Research On The Secondary Lining Support Time And Stability Control Of Surrounding Rock In Deep Buried Tunnel

The increase of the excavation depth of the railway tunnel, the large ground pressure, the complex geological conditions, the lack of the correct theoretical guidance, the design and construction process of the existence of a large blindness, resulting in the collapse of the tunnel lining often occurs. This has become a major technical problem to be solved in tunnel construction. At home and abroad, the research on tunnel lining collapse is mainly focused on the mechanism of support structure, the stability and the re repair of the damaged structure. There are some limitations in the research on the mechanism and stability of the two lining of the tunnel, and there are few studies on the optimal timing of the two lining support.Appropriate support time for the two intercity railway tunnel lining are analyzed, with the Qingdao blue Silicon Valley Laoshan Intercity Railway Tunnel Engineering Based on the measured data through on-site monitoring, and the finite difference software FLAC3D of tunnel excavation is simulated and analyzed, and the final test results and simulation results combined two, appropriate support time of concrete analysis of tunnel lining. In this paper, the time of the two lining of intercity railway tunnel is mainly studied:(1) Through theoretical research, through theoretical analysis,detailed analysis of deep buried tunnel two lining bearing type, analysis under different loads, load characteristics of two lining structure;analysis of failure characteristics of two lining structure under load,especially the evolution and distribution of the two lining cracks,according to crack in different parts of different types, the characteristics of evolution, influence factors were the impact of tunnel from design,construction materials and other aspects of deformation and failure of deep buried tunnel.(2) Through theoretical analysis, analysis of the impact factors on lining construction are introduced in detail, the step of determining the mechanism and method of lining supporting time of two times, and from the three aspects of supporting force, rate of deformation and displacement analysis of lining reasonable supporting time principle;considering the influence of various factors, the establishment of in accordance with the actual situation of the optimal supporting time of analytical formulae in rock parameters are known, can calculate the wall surrounding the roadway deformation, analyzed deformation data of surrounding rock monitoring and practical engineering to the accurate understanding of the change of surrounding rock, determined the two lining time from the theory to solve the two deep buried tunnel lining support time problem(3) Through the finite element analysis software FLAC3D, to simulate the excavation of Laoshan tunnel, in the process of simulation,analysis of the deformation of the surrounding rock stress release rate and the tunnel tunnel lining under different stress, obtained the support time best supports two lining of Laoshan tunnel, the use of monitoring and measuring technology Study on the process of tunnel excavation,tunnel convergence and vault settlement, and compared with FLAC3D data, calculate the rational application of two lining time, verify the correctness of the analytical formula.