Experimental and Semitheoretical Analyses of Uplift Capacity of Belled Pile in Sand

Although belled piles have been widely applied to structures subjected to large horizontal loads, such as coastal structures, high chimneys, and transmission towers, their uplift capacity characteristics under various conditions have not been investigated in detail. In this study, model tests were performed in circular and half-circular chambers to determine the uplift capacity of belled piles in sandy ground under conditions such as relative density, penetration depth, and pile-tip inclination angle. Furthermore, image analysis was conducted by monitoring the model tests in a half-circular chamber to verify the shape of the failure surface. A semitheoretical model to predict the uplift capacity of belled piles in sandy ground was developed using the pile-tip failure angle and failure surface curve in accordance with the relative density, penetration depth, and pile-tip inclination angle based on the limit-equilibrium equation of a previous conventional pile. The values calculated using the proposed model were in good agreement with those obtained from experimental model tests.