Construction Risk Analysis Of Viaduct Over Crossing Intercity Railway Underground Station

With the development of China's urbanization process,the conflicts between rapid increment of traffic demand and limited urban space are becoming sharper.Therefore,it is an inevitable choice to make full development and utilization of overground and underground space.Due to the design limitations of transport line,overground and underground architecture at the same places may occur cross,parallel and overlap.How to make sure the safety and stability of that is both the research hotspot and technical challenge faced by engineers.Based on a project that express way viaduct which was under construction over crossing intercity railway underground station,the risk on station and surrounding environment during viaduct construction had been studied,using the method of site survey,numerical analysis and risk assessment.The main work and research results are as follows:(1)The laws and regulations,specialized codes and project cases which were similar and suitable for this project were investigated to confirm the safety control standard about force and displacement of intercity railway underground station.(2)Three dimensional numerical models considering the relative position were established,to analysis the force and deformation of underground station,track slab and overlying strata settlement,under the conditions of different construction steps(pile foundation,pile caps,bent caps and superstructure)and different span.(3)The R = P ×C method was adopted,combined with field investigation data,expert inquiry and numerical analysis results,the construction risk about viaduct itself and that effect on over crossing intercity railway underground station,had been assessed,and then a reasonable risk grade was obtained.(4)Based on the risk grade mentioned above,the risk control measures against specific risk and emergency treatment for unexpected accidents had been given.