新建地铁下穿既有城铁地铁同台换乘站改技术研究

新建成都地铁6号线下穿既有地铁2号线与成灌城际铁路同台换乘的犀浦站,为实现三线换乘,需要对犀浦站进行改造。本文分析了该站改工程的重难点,优化了站改方案,阐述了既有站房立柱的桩基托换技术;且在桩基托换和基坑开挖过程中,监测了周边地下水位、托换站房立柱及城铁桥墩的沉降。实践表明:通过优化换乘通道基坑开挖深度,可以做到城铁桥墩周边不降水,且桩基承载力满足要求;采用叠合梁被动托换技术对站房立柱进行托换,解决了新建换乘通道与既有站房立柱在空间上的冲突;这可为类似工程设计、施工提供参考。

Technology Research of Newly-built Subway Passing Beneath the Existing Subway with the Same Platform Transfer Station

The newly-built Chengdu Metro Line 6 crosses beneath the existing Metro Line 2 and Chengguan Intercity Railway interchange at Xipu Station,in order to realize the three-line interchange,the Xipu Station should be retrofitted.This paper analyzed the station change project difficulties,optimized the station change program,described the pile foundation replacement technology for existing station columns;and in the pile foundation replacement and foundation pit excavation process,monitoring was performed on the surrounding groundwater level,replacement station column and the settlement of the urban railway piers.Practice shows that:by optimizing the depth of excavation for the transfer channel,it is possible to achieve no precipitation and the pile bearing capacity meets the requirements of the pier;the stacked beam technology is adopted for the replacement of the station house columns,which solves the spatial conflict between the newlybuilt transfer channel and the existing station house columns.The results can provide reference for the design and construction of similar projects.