摘要
采用有限元法对高层建筑桩筏基础-地基-上部结构共同作用和相互影响进行分析研究。分析结果显示:与不考虑共同作用对比,上部结构中柱轴力减小,角柱和边柱轴力增大,考虑共同作用下,上部结构柱产生了不可忽略的弯矩,基础平均沉降和差异沉降均有所减小,由差异沉降引起的筏板内力减小。工程桩桩顶反力角桩最大、边桩次之、中心桩最小,角桩、边桩、中心桩桩顶反力与所有工程桩的桩顶反力平均值的比值为:1. 33,1. 06,0. 68。随着上部楼层的增加,基础中心沉降基本上呈线性增大。当上部结构施工至8层时,作用在桩顶的荷载达到了工程桩的单桩承载力特征值。上部结构层数不高于8层时,由于桩土刚度差异大,大部分上部荷载由桩承载,地基土荷载分担比例保持在15%～16%之间;上部结构高于8层后,桩顶荷载达到了工程桩的承载力特征值,基础沉降加大,地基土更多的参与分担上部荷载。
Finite element method was used to study the interaction and common effect among piled raft foundationfoundation-superstructure. The analysis results show that compared with not considering the joint action,the axial force of internal columns reduces along with the increase of the axial force of corner columns and side columns. Under the consideration of the joint action,the bending moment of columns is non-ignorable. The foundation settlement and different settlement reduce along with the reduction of internal force of raft. The reaction force at the corner pile top is larger than that of side pile. The reaction force at the internal pile is minimal. The ratio of reaction force at the corner pile top,side pile top and internal pile top to average value reaction force at all pile top is 1. 33,1. 06,0. 68. The settlement of corner point of foundation increases linearly with the increase of the floor. When the super structure is constructed to the 8 layer,the reaction force at the pile top reaches the characteristic value of the vertical bearing capacity of a single pile. When the floor is below 8 layers,most of the structural load is loaded by the pile because of the difference of stiffness between the pile and soil and the load sharing ratio of soil is keeps between 15% ~ 16%. When the superstructure is higher than the8 layer,the pile top load reaches the characteristic value of the bearing capacity of the engineering pile and the load sharing ratio of soil increases along with the increasing of foundation settlement.
作者
王磊
任彦华
Wang Lei;Ren Yanhua(Tianjin Institute of Geotechnical Investigation & Surveying,Tianjin 300191,China)
出处
《建筑结构》
CSCD
北大核心
2018年第S2期801-805,共5页
Building Structure
关键词
高层结构
桩筏基础
上部结构
共同作用
有限元
high-rise building structure
pile raft foundation
super structure
interaction and common effect
finite element
