| With the rapid development of the national economy and the transportation industry,high-speed railways keep extending and the new lines are becoming denser and denser,so more and more projects which are parallel to high-speed rail or constructed under the high-speed rail emerge.In order to ensure the smoothness of high-speed rail and operational safety,high-speed railway must maintain a high stability,so the requirements for controlling high-speed rail displacement is very strict.If the displacement is too large,it will affect the normal operation of high-speed rail,so it is very necessary to analyze the impact of tunnel to its adjacent high-speed rail.At present,there are not many precedents for the construction of underwater tunnel in parallel with high-speed rail at home and abroad.The analysis of the impact on high-speed rail generally refers to impact of foundation pit on its adjacent high-speed rail and impact of tunnel on its upper high-speed rail.Therefore,this paper relies on the construction of underwater open-cut tunnel in parallel with Beijing-Shanghai high-speed rail,space between tunnel and high-speed rail,dewatering and excavation procedure of tunnel are analyzed to research the impact on its adjacent high-speed rail.Firstly,the calculation method of horizontal and vertical displacement of adjacent high-speed railway pile foundation is introduced.Through the two-stage analysis method,the deformation of the lateral soil caused by the excavation of the open-cut tunnel is obtained,and the deformation of the soil is used to analyzed the deformation of pile foundation.The interaction between the soil and the pile foundation is deduced.In this paper,the displacement calculation method of pile foundation in different layered soils is analyzed,and the relationship between displacement of single pile and pile group is studied.Secondly,the finite difference numerical simulation software is used to establish the numerical model of the excavation tunnel and the high-speed railway.The change of displacement of the high-speed railway caused by the tunnel excavation under the different distance between the tunnel and the high-speed rail is analyzed,and the displacement of the high-speed railway pile foundation and pier are studied.According to the deformation limit of high-speed rail,the tunnel and high-speed rail reasonable and feasible spacing is deduced.The results show that the normal operation of high-speed rail is not subject to interference when the spacing is above 50m,it could not guarantee the safety of high-speed rail when the spacing under above 30m.It’s necessary to consider spacing between tunnel and high-speed railway during the design and construction of tunnel to reduce the impact of tunnel on high-speed rail.Then,according to the construction of underwater tunnel,the influence of tunnel dewatering on the adjacent high-speed rail is discussed.By simulating the different dewatering conditions,the effects of different dewatering rates on the tunnel and the high-speed rail are analyzed.Under the three kinds of dewatering conditions,the displacement and pore pressure of tunnel and adjacent high-speed are analyze.The simulation result shows that dewatering in more stages can reduce the influence of dewatering on high-speed rail.The displacement response law of pile foundation of high-speed rail and its piers are simulated and analyzed.For different stages of tunnel excavation and support,the deformation of the adjacent high-speed rail caused by the loss of the soil is studied by numerical simulation,and the result is compared with the displacement limit of the high-speed pier.The displacement change in each excavation process is also studied.The analysis result shows that the displacement of the high-speed rail pier in the first four excavation stages is 70%of the total displacement.Finally,the control measures of the high-speed rail structure are taken to minimize the interference caused by the construction to the high-speed rail,and the comparison between the construction condition and the monitoring results shows that the safety control measures play a positive role in reducing displacement of the high-speed rail.It can provide reference to similar engineering. |
