Effect of Vertical Shaft Resistance on the Lateral Behavior of Large-Diameter Pile Foundation

Current research gradually recognizes that resisting moment M_s, induced by vertical shaft resistance developed on the passive side of pile shaft, has non-ignorable influence on the lateral bearing characterize of large-diameter pile embedded in stiff soil layers. This work firstly presents numerical solution for resisting moment which is suitable for any type of side friction models. Accordingly, a series of analytical expressions for resisting moment versus slope are established with hardening and softening τ-s curve models (i.e., shaft resistance). Furthermore, the comparison of case study indicates that the influence of shaft resisting moment cannot be ignored for large-diameter pile embedded in stiff soil material. Finally, parametric study is performed and results reveal that for hardening τ-s curve, resisting moment M_s will increase with increase of pile diameter, equivalent limit friction τ_u,eq and as decreasing critical displacement s_eu; for softening τ-s model, M_s will increase with increasing pile diameter, ratio of residual-critical displacement to peak displacement and ratio of residual shaft friction to maximum shaft friction.