Study on the Key Technology of Marshland Foundation Pit Construction

The foundation pit of the Juzizhou Island Station is a representative urban rail transit project which has the largest excavation depth. In the foundation pit area, geological and hydrological conditions are very complicated, the sand pebbles and slate strata are thick, groundwater is connected to Xiangjiang river, the underground water level is high, and the station is next to the Juzizhou Island-Xiangjiang bridge, which have brought many problems to the construction of this station. Based on the Juzizhou Island Station foundation pit project, this paper introduces the key technologies such as grouting water plugging in high water pressure area, the construction of diaphragm wall in upper-soft and lower-hard ground and the safety control technology of blasting excavation of foundation pit slate. Based on the monitoring results, the safety of key technologies is verified, which can provide reference and guidance for similar engineering construction.