Influence And Reinforcement Of Tunnel Excavation Construction On Pile Foundation Of Adjacent Bridge

Because of the current urban traffic pressure is too large,in order to alleviate this situation,many cities are planning to build a convenient subway.When building a subway tunnel,there are many overground buildings and municipal roads.The use of shallow buried excavation method will have a great impact on the ground deformation and adjacent pile foundation,especially after the selection of inappropriate construction methods and existing structural reinforcement measures,which will form a large safety hazard to the engineering.therefore,for the underground tunnel under the existing bridge pile foundation engineering,research and design of various construction scheme and reinforcement scheme has a very important practical value for the existing bridge foundation deformation and force.The research background of this paper is the construction of Wear bridge in dongguan-Huizhou inter-city tunnel.firstly,this paper studies the theory,and then carries on the simulation on the basis of the research.the results can be summarized mainly including the following points.Through theoretical analysis and simulation experiment of tunnel crossing project,the general rules of local formation change are mastered.The simulation results show that the underlying deformation is the main factor causing the deformation of the adjacent bridge pile foundation during the construction of the shallow buried excavation tunnel.At the same time,according to the spatial location relationship of existing pile foundation and tunnel,the pile foundation within the influence line of tunnel excavation is classified and treated.Through the combination of the specific characteristics of Technolab bridge under the dongguan-huizhou section tunnel of dongguan-Huizhou intercity railway,the 3d model was established by the software MIDAS-GTS,and the internal law of the deformation caused by the construction of the pile foundation and the ground was further explored,and then the most reasonable construction scheme was established.After determining the construction method,study the influence law of different excavation footage on existing pile foundation and surface deformation,and study the stress situation of tunnel lining structure,finally from the economic and safety aspects,select the most appropriate excavation footage.This paper mainly summarizes the main measures to control the settlement of existing pile foundation and differential settlement between piles: isolation method,grouting reinforcement method and underpinning method,and emphatically studies the concrete operation method of grouting reinforcement method in high construction project.After determining the reasonable excavation method and the appropriate excavation footage,the influence of different grouting scope around the pile foundation on the deformation of the pile foundation is simulated and simulated,and the law is analyzed.through the consideration of the safety factors and economic factors in the actual construction of various reinforcement schemes,the appropriate grouting scheme is finally selected.Based on the analysis of the site conditions of Technolab Establishment bridge under the condition of the shack-pine section tunnel in dongguan-Huizhou intercity railway,combined with the construction experience of the shallow buried excavation method,this paper analyzes and studies the problems that may occur in the design and actual construction of existing bridge pile foundation grouting reinforcement and tunnel excavation,and determines the key points of the design construction.