杭州地铁既有线受新线近距离斜下穿影响的变形特点分析

Deformation Feature Analysis of the Effect of Closely Undercrossing Construction of a New Subway Line on Existing Subway Line in Hangzhou

地铁新线近距离斜下穿既有线路属于特级环境风险工程,虽然这方面已有一定的研究,但未见结合变化的施工参数等进行隧道动态变形的具体分析文献报道。杭州地铁4号线斜下穿既有1号线时,二者最小垂直净距仅2.1m,在软土地区无地层加固条件下对施工控制的要求非常高。分析了盾构下穿施工时既有1号线随施工参数而变化的变形特点,总结了一些规律,并给出了盾构下穿既有线路施工时的一些建议。

Closely undercrossing construction of a new subway line underneath an existing line belongs to high risk engineering projects. Though some existing studies are developed,there are few detailed analyses of the site conditions and varying construction parameters related to the observed behavior. The net vertical distance between the subway line 4 and the existing subway line 1 is only 2. 1meters for the undercrossing project in Hangzhou. The undercrossing is done without any ground improvement in soft soil area,thus it is critical for the displacement control in construction. The deformation features of subway line 1 are analyzed and some conclusions are drawn,and some suggestions are given for the undercrossing construction with considerations of specific soil and construction conditions.