Discussion on size effect of rock burst risk in deep buried tunnel
LIU Ning1,2,ZHANG Chunsheng1,CHU Weijiang1,2,NI Shaohu1
(1. PowerChina Huadong Engineering Corporation Limited,Hangzhou,Zhejiang 311122,China;
2. HydroChina Itasca Research and Development Center,Hangzhou,Zhejiang 310014,China)
Abstract:Rock burst is a key problem in the engineering construction. An accurate forecast and assessment of rock burst risk is crucial. The actual rock burst occurred in the deep buried tunnel group of Jinping II with 7 tunnels of different diameters and total length more than 16 km. The rock burst tendency test was carried out and the stress condition,stress path,energy storage depth and releasing energy were investigated. The test of rock burst tendency is based on the mechanical properties of rock in small scale,which is difficult to reflect the influence of geostress on rock burst risk,so the method has some limitations. Accordingly,the stress and the energy analysis method are able to reveal accurately the problems of size effect. The results based on the mechanical characteristics,the stress path,the energy storage capacity and the energy releasing analysis of deep buried marble show that the drainage tunnel of 7 m diameter has a higher risk of rock burst than the traffic tunnel of 6 m diameter and the diversion tunnel of 13 m diameter. This proves that there is no linear relation between the rock burst and size. According to the actual statistical data,the ratio of rock burst and the proportion of strong to super strong rock burst of the drainage tunnel are also higher than those of the traffic and diversion tunnels. The frequency and intensity of rock burst of the traffic tunnel and diversion tunnel are in the same level,and the result is consistent with the theoretical analysis.
刘 宁1,2,张春生1,褚卫江1,2,倪绍虎1. 深埋隧洞岩爆风险尺寸效应问题探讨[J]. 岩石力学与工程学报, 2017, 36(10): 2514-2521.
LIU Ning1,2,ZHANG Chunsheng1,CHU Weijiang1,2,NI Shaohu1. Discussion on size effect of rock burst risk in deep buried tunnel. , 2017, 36(10): 2514-2521.
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