A Prediction Method Based on Elasticity and Soil-Structure Interaction for Deep-Excavation Induced Deformations of Pile Foundations

Deep-excavations cause ground movements and, consequently, the deformations of the pile foundation of adjacent buildings. For deep foundations, the soil-pile-structure problem is influenced by both the greenfield soil movement due to excavation and the complex pile-soil, pile-soil-pile and pile-structure interactions. To estimate the greenfield soil displacements induced by the excavation, the superposition of ground losses relying on the virtual image technique is considered for both unsupported and braced deep excavation. Then, a two-stage continuum-based analysis method is used to evaluate the response of piles group (displacements and internal forces) considering a variety of superstructure configurations (i.e., a rigid cap, a stiff slab, and a stiff beam) or free head. Results will clarify the impact of the diaphragm wall support on both the soil movement and response of piles, quantifying the role of the superstructure stiffness on the foundation response. As shown, the presence of a different superstructure has a significant influence on the bending and axial distress of piles.