关键词: metro station, deep and large foundation pits, strip pit, circular pit, excavation sequences, numerical simulation

Abstract: For deep and large pits composed of different shapes, the excavation sequence significantly influences the deformation of the foundation pit and its supporting structures. To minimize the impact of different excavation sequences on construction stability and determine the optimal sequence, numerical simulations are conducted using finite element software based on the Fuzhou Metro Foochow Arsenal Station excavation project. Circular and rectangular sections are considered, and various excavation sequences are simulated. The following conclusions are drawn: (1) For smallspan pits, excavating the rectangular section first and then the circular section results in larger surface settlements compared to excavating the circular section first, whereas for circular and largespan pits, excavating the rectangular section first and then the circular section is more favorable. (2) Excavating the rectangular section first and then the circular section leads to smaller maximum horizontal displacements of the sidewalls compared to the reverse sequence. (3) For the circular section, cut and cover excavation is superior to open cut excavation, and preserving the core soil during excavation is the optimal method. In summary, excavating the rectangular section first and then the circular section, with the circular section excavated using cut and cover excavation while preserving the core soil, represents the optimal approach.