Study On The Long Term Influence Law And Design Method Of Railway Tunnel Structure With Serious Press Great Deformation

With the rapid development of the national economy,more and more tunnels will be built in the western mountainous area.The tunnel develops towards the direction of " long,big,deep-buried and difficult ".Therefore,in the process of construction and operation,tunnels often are faced with a lot of complicated engineering and technical problems.The problem of press great deformation caused by soft rock with high ground stress is especially prominent.According to the literature at home and abroad,in view of the design and construction stage of the railway tunnel with press great deformation,there has been a lot of in-depth research.In the operation stage,the long-term influence law of the lining structure of the railway tunnel with press great deformation needs to be further studied.Based on the scientific research project of research on the key technology of the construction of Sichuan-Tibet Railway,this paper studies the railway tunnel with serious press great deformation.The main research work is as follows:(1)Through literature research,the law of damage and deterioration of tunnel structure is clarified by the long term effect of train load,and the long-term effect of surrounding rock creep effect on the load and safety of tunnel structure is obtained.(2)Based on the basic theory of damage mechanics and using the finite element software ANSYS Workbench to simulate the fatigue damage of the train load,the damage and deterioration analysis method of the secondary lining of the railway tunnel is established,and the damage development distribution law of the secondary lining of the three sections,single line,round and double line,is obtained,and the stiffness attenuation of the secondary lining structures is explored.The influence law of the strength-stress ratio on the damage of the secondary lining is clarified.(3)By using the Burgers creep model,the creep load development and distribution law of the secondary lining of the railway tunnel with serious press great deformation are obtained,and the influence law of the tunnel section form and the strength-stress ratio on the creep load of the secondary lining is clearly defined.(4)Based on the long-term attenuation law of the stiffness of the secondary lining and the long-term development law of the creep load,the load structure model of the solid element is set up.The long-term change law of the safety of the secondary lining of the railway tunnel is given,and the optimal section form of the railway tunnel with serious press great deformation is obtained.At the same time,the optimal design method of single and double line tunnel section is put forward.