原位保护条件下捷运系统的改扩建基坑方案研究

Research on the foundation pit scheme of rapid transit system reconstruction and extension under in-situ protection

某机场三期空侧捷运系统需要进行改扩建,工程施工期间应保障既有捷运功能的正常运营,同时建设场地存在深厚承压水层,给基坑实施带来巨大挑战。工程实施总体方案采用“倒边施工+弹钢琴+悬挂式止水”的方式,科学划分基坑分区和施工工序,合理选用基坑围护结构,结合悬挂式降水方案,并采用数值分析验证合理,确保了既有捷运系统的运营安全。

The third-phase empty side rapid transit system of an airport needs to be rebuilt and expanded.During the construction period,the normal operation of the existing rapid transit functions should be ensured.Meanwhile,the deep confined water layer exists in the construction site,which brings great challenges to the implementation of foundation pit.The overall project implementation plan adopts the method of“inverted edge construction+piano+hanging water stop”,scientifically divides the partition of foundation pit and the construction process,reasonably chooses the foundation pit retaining structure,combines with the hanging dewatering scheme,and verifies the rationality by numerical analysis,thus ensuring the operation requirements of the existing rapid transportation system.