The impact of large-scale foundation pit group excavation on existing urban rail transit interval tunnels and safety risk control technology

Abstract

At present, the foundation pit construction is developing towards the trend of “deep and large”, the excavation range is large, and precipitation measures are usually required, and the impact of foundation pit excavation on adjacent buildings(structures) has attracted increasing attention. The impact of large-scale foundation pit group excavation on the existing urban rail transit interval tunnels and the safety risk control technology are studied through literature research and numerical simulation. Firstly, the deformation characteristics and influencing factors of large-scale foundation pit group excavation are analyzed, and the relevant cases and experiences in the existing literature are summarized. Secondly, the possible safety risks of foundation pit excavation are discussed, the deformation of foundation pit excavation on the existing urban rail transit section tunnel is calculated through numerical simulation, and the risk control technology and measures in the form of underground diaphragm wall + internal support support structure are proposed to meet the requirements of the specification. The result show that the excavation of foundation pit group has a certain impact on the existing urban rail transit section tunnels, but the potential risks can be reduced and the safety of the tunnel structure can be guaranteed through reasonable safety risk control technology. The result of the study provide a reference for the safety design and construction of the project to be built.

Keywords

large foundation pit groups / excavation impacts / urban rail transit / interval tunnels / security risk control technology