Numerical analysis on the mechanical response of grouted connection for pile-bucket foundation

Abstract

As a new foundation type for offshore wind turbine (OWT), pile-bucket foundation, which consists of a monopile and a bucket foundation, has good prospect in engineering application and has received wide attention. However, most of the current research ignored the function of grouted connection (GC) and assumed that the pile and bucket were rigidly connected, which may lead to unrealistic estimation of the loading response of pile-bucket foundation. In this study, Finite Element Analysis (FEA) is conducted to study the influence of grout connection on the bearing characteristics of pile-bucket foundation, with a special focus on the mechanical response of the grout connection itself. The concrete damage plasticity (CDP) model is used to simulate the mechanical response of the grout material. After validation of the numerical model, twelve simulations are conducted by changing the grout thickness, grout length and stiffener arrangements. Though the variance of grout thickness and grout length has little impact on the load-displacement curves of the pile-bucket foundation, the optimal grout thickness and grout length could be determined according to the development of contact pressure, stress and damage of the grout connection. On the other hand, the employment of stiffener leads to notable stress concentration and fluctuation, however, it also improves the overall capacity of the pile-bucket foundation and effectively controls the damage of the grouted connection. The numerical result is expected to provide some reference value for the structural design of grouted connection for pile-bucket foundation.