Optimization and Risk Assessment of Multi-Pit Excavation Strategies in Soft Soil Conditions

he stability of Diaphragm Walls (DWs) in deep foundation pits is a critical concern in urban construction, where complex excavation activities can induce significant structural deformations. This study aims to evaluate the impact of different excavation sequences on the displacement behavior of DWs to improve excavation safety and structural performance. A series of numerical simulations were conducted using four distinct excavation scenarios to analyze the lateral deformation patterns of DW1, DW2 and DW3. Based on the observed results, Case 3 demonstrated the most favorable performance, with wall displacements remaining within allowable limits, indicating improved structural stability. To further assess localized structural responses, the displacement behavior of DW4, DW5, DW6 and DW7 was also analyzed under Case 3. The results showed that all walls experienced inward displacement within allowable limits. The findings highlight that displacement magnitudes are influenced by factors such as wall position, excavation-induced stress redistribution, and soil-structure interaction. DW2, serving as a shared wall between adjacent pits, exhibited higher sensitivity to excavation activities. This study underscores the importance of optimized excavation sequencing and structural interaction analysis in mitigating wall displacements and enhancing the stability of deep foundation pits in complex urban environments.