Key technique for long and large-span deep foundation pits under complicated conditions using cover-cut method

The deep foundation pit by using the cover-cut method is widely applied in the construction of metro projects. This method has proved to be an economic and practical way. A case in Shenzhen Metro Line No. 5 is studied. The pit is 24 m deep, 722 m long, and under complicated conditions. The difficulties encountered in retaining structure, pit dewatering and structure construction during the construction process are studied. The summary based on the practice of key technique can be a reference for similar projects.