海上升压站平移过程中自升式工作船桩靴沉降分析方法

Analysis Method on Settlement of Spudcan of Jack-Up Platform during Translational of Offshore Substation

目前尚无针对海上升压站平移过程中自升式工作船沉降分析的具体方法及相关研究,因此急需明确上部组块平移过程中自升式工作船桩靴沉降情况。首先根据相关理论计算出自升式工作船所受的自重荷载及风、浪、流荷载;然后基于ABAQUS有限元软件创新性地建立自升式工作船实体-桩靴基础-地基土体整体结构数值分析模型,进而对不同桩靴沉降进行分析,并与分层总和法理论计算结果对比,验证了数值模型的合理性与准确性;最后进行上部组块运输过程安全性评价。结果表明:上部组块平移过程中桩靴竖向压力占自升式工作船预压载荷的20%,满足竖向承载力施工要求。此外,桩靴基础沉降量受外部荷载影响沉降变形波动明显,最后逐渐趋于稳定,最终沉降约为11.45 mm,并与理论计算结果相符,轨道的纵向坡度为0.38%,能够达到安全运输标准。该研究成果对确保海上升压站上部组块平移过程顺利进行具有理论指导和现实意义。

At present, there is no specific method or research on the settlement analysis of jack-up platform during the moving process of offshore substation, therefore it is imperative to clarify the settlement of jack-up rigs during the moving process of topside. Various calculated loads, including self-weight, wind, wave and current are analyzed first based on the relevant theory, then a whole numerical calculation model of the jack-up rig-spudcans-soil foundation are established creatively using ABAQUS, and then based on this, the settlements of spudcans under different conditions are calculated, which are compared with the theoretical calculation results of the layered summation method, then the reasonableness and accuracy of the numerical model is verified.Finally, the evaluation of safety is carried out during the transporting process of the offshore substation. The results show that the vertical pressure of spudcans accounts for 20% of the pre-pressure load of the jack-up rig during the transportation of the topside, which meets the construction requirement in terms of the vertical bearing capacity. Besides, the settlement of the spudcans fluctuates significantly due to the influence of external loads,and finally reaching a stability gradually, with the final settlement of about 11.45 mm, which is in line with the theoretical calculation results from the layered summation method, and the longitudinal slope of the track is 0.38%, which can meet the safe transportation standards also. The research results of the resesarch are of theoretical guidance and practical meaning to ensure the horizontal transporting of the offshore substation safely.