考虑系泊点深度的单点系泊系统锚桩水平承载性能理论分析

Theoretical analysis of horizontal bearing capacity of single-point mooring system anchor piles considering padeye depth

单点系泊系统因其克服恶劣海况的优越性成为我国海洋石油开发的重要系泊形式。然而,水下单点系泊系统锚桩-土体相互作用机制尚不清楚,尤其缺少考虑系泊点深度的水平承载性能计算方法。基于复合地基反力法,建立水平荷载下单点系泊系统锚桩的挠曲控制方程和边界条件,并编制相关计算程序;通过迭代法求解,获得不同系泊点位置下的锚桩荷载-位移曲线以及桩身位移、弯矩沿桩身的分布规律曲线;通过与数值模拟和既有离心模型试验结果的对比分析,验证了其准确性和可靠性;继而考虑系泊点深度对锚桩水平承载力的影响,进行参数分析,给出了最优系泊点深度取值范围。分析结果表明,增加系泊点深度可以显著减小锚桩的水平位移及弯矩最大值,从而提高锚桩的水平极限承载力。

Single-point mooring(SPM)system has been widely used in China’s offshore oil development due to its superiority in overcoming severe sea conditions.However,the research on the interaction mechanism between the anchor pile and soil in underwater single-point mooring systems remains inadequate,particularly with respect to the calculation method of horizontal bearing capacity that considers the depth of padeye depth.Utilizing the composite foundation reaction force method,the flexure control equation and boundary conditions of the anchor pile of the single-point mooring system under lateral load are established,and the calculation programs are compiled using iterative methods to obtain the anchor pile load-displacement curve and the distribution curve of pile displacement and bending moment along the pile shaft at different mooring point positions.The accuracy and reliability of results are validated through comparison with numerical simulation and existing centrifugal model test results.Furthermore,the parameter analysis is conducted to consider the impact of padeye depth on the horizontal bearing capacity of anchor piles and the reference range of the optimal padeye depth is provided.The findings indicate that increasing the padeye depth leads to a significant reduction in the lateral displacement and maximum bending moment of anchor piles,while also increasing the horizontal ultimate bearing capacity of the anchor pile.