摘要
Abstract
To address the challenges posed by a municipal road deep foundation pit in water-rich silty sand strata,e.g.adjacent to a subway,with great excavation depth and an ultra-long linear layout,this study investigated three key technologies:layered and segmented excavation,coordinated support construction,and comprehensive groundwater management.The project adopted an excavation method characterized by"vertical layering,longitudinal segmentation,bracing before excavation,and time-limited enclosure,"to establish a combined support system of concrete and ϕ609 steel struts.Full-cycle groundwater control was achieved through the measures,such as pre-dewatering,targeted dewatering,and excavation-phase drainage and cutoff.Practice has shown that the technical system effectively controls foundation pit deformation,ground surface settlement,and seepage risks,ensuring the safety of both the foundation pit and adjacent structures.The maximum horizontal displacement at pile heads is 25.0 mm,the maximum ground surface settlement is 19.0 mm,the settlement of the adjacent subway structure does not exceed 1.2 mm.This approach provides a valuable reference for similar projects.关键词
富水粉砂/紧邻地铁/深基坑/时空效应/协同施工/降水止水/综合治理/安全性Key words
water-rich silty sand/adjacent to subway/deep foundation pit/spatiotemporal effect/coordinated construction/dewatering and cutoff/comprehensive management/safety分类
交通工程
