Theoretical analysis of uplift bearing capacity of rock-socketed pile under cylindrical failure

The ultimate uplift capacity of rock-socketed piles is a critical parameter in the design of pile foundations for structures such as transmission towers and offshore floating platforms. A theoretical calculation model for the progressive development of uplift bearing capacity of rock-socketed piles in cylindrical failure mode is proposed. A bilinear model is employed to describe the pile-rock interface shear strength. Based on the principles of static limit equilibrium, analytical expressions for axial stress, axial relative displacement between pile and soil, and side friction resistance at different stages of pile units are established. The single-variable solver in Excel is employed to determine the elastoplastic interface depth z₀ at the pile-rock interface, thereby obtaining pile displacement and axial force distribution. The model demonstrates prediction errors of -8.1% and 6.1% when validated against ultimate uplift capacity measurements from both full-scale field tests of socketed single piles under uplift and scaled model tests documented in previous studies, demonstrating the validity of the proposed method.