邻近高铁线全套管灌注桩施工的微扰动分析

高速铁路对线路基础沉降要求极为严格，为确保高铁安全运营和结构安全，邻近高铁线桩基采用全套管灌注桩施工方法以减小对既有线的扰动影响。以宁和城际一期工程的板桥河段桩基工程为背景，基于PLAXIS 3D对钢套管施工过程进行模拟，并结合现场监测数据对邻近既有高铁线全套管灌注桩施工的微扰动进行分析。结果表明：土体侧向变形的模拟结果与实测结果总体吻合，但存在局部差异，采用套管逐节旋压并利用抓斗将管内部分土体取出的施工方法，对高铁桥墩周围土体的侧向变形影响较小；高铁桥墩处于钢套管施工影响范围内，其竖向和水平位移在钢套管施工期间存在一定变化，但均远小于预警值。

Analysis of Micro-disturbed Construction of Benoto Pile onAdjacent High-speed Railway Bridge

The limit condition of foundation settlement of high-speed railway line is strict. To ensure the operational safety of high-speedrailway and safety of structures near high-speed railway bridge, Beneto pile was conducted to mitigate the effect caused by pile construction. The pile foundation of Banqiao River of the first-stage project of Ninghe intercity railway inNanjing city was taken as the research object. This paper analyses micro-disturbed construction of Benoto pile near high-speed railway bridge by numerical simulation based on PLAXIS 3D and field measurement. The protective jacket tube was rotated and pressed by segment-to-segment approach and partial soil in the tubewas removed in time. Results show that the effect caused by this method is slight.With the increase of soil depth, the height of soil in the protective jacket tube should be increased either to avoid piping effect. The high-speed railway bridge pier within the scope of influence of Benoto pile construction. The verticaland horizontal displacements of pier much less than early warning value and fluctuate during the construction of the protective jacket tube. Results can provide reference for the design and construction of pile near high-speed railway bridge.