黎之奇 徐文祥

摘   要：为解决自升式平台在南海等软黏土区域作业时出现的穿刺问题，对平台桩靴在黏土中加载时出现的穿刺现象进行实验验证，并对穿刺机理和解决方案进行探索.以某大桩靴自升式平台的实际加载过程为原型，设计一套不连续加载的单桩模型插桩实验装置，通过力加载的方式模拟自升式平台预压载过程，分析插桩时的冲桩处理对穿刺风险的消除效果.研究结果表明：黏土层中不连续加载能够形成穿刺现象，并且减小加载速率在一定程度上可以降低穿刺风险;通过在加载过程中进行冲桩作业，能有效减少穿刺的发生.因此在实际工程中可通过选择合适的加载速率，并在加载过程中进行冲桩操作来降低穿刺风险，保证作业安全.

关键词：海洋平台;黏土;桩靴;穿刺;冲桩

中图分类号：TU411                               文献标志码：A

文章编号：1674—2974（2019）09—0108—07

Abstract：  In order to solve the punch-through problem of the Jack-up platform in the soft clay area such as the South China Sea， the punch-through phenomenon of the Jack-up platform when penetrating in clay was verified by experiment， and the mechanism and solution for the punch-through were explored. In this paper， an experimental set for single leg penetration test under discontinuous loading was designed to simulate the preloading process of a real Jack-up platform with large spud-can， and a series experiments were performed to investigate the effect of the water jetting process for eliminating the risk of punch-through. The results show that the punch-through can occur in the clay layer under discontinuous loading， and the risk of the punch-through can be mitigated by reducing the loading rate or performing water jetting process. Thus， the present investigation is beneficial for safety operation of the jack-up platform in practice.

Key words： marine platform;clay;spud-can;punch-through;waiter jetting

自升式海上石油鉆井平台因其定位能力强、作业灵活、可移动性能好、价格低廉等特点，在近海油气勘探开发中发挥着重要作用. 据统计，全球自升式钻井平台约占移动式钻井装置总数的二分之一，为石油勘探开发做出了巨大贡献[1].海上自升式钻井平台作业分为几步进行，先经过拖航、就位、放桩、插桩、预压、升船，然后才可以进行正常作业.其中在预压过程中，桩腿在船舱压载水等荷载作用下继续下沉，桩靴插入海底泥面以下，平台船体却在上升，而实际作业时通常采取分级加载方式，即平台所……