Construction Settlement Monitoring and Control Measures for Mining Method Tunnel Section by Cutting Piles Closely Under-passing Existing Metro Station

Abstract

Objective When the sectional tunnel closely under-passes the existing metro station by cutting piles, it has a significant impact on the deformation of the upper station. In order to ensure the safety of construction, it is necessary to take effective measures to control the settlement of metro station. Method Based on the project of a sectional tunnel under-passing the existing metro station, a three-dimensional numerical model is established to analyze the station settlement when being under-passed by cutting piles without settlement control measures. The settlement control effects with measures such as addition of temporary inverted arches, staggered excavation, and grouting reinforcement are studied. A multiple measure combination control scheme is proposed, and its feasibility is verified by the measured engineering data. Result & Conclusion The research results indicate that when the tunnel underpasses the station directly by cutting piles without taking settlement control measures, the maximum settlement of the station will exceed the specified limit. The grouting reinforcement produces the best effect on settlement control with the settlement being reduced by 57.3%. Addition of temporary inverted arches follows next by 40.4%, and staggered excavation has the least effect by 20.8%. The settlement limit can be met by using the multiple measure combination control scheme, which is verified to be feasible by the monitoring data, and can provide reference for similar projects.

Keywords

• metro tunnel
• under-passing
• numerical simulation
• metro station
• settlement monitoring