Study on the weakening of soil-structure interaction under long-term lateral load for monopile-supported offshore turbines

Abstract

The monopile-supported offshore wind turbines are located in a complex marine environment, bearing various long-term cyclic loads such as wind loads, waves, and currents. To explore the weakening of soil-structure interaction under long-term lateral load for the pile foundation, a series of model tests were conducted in the laboratory under normal gravity conditions, and the evolving trends for the weakening coefficients of varying soil depths and pile diameters were analyzed, leading to the proposal of a new expression for the weakening coefficient considering the governing factors in soil-structure interaction. The new formula for the weakening coefficient proposed in this paper is validated through the experimental results of this study and other references. Through a numerical example, affirming the viability of the soil stiffness attenuation model based on the finite element analysis method and revealing the weakening law of foundations for different cycling processes. This research contributes valuable insights for designing and analyzing offshore turbine foundations, particularly in the context of weakening phenomena.