Parameters Optimization Of Supporting System Of Deep Excavation In Metro Station

With the rapid development of urban construction, many cities have the rise of construction of the metro, and a large number of deep excavations also will be there. Design supporting system is a key part of deep excavation in metro station and whether its design is reasonable or not directly affects the safety, economics and construction progress of excavations.Relying on the Yangsi station of metro Yangpu Line in Shanghai, the paper optimized the supporting system parameters of deep excavation in metro station,the main content and conclusions are as follows:(1)Summed up the supporting systems commonly used in deep excavation , and analyzed their advantages and disadvantages. Proposed the supporting systems for deep excavation in metro station.(2)Analyzed and summarized the support joints commonly used in deep excavation. On the basis of the comparison of the advantages and disadvantages of the previous support joints, a new type of support joint was proposed. An experimental programme was proposed.(3)With the finite element method, calculated the parameters of supporting system such as stiffness, level spacing, excavating sequence, arrangement form and so on and drawed the laws of strength and deformation, the stability for excavation. The study also found that the integral stiffness, numbers, last support position, level spacing, arrangement form, erected time, excavating sequence, pre-stressed are more sensitive to the horizontal displacement. Integral stiffness, first support stiffness, first support position, numbers, level spacing, excavating sequence, pre-stressed are more sensitive to the top horizontal displacement. Integral stiffness, the level spacing, numbers, first support position, erected time, arrangement form, pre-stressed are more sensitive to internal force. Integral stiffness, numbers, level spacing, excavating sequence are more sensitive to the surface settlement.(4)Using previous laws, calculated and optimized parameters of supporting system in Yangsi deep excavation. The comparison of the calculation results with the monitoring data proved that the optimization method is feasible. Better economics and construction safety were achieved because of the optimization.