复杂土层中自升式平台桩靴安装穿刺预测

Prediction of punch-through during spudcan installation in complex soil profiles

由于复杂海洋工程地质条件的普遍性,自升式平台在安装过程中穿刺事故频发,近年来涌现出大量针对自升式平台桩靴基础在复杂土层中穿刺预测方法的研究。为了方便工程设计人员的理解和使用,首先简单介绍这些研究中所采用的技术手段,总结现行规范ISO 19905-1建议的桩靴在复杂土层中贯入阻力的预测方法以及最新文献中提出的新的设计方法,并对规范方法和新方法的优缺点进行了评价。所总结的设计方法针对国内外常见的含穿刺风险的海洋地基形式,包括双层"砂—黏"、三层"硬—软—硬"黏性土、三层"软—硬—软"黏性土、三层"黏—砂—黏"地层以及四层"黏—砂—黏—硬层土"地层。通过对离心机模型试验的预测,对规范方法和新方法的预测精度进行了比较,对比结果显示新方法对桩靴穿刺破坏的预测更为合理精确。

Due to the prevalence of complex soil conditions,punch-through incident occurs frequently during the installation of jack-up rigs. Therefore,a great number of studies have recently been carried out to develop new design approaches for predicting punch-through during spudcan penetration in complex soil profiles. The experimental and numerical techniques adopted in these studies are briefly introduced here,followed by a summary of the design approaches developed in these studies and those suggested by the current design guidelines ISO 19905-1. The advantages and disadvantages of the summarized design approaches are discussed,in particular for typical soil profiles encountered in the offshore fields including sand-over-clay,stiff-soft-stiff clay,soft-stiff-soft clay,clay-sand-clay,and clay-sand-clay-strong layer. The performances of the ISO-suggested approaches and the new approaches are compared through the prediction of centrifuge model tests,with the new approaches showing more reasonable and accurate agreement with the measured data.