Large-diameter single piles for wind turbines are mainly used to withstand the horizontal loads caused by wind, waves and current. To maintain the normal operation of the wind turbines, only a rotation of 0.25°. is allowed at ground level. Such a strict requirement has caused numerous researches on load-transfer curves (p-y curve) to more accurately analyze the nonlinear lateral response of piles. Due to the presence of blades, the horizontal loads are not entirely imposed on the centreline of the structures. Eccentric horizontal loads would cause the torsion of the piles and extra soil strains, thus resulting in a reduction in the horizontal resistance. Therefore, an attempt will be made in the present study to investigate the effect of the eccentricity on the lateral response by constructing a kinematically admissible continuous velocity field of coupled torsion and lateral movement of a planestrain circular pile. Through the velocity field, the relationship between the limit lateral load and the eccentricity is presented. Also, combining the mobilizable strength design method, the effect of the eccentricity on the p-y curve is examined and a simplified design chart is then proposed.
Jian Yu, Maosong Huang, Kanmin Shen and Chenrong Zhang
Keywords: p-y curve, lateral load, upper bound, eccentric load
Publisher: DFI