近距离管道基坑对运营地铁高架结构的影响

摘要:

超近距离基坑开挖通常会导致紧邻的地铁高架桥基础产生一定的变形,但目前超近距离市政管道基坑开挖对地铁高架桥影响的研究较少。针对天津地铁1号线某高架桥特别保护区内市政管道基坑展开工程实测,结合Plaxis3D有限元分析软件建立三维数值模型,对比分析了超近距离市政管道基坑对运营的地铁高架桥墩的影响,分析结果表明：在距离桥梁承台最近位置(距离1m)处,通过水泥土搅拌桩加固的措施,有效控制了基坑引起的水平变形,桥墩最大水平变形0.7mm,满足轨道交通结构允许位移量(20 mm)的要求。分析结果为以后相似工程的实施提供理论和实测参考和指导。

Abstract:

Excavation of ultra-short-distance foundation pits usually results in certain deformations of the adjacent subway viaduct foundation. However, there are few studies on the impact of ultra-short-distance municipal pipeline foundation pit excavation on subway viaducts. According to the actual measurement of the municipal pipeline foundation pit in a special protection area of a viaduct in Tianjin Metro Line 1, a three-dimensional numerical model was established in combination with the Plaxis3D finite element analysis software, and the impact of the ultra-short-distance municipal pipeline foundation pit on the operating subway viaduct pier was compared and analyzed. The analysis results show that at the closest position (distance 1m) to the bridge cap, the horizontal deformation caused by the foundation pit is effectively controlled by the cement-soil mixing pile reinforcement. The maximum horizontal deformation of the bridge pier is 0.7mm, which meets the allowable displacement of the rail transit structure (20 mm) requirements. The analysis results provide theoretical and practical reference and guidance for the implementation of similar projects in the future.