Optimization design and construction of large deep foundation pit groups in northwestern areas of China

There are more and more deep foundation pits in the northwestern areas of China, while the available references about the optimization design and construction of foundation groups are short. The comprehensive renovation project of Xining Railway Station covers excavations such as multi-layer basement, underground shopping mall, underground garage, underground tunnel and subway transfer station of high-rise buildings during the development of the current cities. Based on the large foundation pit groups, considering their characteristics, development progress, schedule and cost, the design principles of supports for the foundation pit groups are determined. According to the specific differences around the block, the optimization design of typical cross section of the supports and the dewatering scheme are proposed. The rationality of this scheme is validated by construction monitoring. Finally, according to the experiments on internal forces and construction tracking, the key points to control the construction quality of deep foundation pit groups are analyzed. It may provide reference for the design and control of similar support projects in the northwestern areas of China.