软土固结的负摩阻力对斜顶桩接岸结构影响

The effect of negative skin friction caused by consolidation of soft soil on inclined pile link-banked structure

上海洋山港高桩码头后方挡土结构采用斜顶桩接岸结构,目前软土固结对该结构的负摩阻力影响研究仍较缺乏。为对我国今后深水建港积累经验,采用有限元仿真技术,以洋山港一期工程斜顶桩接岸结构作为原型,分析施工期抛填成陆后各桩负摩阻力随软土固结发展的规律,并以原型观测数据验证了数模结果。研究结果表明:软土固结导致桩周土体发生相对桩基的竖向位移,在各桩表面产生负摩阻力,且软土固结主要发生于主固结阶段。在该阶段内,负摩阻力的发展具有时间效应,会在桩基表面形成下拉荷载,其对板桩、支撑桩的影响更大,建议采取多种措施削弱负摩阻力的不利影响。

Inclined pile link-banked structure is used as a kind of retaining structure behind the high-piled wharf in Shanghai YangShan harbor.At present,there is little research about the effect of negative skin friction caused by consolidation of soft soil on this structure.In order to accumulate experience in China’s deep-water harbor construction in the future,in this paper,the finite element simulation technique is used to simulate the YangShan harbor phase I project,which is took as the prototype.Then the law of the development of negative skin friction over each pile is analyzed after the construction of the land,and the numerical result is verified by the prototype observation data.The results show that the relative vertical displacement is caused by the soft soil around piles because of consolidation,so that the negative skin friction appears on piles’surface.Besides,consolidation of soft soil is mainly completed in the main consolidation stage.During this stage,the development of negative skin friction presents the time effect,and it will form a downward load on the surface of each pile,which has a greater effect on the sheet pile and the supporting pile.It is suggested that various measures should be taken to weaken the adverse effects of negative skin friction.