Study On The Deformation Analysis And Control Technology Of Subway Shield Machine Underpassing The Bridge Pile Foundation Of High-speed Rail

With the rapid development of urbanization in China,the demand of high life quality makes a great number of people moving to the large cities.Accordingly,traffic jam problem is becoming more and more seriously.To solve this problem,intensive urban rail transit construction plays an important role in balancing the development of the region economy,improving the quality of people’s life,and enhancing economic benefits along the line.Of course,urban development under the shared economic circle is more dependent on the rapid construction of high-speed railways.Because of the extension of the old urban areas and the establishment of new urban centers,there is a widespread metro crossing-railway interval tunnels.In particular,for the 350km/h high-speed railway there are strict requirements for track regularity and settlement deformations.Certainly,it is very important to study how to ensure the security for the crossing of the subway tunnels through the existing high-speed rail lines.Based on the shield tunnel of Wuhan Metro Line 11 for Guanggu Railway Station to the Pharmaceutical Supervision Bureau Station underpassing the bridge pile foundation of the 350km/h high-speed rail,this paper selects the surrounding stratum,the bridge pier and foundation of the areas for the shield passing through the test section,the general protection area and the core protection area as the object,while using MIDAS/GTS finite element software,relying on numerical simulation results and construction monitoring data.This paper has made an overall analytical study on deformation caused by shield tunnel underpassing the bridge of the high-speed rail and the key techniques for reducing deformation.It marks the success of the research that the shield successfully crossed the core protected area of high-speed rail bridge in November 19,2016.The main results are as follows:(1)Reducing the impact of the shield tunneling on bridge structure is mainly to reduce the disturbance of the shield tunneling to the surrounding strata,which has a great relationship with the degree of the stratum deformation,rational selection of the shield parameters and the effective construction technology.Through reasonable selection of the shield tunneling parameters and the key construction technologies,the vertical and the horizontal deformation of the strata can be reduced,and the deformation of the bridge piles can be effectively reduced.(2)The monitoring data of the construction site and the results from the numerical simulation adopting MIDAS/GTS NX software are basically consistent under the different calculation conditions.Therefore,the numerical simulation methods and monitoring schemes are feasible.(3)Based on the research background of this paper,the shield tunneling parameters and attitude control of shield machine obtained through practice,as key construction technologies of "five steps",can ensure that the deformations of the deep soil and the bridge pier,as well as the deformation of the bridge meet the specification,which can provide guiding significance for similar projects in the future,especially for the similar projects in Wuhan.(4)When the shield tunnel underpassing the bridge pile foundation of the high-speed rail,it can effectively ensure the safety of the construction of shield tunnel and the deformation control of bridge pile foundation and meet the requirements by using the key construction technologies of "five steps",that is,Risk assessment→Deformation prediction → Test section optimization → Monitoring information feedback and adjustment→Post work evaluation.