The Study For PBA Technology On Construction Simulation Of Beijing Metro, Line 16, Suzhou Street Station

With the rapid development of Chinese society, existing road traffic conditions can not meet people’s needs because of the growth of urban traffic flow. Traffic jam has became a serious common problem in city. Subway construction is an effective way to alleviate the problem mentioned, However, due to the limitations of urban underground space where subwayline go through, the traditional excavation method is hard to work out. The PBA method was an advanced solution to it which combines the advantages of traditional shallow mining method and the cover-excavation method with the characteristic of flexibility and adaptability in practice. At present, there are few theoretical research about PBA method with more research results be about double pilot tunnel but other structure type. It has been obstacles for the application and popularization of PBA method.This paper focus on Beijing Subway line 16 Suzhou Street transportation station which construct by single pilot tunnel PBA method. By mean of numerical simulation software MIDAS GTS NX, we simulated the construction process of the station with the PBA method’s characteristic and the use of finite difference method. The main contents are as follows:(1) The simulation result of maximum surface subsidence in different construction stages including small pilot tunnel excavation, construction of pile system, buckle arch construction, excavation of platform layer and the station hall shows that the value of surface subsidence triggered by buckle arch construction is bigger than others followed by the value of surface subsidence triggered by small pilot tunnel excavation. The grouting reinforcement measure taken before excavation can control the surface subsidence effectively.(2) Based on the analysis of surface subsidence in different construction stages, the value of surface subsidence at the station midline is maximum and it is symmetrical about the midline on both sides. The surface subsidence has significant changes within the range of 20 meters along station midline which is consistent with Peck Formula.(3) Stress analysis based on simulation shows that stress distribution during the buckle arch construction stage is most complicate, arch and the pilot tunnel junction is the weak part of the whole structure. Buckle arch construction is the most important stage in the whole construction process. The piles-beams-arches structure constructed by PB A method is of high strength and resistance. It has good practical use in control surface subsidence especially when surroundings environment has high stability requirements.(4) The simulation result of surface subsidence is consistent with the actual result to some extent with less overall error. The results can provide some references for similar subway construction projects in the future.