Model Test Research On Construction Of Tunnel Wth Pre-lining Method And Structure Design Research

Surrounding pre-lining method,model test of construction process and the comparison of construction methods and pre-lining design and the second lining design load have been researched roundly in this paper. The research methods include numerical simulation and model test and theoretical analysis. This privides technical reserves for the large scale application of the construction method in China in the future. The main work and research results are as follows:(1) In virtue of 1:10 large-scale model test,detailed experimentation scheme has been designed and implemented for the the construction process of the pre-lining method.It gets the general variational rule of soil pressure around tunnel, soil vertical displacement and pre-lining strain in the construction process. At the same time, by Midas software, the construction process of the pre-lining method is simulated. As compared with the result of the numerical simulation and the result of model test have showed the qualitative rules. Accroding to analysis, it is considered that using the pre lining method to build a tunnel, the excavation supporting process of pre-cutting cause larger soil disturbance, and the soil excavation of the whole section causes little soil disturbance, soil pressure and the upper soil deformation mianly produced the excavation supporting process of pre-cutting.(2) Comparing the numerical simulation result of pre-lining method and the numerical simulation result of common method, it shows that the pre-lining method is obviously better than the common method in control of soil deformation, supporting force and plastic zone in sand-clay strata.(3) Selcting xidan-lingjinghutong tunnel of Beijing No.4 subway as the research object, with load structure model,stratum structure model and project comparition,we finally determined that the thickness of pre-lining is 30cm when it builts a 6 metres span tunnel by the pre-lining method in 11m buried deep strata in Beijing and it can meet requirements.for safety.(4) The second lining design load is researched with the numerical simulation method.Based on soil pressure arch theory,it gives methods how to determine the second lining design load.