Prediction of jacking force in circular press-in caisson in clay

The press-in caisson method, renowned for its precise construction control, has gained extensive application in both terrestrial and marine engineering projects in recent years. Accurate control of the downward jacking force within an optimal range is essential for ensuring construction safety and efficiency. This study presents an upper-bound solution for the jacking force of circular caisson on the basis of streamline-based velocity fields under axisymmetric conditions. The proposed soil failure mechanism is validated through comprehensive finite element analysis. Extensive parametric studies have been conducted to investigate the influence of key factors on the jacking force factor ( N j ), including the cutting-edge angle, caisson roughness, caisson radius, penetration depth, excavation extent, and soil strength. On the basis of the analytical and numerical results, predictive equations for upper-bound solutions of the circular caisson jacking force are developed, with particular emphasis on their reliability across cutting-edge angles ranging from 25° to 50°. The proposed methodology is further validated through a field case study of an actual caisson engineering project. This research provides valuable insights into the fundamental mechanisms governing caisson jacking force and offers a practical analytical tool for the design and construction of caisson foundations.