Study On The Interaction Between Bridge Pile Foundation Construction And Adjacent High-speed Rail Operation

In recent years,with the continuous development of China's economic,high-speed rail network and expressway network have been continuously developed and expanded.There must be many intersecting lines,and there will be mutual influence between the bridge construction and the crossing railway operation.Starting from pile foundation construction in bridge construction,this paper focuses on the interaction between bored pile construction of pile foundation construction and high-speed rail operation.This article relies on the TJ25 section project of Yinghong super bridge which crosses the Wuhan-Guangzhou High-speed Railway and is built by fifth construction Co,LTD of CTCE group.Through the field test,finite element numerical simulation and data analysis,the relevant construction of the bridge pile foundation and the high-speed rail operation are mutually carried out.The concrete research work and achievements are as follows:Firstly,divide the site into three reasonable areas,and place test points in each area to test the vibration acceleration time-history curve.Analyze the change rule of the acceleration peak along with the high-speed rail lines,the frequency distribution of different test positions and the blocking effect of the rotary jet pile on the vibration wave.The study shows that the peak value of the vibration acceleration time history curve measured near the pile foundation is only 1/10000 of the gravity acceleration.In one part,it can be considered that the impact of the vibration wave propagation caused by high-speed rail operation on the pile foundation is very limited.Secondly,through on-the-spot concrete test,it is investigated whether the vibration generated during passing of the high-speed rail has an effect on the strength of cast-in-place concrete at the construction site of the pile foundation,the influence of concrete forming at different locations from the source and affected by the vibration time.The study shows that the vibration of high-speed rail can improve the strength of early concrete,especially for concrete in the initial setting period,but it has little effect on the concrete after final molding.Finally,Midas GTS finite element software is used to study the influence of pilefoundation construction vibration on the operation of high-speed railways.By using the control variable method,the impact of the impact loads on the internal force of the high-speed rail bridge is studied at different depth,different weight,different stroke and different position.The displacement and the maximum peak velocity of the vibration are compared with the limit values in the standard.It is found that the results obtained do not exceed the allowable conservative limit,so it will not have an adverse impact on the safety of high-speed railway bridge and operation;through simulation analysis of the influence of displacement,it can be seen that the impact generated by the piling distance of 5m or less is not enough to affect the displacement of the high-speed rail girder.The analysis of the effect of vibration velocity shows that the conservative vibration speed limit is 1cm/s,the construction distance is 10 m for the safety.