Abstract: The excavation of deep foundation pits has become increasingly common in urban development, and their influence on adjacent structures has emerged as a critical concern. Focusing on a deep excavation support project in Shenzhen located near an existing basement structure, a three-dimensional numerical model was established using finite-element analysis software to evaluate the impact of excavation on the adjacent basement. The study shows that as the support system deforms progressively during excavation, the nearby basement undergoes corresponding horizontal deformation and vertical deformation. Deformation reaches its maximum when the excavation reaches the final depth, with peak values occurring along the basement sidewall closest to the pit. Analytical results indicate that the deformation induced by this excavation remains within acceptable control limits. To further ensure deformation control, it is recommended to increase the stiffness of the support system in the central sections or enhance the mechanical properties of the surrounding soil. During construction, strict quality control, enhanced monitoring, and adaptive construction management are essential to maintain the safety of the adjacent basement.

Key words: Deep Excavation, Finite Element Simulation, Adjacent Impact Analysis