Research Of Foundation Displacement Influence On Adjacent High-speed Railway In Service Caused By New Bridge Construction

In recent years,with the acceleration of infrastructure construction in our country,the traffic network is becoming increasingly intensive and crossings often occur.When the new bridge is under construction,it will inevitably disturb the soil.The soil deformation will generate additional load on the adjacent high-speed railway bridge foundation and cause secondary foundation displacement.The high smoothness of high-speed railway requires that the disturbance to the soil should be minimized during the construction of the new bridge so that the foundation displacement of the high-speed rail is controlled at a reasonable limit.Zhao Kanzi ramp bridge passes between the 438 and 439 piers of Harbin-Dalian passenger dedicated line,and the construction and operation load both have influence on the foundation displacement of high-speed railway bridge.First of all,Flac^3D5.0 software was used to simulate the construction project and calculate the foundation displacement of high-speed railway bridge.By comprehensively considering the deformation requirements of the relevant codes,the deformation limits,warning values and prevention values were determined and used to evaluate the foundation displacement of high-speed railway bridges.In addition,the deformation trend of high-speed cap with the process was analyzed.The deformation of high-speed railway pile group along pile depth was studied.The deformation of corner pile,side pile and central pile was compared.Secondly,in order to analyze the influence of various factors on the deformation of the cap,based on the original scheme,single factor experiments were designed with the following distance between the new pile and the existing group pile,the length of the new pile and the construction sequence as variables.In order to explore the significance of the various factors on the results,four-factor and four-level orthogonal test was designed.Finally,two factors that have significant effects on the foundation displacement were selected for a two-factor and four-level orthogonal test.The division of affected area was based on the deformation control standard and the area was divided by the method of drawing contour lines.If the foundation displacement is less than the prevention value,this area is considered as non-affected area where no further measure is required.If the displacement is less than the alert value,this area is considered as less affected area where deformation monitoring should be performed.If the displacement is less than the limit,this area is considered as strong impact area,where the monitoring and contingency plans should be strengthened.If the displacement exceeds the limit,this area is considered as severely affected area that affects the normal operation of the track,where the renovation measures should be taken.