水下管汇吸力桩竖向极限承载力研究

Research on Vertical Ultimate Bearing Capacity of Suction Pile of Subsea Manifold

吸力桩是海洋油气资源开发工程中水下管汇设施常用基础形式之一。为明确竖向载荷作用下吸力桩周围土体的影响范围及解决吸力桩的竖向承载力计算问题,采用理论公式计算和有限元仿真两种方法对极限承载力进行求解,采用数值软件建立了数值分析模型,利用位移控制方法,得到了吸力桩的载荷-位移曲线,并得出吸力桩的竖向承载力约为7 000 kN,规范公式计算得吸力桩竖向极限承载力为6 582. 4 kN,并与数值分析结果进行对比,结果显示,有限元分析求得的吸力桩竖向承载力与理论公式计算结果偏差为6. 34%。通过分析吸力桩周土体的屈服过程,发现在加载初期,屈服主要出现在桩端土体,随后桩端屈服区不断扩展,顶部土体开始出现屈服,并逐渐向下扩展,最终整个屈服区完全贯通。研究结果可为吸力桩竖向极限承载力分析提供技术参考,对吸力桩的稳定性和安全性评估具有一定的指导意义。

To understand the influenced range of the soil around the suction pile under the vertical load and address the calculation problem of the vertical bearing capacity of the suction pile,theoretical formula calculation and finite element simulation are used to solve the ultimate bearing capacity.The load-displacement curve of the suction pile is obtained.The vertical bearing capacity of the suction pile is about 7000 kN,the vertical ultimate bearing capacity of the suction pile is 6582.4 kN.Compared with the numerical analysis results,the vertical suction pile obtained by the theoretical formula has a deviation of 6.34%.Through the analysis of the yield process of the soil around the suction pile,it is found that in the initial loading,the yield mainly appears in the soil at the end of the pile.Then the yield zone at the end of the pile continues to expand.The top soil begins to yield,and gradually expands downward.And finally,the entire yield zone completely connected.The study can provide technical references for the analysis of the vertical ultimate bearing capacity of suction pile,and has certain guiding significance for the stability and safety evaluation of suction pile.