Based On Block Theory To Analyze The Stability Of Tunnel Surrounding Rock And Optimize The Supporting Scheme

To analyze the stability of surrounding rock is one of key technical problems of tunnel construction. The block theory has its unique advantages in the analysis of stability of surrounding rock than other analysis methods, which is widely used in rock engineering. However, just like other methods, block theory also has its drawbacks, how to combine block theory with numerical analysis methods to analysis of the stability of surrounding rock and support design is become one of hot issues in the underground engineering. Aimed at the aforementioned problems, relying on the Kuiba Road 2nd tunnel engineering of Shenzhen, the "Based on block theory to analyze the stability of tunnel surrounding rock and optimize the supporting scheme" was proposed in this paper, and the systematic study conducted on the existing research work.(1) Summarized the research methods of stability of surrounding rock and latest research of block theory in detail, introduces the fundamental of block theory.(2) Selected three representative groups of structural planes according to the geological survey data of tunnel combined with face description of tunnel. The use of block theory binding occurrences of structural plane to analysis surrounding rock range segment in the left role of Kuiba Road 2nd tunnel engineering of Shenzhen, found out the block range this segment, and these blocks are analyzed in order to identify the key block among biggest region, calculate the sliding surface, the sliding force and the factor of security. Among them, using segmentation method to solve the volume of surface and sliding surface area of block, to match with the actual situation as much as possible.(3) Using Unwedge program calculated the position, volume and the safety factor of the block, and comparing with the analytical solution by block theory, improving that the program could use of the principle of block theory to analyze the stability of surrounding block very well; meanwhile, using Unwedge program analog the support under different circumstances, obtained the optimal support program under Unwedge program, and verify the feasibility of the support program of design.(4) Simulated the excavation by block theory, optimized the support of tunnel by FLAC3D numerical analysis method.(5) Simulated the excavation process when it have blocks or not in tunnel through numerical analysis method, and obtained the vertical displacement of the head and bottom of tunnel, and the vertical displacement under 24 kinds of support programs. Compared with support program of design, got the best supporting scheme of block in this section.Through the advanced theoretical methods, the analysis of stability of surrounding rock and optimization of support parameters of tunnel were studied in this paper, the work has a high practical value in engineering applications, provides effective analytical measure to analysis of stability of surrounding rock and chooses the best supporting program systematically.