带承台群桩负摩阻力性状的三维有限元分析  

Three-dimensional finite element analysis of negative skin friction behaviors in pile groups with cap

作　　者：夏力农[1,2] 苗云东[1] 谈铁强[2] 

机构地区：[1]湘潭大学土木工程与力学学院,湖南湘潭411105 [2]长沙学院土木工程系,长沙410003

出　　处：《岩土力学》2012年第3期887-891,898,共6页Rock and Soil Mechanics

基　　金：长沙市科技计划项目;长沙学院引进人才科研基金

摘　　要：无承台群桩中各桩的桩-土相互作用是相互独立的,带承台群桩的桩-土相互作用要受到承台的约束。简要分析了带承台群桩负摩阻力变化的机制。采用三维有限元分析了地下水位下降条件下带承台群桩的负摩阻力性状。分析结果表明,带承台群桩的负摩阻力与单桩负摩阻力总体相近,随着上部荷载的增大,中性点上升,附加沉降增加,下拉力减小,只是各位置桩有差异。荷载不大时,承台对各位置桩沉降的约束明显,各桩中性点几乎重叠。随着荷载的增加,承台本身变形增加,中性点的差异逐渐变得明显,角桩中性点位置最低,边桩次之,中心桩最高。带承台群桩中各桩的负摩阻力沿着深度的发挥程度不同。角桩负摩阻力发挥最为充分,边桩次之,中心桩最小。The pile-soil interactions are constrained by the pile cap in pile groups with cap,while mutually independent in pile groups without cap.The mechanism of negative skin friction variation in pile groups with cap is analyzed briefly.Under the condition of groundwater level falling,the negative skin friction behaviors of pile groups with cap are analyzed by three-dimensional finite element method.The analytical results show that the negative skin friction of pile groups with cap is generally similar to that of a single pile： as the loads on cap increasing,the neutral point moves up,additional settlement increases and the downdrag decreases,though there are differences between piles in different positions.The constraints of settlement of piles in various positions by the cap are significant when the load is not large;so that the neutral point of piles are almost coincident.As the load increasing,the deformation of the cap increases and the neutral points of piles become more various,lowest for the corner pile,second for the perimeter pile and highest for the center pile.The negative skin friction of each pile in pile groups with cap mobilizes differently along the depth.It is mobilized most fully for the corner pile,second for the perimeter pile and least for the center pile.

关 键 词：带承台群桩 地下水位下降 负摩阻力 性状 有限元法 

分 类 号：TU443[建筑科学—岩土工程]