Analysis of the Stress Characteristics and Rock Burst of Ultra Deep Buried Tunnel in Sichuan-Tibet Railway

Research purposes: Ultra deep buried tunnel of Zheduoshan is the controlling key porject of Chengdu to Kangding Railway, which is located in the western section of Chinese famous Y shaped tectonic wedge position. The characteristics of ground stress and rock burst analysis are of great significance for railway route selection, design and construction. In this paper, the Sichuan-Tibet Railway Chengdu to Kangding control engineering of Zheduoshan tunnel as an example, through the data of ground stress test and numerical simulation to analyze the stress distribution characteristics of Zheduoshan tunnel area, and achieve the direction of the maximum principal stress. And through the tunnel rock stress-strain curve under uniaxial loading-unloading to calculate the tendency index of tunnel rock burst, analysis the rock mechanics index of rock burst. Finally, through the deep-hole drilling results, rock mechanics test, numerical simulation analysis and hydrological experiment to analyze Zheduoshan tunnel stress and the rock burst strength. Research conclusions: (1)The maximum principal stress of Zheduoshan tunnel is horizontal stress and the direction is NEE, the measured maximum value is 17 MPa, the maximum numerical simulation' value is 48 MPa; (2)From the analysis of rock burst tendency index test, the surrounding rock has the energy storage and release conditions of the medium to intense rock burst. (3)Through comprehensive analysis, the medium to intense rock burst of Zhuoduoshan tunnel is possible to occur. (4)The research results can provide a basis for the design of the tunnel, and also provide reference for the stability of surrounding rock. © 2017, Editorial Department of Journal of Railway Engineering Society. All right reserved.