Influence Analysis of Newly-built Channel Foundation Pit Under-passing High-Speed Railway Bridge on Adjacent Piers

Abstract

[Objective] When a new channel foundation pit under-passes a high-speed railway bridge, the excavation and unloading of the foundation pit will cause the displacement of the soil surrounding the bridge, and further affect the high-speed railway bridge. In order to ensure the operation safety of the high-speed railway line, it is necessary to analyze the influence of the foundation pit under-passing the bridge on the adjacent piers. [Method] With the project of the new channel foundation pit of Beijing-Hangzhou Grand Canal under-passing the Shanghai-Kunming High-speed Railway bridge as the background, based on finite element simulation and on-site measurement, the influence of foundation pit construction on the existing high-speed railway piers is analyzed. The feasibility and effect of the scheme adopting multiple rows of bored piles+inclined brace reinforcement for the foundation pit construction are evaluated. [Result & Conclusion] As the channel foundation pit construction causes horizontal displacement of the high-speed railway piers along the bridge, it is proposed to take proper measures to increase the stiffness along the bridge. The closer the bored pile is to the high-speed railway pier, the larger the horizontal displacement. With the construction of the channel foundation pit, the horizontal displacement of the bored pile shows the trend of increasing first and then decreasing. The displacement of piers under the reinforcement scheme of multiple rows of bored piles + inclined brace is less than the 2mm limit required by the relevant standard, meeting the requirements for train operation safety.

Keywords

• high-speed railway bridge
• channel excavation
• pier displacement
• reinforcement of foundation pit