Multi-Method Sensitivity Analysis of Influencing Factors on the Lateral Displacement of Retaining Piles in Asymmetric Excavations in Soft Soil Areas

Asymmetric structures are widespread in deep excavation engineering and place heightened demands on the deformation control and safety of retaining systems. This study focuses on an asymmetric deep foundation pit project in a soft soil area, using PLAXIS 3D to model the entire excavation process, with model accuracy confirmed by measured values. The study systematically explores the impact of multiple factors—including surcharge loading, external groundwater level, soil internal friction angle and cohesion, and the elastic modulus and embedment ratio of the retaining structure—on the lateral displacement of retaining piles. Orthogonal experimental design is utilized to calculate lateral displacements for various factor combinations, with sensitivity analyzed using the range method and verified by grey relational analysis. The results demonstrate that all factors influence the maximum lateral displacement of retaining piles to varying degrees. Both the orthogonal tests and range analysis consistently identify the influence ranking as soil internal friction angle > soil cohesion > retaining structure elastic modulus > embedment ratio > external groundwater level > surcharge loading. The grey relational analysis yields identical rankings. These results offer theoretical support and practical guidance for the design and monitoring of retaining structures in asymmetric deep excavations within soft soil environments.