Modified p-y Curves Method Based on Degradation Stiffness Model of Sand

Abstract

Most of the existing p-y curves are based on the model test results of small-diameter pile under cyclic loading of finite times, which makes it difficult to accurately describe the displacement accumulation of large-diameter pile under long-term horizontal cyclic loading and the cyclic weakening characteristics of soil. Therefore, based on the subroutine provided by Abaqus, a stiffness degradation model of the pile-soil system considering the long-term cyclic weakening effect of sand was established, and the p-y curves of large-diameter pile were obtained based on numerical analysis. Then, by introducing the concept of cyclic reaction ratio, the stiffness degradation factor of the pile-soil system was obtained, and the initial foundation reaction modulus was modified as well. Finally, a modified p-y curves method based on the degradation stiffness model of sand was proposed. By comparing with the test results, the validity of this method is verified. This modified p-y curves method, which is able to consider the effects of loading characteristics, number of cycles, cyclic weakening of sand stiffness, provides a concise and effective analysis method for the preliminary design of monopile foundation under long-term horizontal cyclic loading.

Keywords

• sand
• monopile
• degradation stiffness model
• scale effect
• cyclic loading
• p-y curves