Abstract: For deep and large pits composed of different shapes, the excavation sequence significantly influences the
deformation of the excavation and its supporting structures. To assess the impact of different excavation sequences
on construction stability and determine the optimal sequence, numerical simulations were conducted using finite
element software based on the Fuzhou Metro Chuanzheng Cultural City Station excavation project. Circular and
rectangular sections were considered, and various excavation sequences were simulated. The following conclusions
were 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, 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 cover excavation
while preserving the core soil, represents the optimal approach.

Key words: Metro station, Deep and large pits, Strip pits, Circular pits, Excavation sequences, Numerical
simulation