海上平台桶形基础沉贯过程的数值分析.docVIP

海上平台桶形基础沉贯过程的数值分析 　　摘要： 探讨了桶形基础沉贯过程中负压引起的渗流场分布及其对桶壁与土体间的接触应力和摩擦阻力的影响。计算结果表明：负压沉贯过程中，桶内土体在离顶面约贯入深度一半的范围内产生负孔隙水压，该部分土体极易在负孔隙水压作用下发生破坏以至形成土塞；桶壁与土体间的接触正应力在沉贯过程中不断增加，并且与贯入深度成线性正比关系；负压主要减少桶壁内侧与土体间的摩擦力，而对桶壁外侧摩擦力无显著影响，因而，从整体上减少了桶体沉贯时所受的摩擦力。通过与求解沉贯过程中土体应力的解析公式进行对比，印证了本文计算结果的合理性，并提出了考虑初始应力的计算沉贯过程中桶-土接触应力的简化公式。 　　Abstract: The main objective is to research the seepage field that induced by the negative pore pressure during the penetration process of the bucket foundation, and also, to research the seepage fields influence to the contact stress and friction resistance between soil and bucket wall. The numerical calculation result show that: during the negative pore pressure penetration process, negative pore pressure will yield in the region about half the penetration depth of bucket under the seabed. Soil in this region will destroy into soil plug easily by the effect of negative pore pressure; the contact stress between soil and bucket wall will increase in the whole penetration process, and it has linear proportionality relation with the penetration depth; the negative pore pressure could decrease the friction resistance between the soil and inside of wall, but has little influence in the friction between the soil and outside wall, therefore, the whole friction resistance in the bucket could be decreased. The calculation results rationality is confirmed by the comparison with the analytical formula which is used to calculate the soils stress in the installation process, and then, a simplified formula is suggested to calculate the contact stress between soil and bucket with consideration of initial stress. 　　关键词： 桶形基础；负压沉贯；渗流场；桶-土接触应力；初始应力；简化公式 　　Key words: bucket foundation；suction penetration; seepage field；contact stress；initial stress；simplified formula 　　中图分类号：TV223.2 文献标识码：A文章编号：1006-4311（2011）02-0043-03 　　 　　0引言 　　吸力式桶形基础平台是近年来发展起来的一种新型海洋工程平台，由于它采用负压下沉施工技术，具有便于运输安装和可重复使用、造价低等优点，在浅海石油天然气资源的开采工程中有广泛的应用前景。目前对吸力式桶形基础的研究主要集中在静力稳定性及极限承载力方面，对于负压沉贯过程的研究尚未进行系统深入的研究。针对桶形