沉垫自升式平台迁移工况桩腿力学研究

以普通自升式平台桩腿弯矩分析为基础,研究沉垫自升式平台迁移工况下桩腿的弯矩情况。建立沉垫自升式平台横摇力学模型,对平台迁移工况下的横摇状态进行力学分析,分别推导普通自升式平台和沉垫自升式平台桩腿惯性弯矩及总弯矩公式,并分析沉垫位置与桩腿弯矩的关系。以某沉垫自升式平台为例,研究沉垫处于不同位置时桩腿弯矩的变化规律,并与相同状况下的普通自升式平台桩腿弯矩情况进行对比。研究结果表明:沉垫的存在会增大桩腿在主甲板处的惯性弯矩;主甲板以上桩腿长度减小,沉垫与主甲板的距离增大,则风力、重力产生的弯矩减小,惯性弯矩增大。惯性弯矩是总弯矩变化的决定因素。随着沉垫的下降,桩腿总弯矩呈线性上升。

Mechanical study on legs of mat supported jack up platform under towing condition

Towing condition of the mat supported jack up platform was introduced briefly. Based on the bending moment study on legs of common jack up platform, the bending moment of mat supported jack up platform was studied. Force analysis on jack up platform was made when it was in rolling state. The formulas of inertia bending moment and total bending moment were deduced respectively. Based on these bending moment formulas, the relationship between location of mat and bending moment of leg was researched. The bending moment change of legs in different mat location was studied based on a real jack up platform. A comparison between mat supported and common jack up platform was made at last. Research results show that the existence of the mat can increase the inertia bending moment of the leg at the main deck. If the leg length above the main deck decreases and the distance between the mat and the main deck increases, the bending moment caused by wind force and gravity may increase. Inertia moment is the dominant factor to the variation of the overall moment. The overall bending moment of the leg increases linearly with the decline of the mat.