压剪荷载作用下双隧道围岩的剪切型岩爆:对比分析  

Shear-induced rockburst of double-tunnel rocks subjected to shear loading:A comparative analysis

作　　者：辛杰 江权 翟迪 丰光亮 何本国 李邵军 XIN Jie;JIANG Quan;ZHAI Di;FENG Guang-liang;HE Ben-guo;LI Shao-jun(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Energy School,Xi’an University of Science and Technology,Xi’an 710054,China;Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines,Northeastern University,Shenyang 110819,China)

机构地区：[1]State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Energy School,Xi’an University of Science and Technology,Xi’an 710054,China [4]Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines,Northeastern University,Shenyang 110819,China

出　　处：《Journal of Central South University》2023年第12期4207-4229,共23页中南大学学报（英文版）

基　　金：Project(52325905)supported by the National Natural Science Foundation of China;Project(Z020005)supported by Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences。

摘　　要：认识剪切型岩爆的触发机理对地下工程科学设计与安全施工具有重要意义。为揭示隧道围岩(DTR)的剪切触发型岩爆机理,进行了砂岩的双矩形隧道和双圆形隧道物理模型剪切试验。在剪切试验过程中,利用高速摄像机和声发射监测仪对DTR的岩爆过程进行监测和记录,揭示了压剪下DTR的宏观和细观断裂特征;进而建立了5种隧道间距数值模型,分析了压剪下含隧洞试样连续-非连续剪切过程及其触发的岩爆机理;提出了一种新的能量冲击指数(S)来评价剪切型岩爆倾向性。试验结果表明,在剪切试验中,DTR的实时剪切特征、内外破裂特征和微裂纹数演化特征可划分为4个典型阶段:整体剪切压缩阶段(Ⅰ阶段)、以裂纹萌生为主的弹性阶段(Ⅱ阶段)、以裂纹扩展-贯通和剪切岩爆为主的剪切破裂阶段(Ⅲ阶段)和剪切摩擦阶段(Ⅳ阶段)。此外,试验结果还表明DTR在剪切型岩爆发生后可形成对称猫耳形缺口;微裂纹演化过程中DTR经历了裂纹预备阶段(Ⅰ阶段)、裂纹初始增长阶段(Ⅱ阶段)、裂纹快速增长阶段(Ⅲ阶段)和裂纹稳定阶段(Ⅳ阶段)。更重要的是,综合分析发现,双矩形隧道和双圆形隧道触发剪切型岩爆机制存在差别的本质是截面形状导致的结构效应,即双矩形隧道和双圆形隧道应力场分布差异导致断裂行为不同。研究结果有利于加深对剪切型岩爆机理的认识,为岩土工程防治提供理论依据。Understanding triggering mechanism of shear-induced rockburst is of great significance for design,construction and operation in underground engineering.To reveal triggering rockburst mechanism in double-tunnel rocks(DTR),double rectangular tunnel(DRT)and double circle tunnel(DCT)physical model shear tests are executed,combined with high-speed cameras and acoustic emission monitor.And five tunnel spacing numerical models are established to investigate the triggering rockburst meso-mechanism based on continuous-discontinuous shear process.In addition,a energy impact index(S)is presented to evaluate shear-induced rockburst proneness.The test results indicate that the shear characteristic,internal and external failure characteristics,and micro-crack number evolution characteristics of DTR can generally be divided into four unified typical stages.In terms of fracture evolution,the shear failure of DTR has experienced shear compression stage,elastic stage dominated by crack initiation,shear fracture stage dominated by crack propagation-coalescence and shear-induced rockburst,and shear friction stage.It is generalized into typical shear model,and it reveals that DTR exhibits a significant characteristic of symmetrical cat-ear shaped notch formed after the shear-induced rockburst.In the aspect of the evolution of micro-cracks,the specimen has crack quiet period,initial crack increase stage,rapid crack increase stage,and crack stability stage.In addition,when the tunnel spacing is greater than 2 times tunnel diameter,the stress concentration phenomenon is significantly optimized.More importantly,the essential triggering shear-induced rockburst mechanism difference between DRT and DCT is the structural effect caused by the section shape,i.e.,the difference in stress field distribution between DRT and DCT leads to different rockburst behaviors.The research results are beneficial for deepening the understanding on mechanism of shear-induced rockburst.

关 键 词：剪切岩爆 物理模型 双隧道围岩 离散元法 隧道间距 应力场 

分 类 号：U451.2[建筑科学—桥梁与隧道工程]