舟山某海域海上自升式平台桩基稳定性研究

Pile Foundation Stability Analyses of Offshore Jack-up Platform in Zhoushan Sea Area

地基承载力和地基沉降分析对自升式海洋平台安全作业极为重要。以舟山某海域自升式海洋平台为研究对象,分别采用理论分析和数值模拟的方法对不同入泥深度的桩靴地基承载力和沉降进行计算分析,并开展桩靴几何尺寸对地基承载力影响的敏感度分析。研究结果表明:(1)采用《海洋井场调查规范》理论分析和FLAC;数值模拟所得到的桩靴安全插桩深度分别为15 m和14 m,结果接近。(2)采用《建筑地基基础设计规范》和FLAC;数值模拟得到的地基沉降量分别为335.61 mm和260.55 mm,相差约28.8%。(3)方形桩靴的长度对地基承载力的影响最大,桩靴长度增加11%,相应的地基承载力增加27%,桩靴高度和桩腿直径对地基承载力影响可以忽略不计。

The analysis of foundation bearing capacity and foundation settlement is extremely important for the safe operation of jack-up offshore platforms.Taking a jack-up offshore platform in Zhoushan sea area as the research object,theoretical analyses and numerical simulations are used to calculate the bearing capacity and settlement of pile shoe foundations at different depths of mud.The influence of pile shoe geometry size on foundation bearing capacity is also carried out.Research results show that:(1)The safe insertion depths of pile shoes obtained by theoretical analysis using“Ocean Wellsite Survey Specifications”and FLAC;numerical simulation are 15 m and 14 m,respectively.(2)The foundation settlements obtained by the“Code for Design of Building Foundation Foundations”and FLAC;numerical simulation are 335.61 mm and 260.55 mm,respectively,with a difference of about 28.8%.(3)The length of the square pile shoe has the greatest influence on the bearing capacity of the foundation.The length of the pile shoe increases by 11%,and the corresponding foundation bearing capacity increases by 27%.The influence of the height of the pile shoe and the diameter of the pile leg on the bearing capacity of the foundation is negligible.