基桩负摩阻力时间效应的有限元分析  

Finite Element Analysis of Time Effect to Negative Skin Friction of Piles

作　　者：夏力农[1] 聂重军[1] 刘建平[1] 

机构地区：[1]长沙学院土木工程系,湖南长沙410003

出　　处：《湘潭大学自然科学学报》2009年第1期109-112,共4页Natural Science Journal of Xiangtan University

基　　金：湖南省教育厅资助项目(07C138);长沙学院引进人才启动项目

摘　　要：分析了桩顶荷载对于负摩阻力桩基荷载传递性状的影响.采用有限元方法模拟了基桩负摩阻力随着固结时间的变化.计算结果表明,随着土体固结时间的延续,在有无桩顶荷载的两种情况下,负摩阻力引起的桩身附加轴力均逐渐增加.与无桩顶荷载比较,桩顶荷载的作用使得中性点的位置明显上移,负摩阻力引起的下拽力减小.桩顶荷载推迟了负摩阻力出现的时间并使得负摩阻力引起的桩身附加轴力有所减小.不考虑桩顶荷载的负摩阻力的分析方法过高估计了下拽力,中性点的位置低于计算结果,正确的分析方法应当考虑桩顶荷载作用.Influence of working load on load-transfer properties in negative skin friction pile is simply analysed. Change of negative friction in pile with consolidation time is simulated by finite element method. Resuits show that additional axial force caused by negative skin friction increase gradually as consolidation time lapsing in both loaded and unloaded pile. Working load makes neutral point upward evidently, makes downdrag caused by negative friction play down comparing with unloaded pile. Working load postpone appearance of negative friction and reduce the additional axial force caused by negative friction. It is pointed out that routine negative friction analysis taking no working load into account overestimate the downdrag, location of neutral point lower than that in analysis result. Reasonable negative friction analysis should rake working load into account.

关 键 词：负摩阻力 时间效应 有限元 固结 中性点 

分 类 号：TU473.1[建筑科学—结构工程]