Abstract:Complex geological conditions and surrounding environment will restrict the construction progress to a large extent. Taking the construction of deep foundation pit for 70# pier of Nanyanjiang Intercity Railway Bridge across Qinhuai River as an example, the method of locking steel pipe cofferdam + section steel internal support is adopted. The practice proves that this method is stable and reliable with the good water stopping, good recovery and good economy. Some experience is accumulated for the excavation and support construction of deep foundation pit for large-sized buildings, and some references are provided for the similar projects in the future.