海洋双井口吸力桩井口间距设计方法

Design method for the spacing between the suction piles at the double well mouth of the ocean

海洋双井口吸力桩作为一种海上钻井结构,其井筒对称分布于桩体中轴线两侧。在钻完井及后续测试作业中,由于一侧井口承载较大的载荷,导致对吸力桩基础产生偏心载荷作用,影响结构稳定性。基于目标靶区土质情况及井口载荷,对外径为2~4 m的双井口吸力桩井口间距进行了设计分析。通过倾覆失稳理论,考虑了小位移失稳和大位移倾覆两种失稳模式,分析了环境载荷对结构稳定性的影响,并根据API相关规范选取了环境参数和安全系数。通过参数敏感性分析,确定了桩体高度、贯入深度和井口间距对倾覆性能的影响,并推荐了设计井间距为3.5 m,以确保结构的稳定性和防止井口设备互相干涉。

The ocean dual-borehole suction pile,with its boreholes symmetrically distributed on both sides of the pile's central axis,is subject to significant eccentric load effects during the drilling and subsequent testing operations due to the asymmetrical loading of one borehole.This study,based on the soil conditions of the target area and borehole loading,conducts a design analysis of the dual-borehole suction pile’s borehole spacing,specifically for an outer diameter of 2~4 meters.By applying the overturning instability theory,which encompasses two modes of instability—small displacement instability and large displacement overturning—the study examines the impact of environmental loads on structural stability.Environmental parameters and safety factors are selected in accordance with API standards.A sensitivity analysis of the pile Height,penetration depth,and borehole spacing parameters is performed to determine their effects on the pile’s overturning performance.The study recommends a borehole spacing of 3.5 meters to ensure structural stability and prevent interference between borehole equipment.