Impact Analysis Of Foundation Pit Excavation On Deformation Of High-speed Railway Bridge Pier

With the continuous improvement of China's high-speed railway network,new projects and high-speed rail business lines are constantly crossing.Since the operation of high-speed rail requires extremely high safety and stability,in addition to maintaining the safety and stability of the project during the construction of the underpass project,the stability of the adjacent high-speed rail pier and superstructure must also be ensured.If the displacement of the high-speed railway bridge piers exceeds the control value,the operation safety of the highspeed railway will be endangered.In order to ensure the safety of high-speed rail,it is necessary to monitor the deformation of the construction of the underpass high-speed rail project and carry out a study on the deformation law.The thesis is based on the excavation of the foundation pit of Tongan East Road in Xiamen City underpass the Shixun Bridge project of the Hangzhou-Shenzhen Line.First,on the basis of on-site investigation,the engineering construction monitoring plan was compiled,and the on-site monitoring of the deformation of Shixun Bridge No.2 pier,No.3 pier,ground soil and supporting structure was carried out.Analyzing the monitoring data to get the deformation law.Then,the finite element analysis software was used to simulate the excavation process of the foundation pit of the water conveyance culvert,the simulated value and the measured value were compared and analyzed.The results showed that the monitoring data and the simulated data were consistent in deformation law,verified the correctness of the numerical simulation results and the rationality of the calculation model.Finally,by changing the form of the support structure,the effect of excavation of the foundation pit on the horizontal displacement of the adjacent high-speed railway bridge pier under different support types,different pile spacing,pile diameter and pile length is discussed.The supporting scheme with the best protection effect for the high-speed railway bridge pier and its pile foundation is proposed,which can provide reference for the design of supporting structure of similar projects.