Shear-induced rockburst of double-tunnel rocks subjected to shear loading:A comparative analysis
辛杰 1江权 2翟迪 3丰光亮 2何本国 4李邵军2
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作者信息
1. 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
2. State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,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
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
Key words
shear-induced rockburst/physical model/double-tunnel rocks/discrete element method/tunnel spacing/stress field
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基金项目
National Natural Science Foundation of China(52325905)
Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chi(Z020005)