao-min.Fracture Mechanism of Hard and Brittle Tunnel Surrounding Rock with Nearby Large Joints[J].China Journal of Highway and Transport,2018,31(5):106-116. |
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| Authors: | ZHONG Zhi-bin DENG Rong-gui SUN Yi ZHANG Zhi-wei ZHANG Ying FU Xiao-min |
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| Affiliation: | 1. School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, Sichuan, China;2. China Railway Eryuan Engineering Group Co., Ltd., Chengdu 610031, Sichuan China;3. Department of Railway Engineering, Sichuan College of Architectural Technology, Chengdu 610399, Sichuan, China;4. State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, Sichuan, China |
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| Abstract: | To reveal the fracture mechanism of hard and brittle tunnel-surrounding rock near large joints, a biaxial compression test was performed on a rhyolite containing natural joints to obtain the distribution characteristics of surrounding rock stress and progressive fracture process. PFC2D, a discrete element flow, was used to simulate the deformation and fracture process of jointed and intact surrounding rock under biaxial compression, which were compared with the laboratory test results.The results indicate the following:Under the condition of biaxial compression loading, the fracture of the specimen, which contains two natural joints, is significantly brittle. A joint wall is initiated and slipped, and the crown and floor are then tensile fractured. The macro fracture planes traverse the large joints and propagate toward the arch springing, sidewall, and boundary of the specimen, resulting in its failure. The results of a numerical simulation of PFC2D show that cracks concentrate near the large joint walls, where they propagate, becoming macro fracture planes that intersect the joints with a large angle, leading to a failure of the specimen. The specimen then cracks faster and the bearing capacity decreases after the peak strength is reached. The numerical results show a good agreement with the experimental results. The nearby large joints of the tunnel significantly affect the fracture model of hard and brittle surrounding rock. The shear slip of the large joints leads to a macro fracture of the specimen. The arch springing near the lower large joint is significantly fractured, and the sidewall is fractured in a "V" shape. The results can provide reference to the support design and disaster prevention, as well as a reduction of jointed tunnel-surrounding rock. |
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| Keywords: | tunnel engineering stability of surrounding rock biaxial compression large-joint discrete element |
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