Bearing-deformation characteristics of the tetrapod piled jacket foundation under combined wind and wave cyclic loading

Abstract:

To accurately evaluate the bearing and deformation characteristics of a four-pile jacket foundation under complex environmental loads, a three-dimensional numerical model was developed based on the improved nonlinear hysteretic p(soil resistance) -y (lateral displacement of the pile) curve, with P-multipliers incorporated to account for pile-group effects and axial forces. Furthermore, a two-point combined cyclic loading approach was adopted to represent wind and wave loads, respectively, taking into consideration differences in load amplitude, frequency, and application height. Results indicate that when the pile spacing is ≥7D, the group pile effect can be negligible, and as the loading height increases (constant loading displacement), the influence of axial forces on the foundation’s lateral behaviors is strengthened. An increase in the wave load ratio and a decrease in the wind load height significantly amplify the deformation and bending moment of the foundation, and it is more sensitive to variations in the load ratio. Under small-amplitude cyclic loading, the pile head displacement increases linearly with the cycle number (in logarithmic coordinates), and the cumulative displacement tends to stabilize. However, at a loading amplitude of 0.4, the plastic cumulative displacement continues to increase.