A Case History of the Excavation of Deep Foundation Pit Adjacent to Railway

Minzhi station foundation pit in Shenzhen subway is adjacent to Pingnan railway. There is obvious unsymmetrical loading above the pit, and the pit is affected by the dynamic load from train. Therefore, the impact of pit excavation on the railway and the safety of the pit itself must be paid close attention to. The main technical measures adopted in the design and construction of deep foundation pit adjacent to railway is introduced. The measures include using steel pipe piles and prestressed anchor cables to reinforce the railway embankment, using diaphragm wall in the building envelope, setting strand prestressed cables in the middle of the diaphragm wall, using sleeve valve pipe grouting to reinforce the soil, and so on. The settlement of the railway embankment and track, as well as the horizontal displacement of the diaphragm wall, is monitored. Monitoring results show that these technical measures can ensure the normal operation of the railway and the safety of the pit itself.