高压电缆下穿轨道交通地面线变形监测

Monitoring Deformation of Existing Ground Track of Urban Rail Transit Caused by Under-passing of High-tension Cable Pipeline

研究目的:大直径管线下穿既有轨道交通地面线为重大风险工程,为保证工程顺利施工和既有线路安全运营,应进行严格的变形监测。本文阐述管线下穿对既有地面线路基、轨道的变形影响及监测,为类似地面线下穿工程提供借鉴。研究结论:受施工影响,既有地面线路基变形基本经历了下穿明显沉降、工后显著沉降、沉降趋缓、沉降稳定的过程,路基沉降量较大,轨道轨顶沉降相应增加,应进行必要的调轨抬升;轨道几何形位变形和线路钢轨位移均较小,未超过控制值;受下穿侧土体扰动和地下水位季节性变化的影响,上地桥出现接近施工侧结构上浮现象,桥与路基间差异沉降增大,类似工程应注意回填土和地下水对桥体的异常影响。

Research purposes： The project of large diameter under-passing the existing ground track of urban rail transit faces the large engineering risks.The strict monitoring should be conducted to the existing ground track in order to guarantee the engineering going on smoothly and the traffic safety of the existing track.This paper mainly introduces monitoring the deformation of the existing ground track caused by the under-passing of pipelines for providing the reference to the similar works.Research conclusions：Affected by the under-passing of the pipelines,the roadbed of the existing track experienced the process of apparent settlement during construction,apparent post-construction settlement,settlement becoming slow and settlement becoming stable.As the roadbed settlement was large and the rail settlement increased relatively,the rail was uplifted necessarily.The track geometric deformation and rail displacement were small and didn＇t exceed the control values.Affected by soil disturbances and the seasonal change of the groundwater level,the structure of Shangdi Bridge near the engineering site floated and the differential settlement between the Bridge and the roadbed increased.The attention would be paid to the influence of the backfill soil and groundwater on the bridge.