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大直径桩基在海洋工程中已越来越广泛应用。针对目前API规范p–y曲线对水平受荷大直径单桩的不适用性,通过离心模型试验研究了砂性土中大直径单桩分别在水平静力和循环荷载作用下的受力和变形特性。验证了通过实测桩身弯矩推算桩身变形和桩周土反力的有效性,分别获得了干砂和饱和砂的大直径单桩水平静力p–y曲线。在修正p–y曲线初始刚度的基础上,采用双曲线型p–y曲线分析了水平受荷大直径单桩的内力和变形。揭示了水平单向循环荷载下大直径单桩的桩身变形及内力变化特性,试验结果显示桩身变形和最大弯矩近似与循环次数的对数线性相关。最后,由各循环次数下的桩身弯矩获得了大直径单桩水平循环p–y曲线,提出了循环应力比相关的p–y曲线循环弱化因子,以及相应的桩基变形累积和内力变化分析方法。
Large diameter pile in offshore engineering has been more and more widely used. Aiming at the current unavailability of p-y curve of API specification to large-diameter single-pile subjected to horizontal loading, the stress and deformation of large-diameter single pile in sandy soil subjected to horizontal static and cyclic loads are studied by means of centrifugal model test characteristic. The validity of the pile deformation and the soil reaction on the pile is verified by measuring the bending moment of the pile body, and the p-y curve of the static pressure of the large diameter single pile of dry sand and saturated sand is obtained respectively. Based on the correction of the initial stiffness of the p-y curve, the hyperbolic p-y curve is used to analyze the internal forces and deformations of large diameter single piles. The characteristics of deformation and internal force of pile with large diameter under horizontal one-way cyclic loading are revealed. The experimental results show that the deformation of the pile and the approximate maximum moment are logarithmically linear with the logarithm of the number of cycles. Finally, the p-y curve of the horizontal circulation of single-pile with large diameter is obtained from the bending moments of the pile under each cycle, and the cyclic weakening factor of the p-y curve and the corresponding pile foundation deformation and internal force variation Analytical method.