新建市政立交施工对既有铁路路基稳定性影响分析

Analysis of the Impact of New Municipal Interchange Construction on the Stability of Existing Railway Subgrade

为研究新建市政立交邻近铁路施工对既有铁路路基稳定性的影响规律,以S43呼和浩特机场高速公路什不更互通工程为例,对邻近铁路桩基开挖过程中的基坑支护结构位移、周围地表沉降、铁路路基沉降等通过有限元模拟进行了系统分析。结果表明:支护结构产生的最大水平位移为3.6 mm,距离支护结构5.34 m位置处的地表沉降量最大,其值为5.6 mm;新建市政立交施工引发的铁路路基最大累计变形均发生在靠近主线主墩位置附近,竖向沉降最大值为-3.07 mm,各测点的最大变形量均小于路基变形预警值。基坑支护结构强度较大时会使既有铁路路基发生轻微隆起,但随着支护结构的拆除,基坑周围土体向内部卸荷,路基仍以沉降为主。研究成果可为同类工程的施工提供参考。

In order to reveal the impact of the construction of new municipal interchange adjacent to railways on the stability of existing railway subgrade,a systematic analysis was conducted through finite element simulation of the displacement of the foundation pit support structure,surrounding surface settlement,and railway subgrade settlement during the excavation process of the adjacent railway pile foundation,taking the S43 Hohhot Airport Expressway Shibu Geng Interchange Project as an example.The main conclusions are as follows:the maximum horizontal displacement produced by the support structure is 3.6 mm.The maximum surface settlement is 5.6 mm,occurs at a distance of 5.34 m from the support structure.The maximum cumulative deformation of the railway subgrade caused by the construction of new municipal interchange occurs near the main pier of the main line,with a maximum vertical settlement of-3.07 mm.The maximum deformation at each measuring point is less than the subgrade settlement warning value.When the strength of the foundation pit support structure is high,it will cause slight uplift of the existing railway subgrade.However,with the removal of the support structure,the soil around the foundation pit will be unloaded internally,and the subgrade will still be mainly settled.The research results can provide reference for the construction of adjacent existing railways in other municipal interchange projects.