摘要
多层地基水平受荷桩的受力变形特性分析是设计中的关键步骤。针对传统有限单元法在准确性与计算效率上的不足,提出了一种用于分析该类桩基的高性能有限单元法。该法构建了一种桩单元,并采用分布在单元内部的连续"土体弹簧"反映非线性桩-土相互作用。其最大特点是在桩单元内部整合了"土体弹簧",即桩单元同时包含了桩体与土体信息。推导了适用于多层地基中的桩单元,并引入高斯-勒让德方法简化总势能求和过程;推导了单元刚度矩阵并运用在牛顿-拉夫逊增量迭代数值分析中,引入割线关系减少迭代过程中的累计误差。此外,该法还通过更新拉格朗日方法来考虑几何大变形。算例结果表明:高性能有限单元法与解析解及现场试验结果吻合较好;在多层地基条件下,桩单元模型较离散弹簧单元模型可大幅减少单元数目及计算时长,可有效提高计算效率。
Mechanical analysis of laterally-loaded piles embedded in multi-layered soils is a critical step in design.Traditional finite-element method may have deficiency in accuracy and efficiency when applied to analyze this problem.An efficient finite-element method is proposed in this paper.A"pile element"that adopts the distributed"soil springs"along the element length to reflect the nonlinear behaviors of the pile-soil interactions is developed in this method.The dominant feature of the pile element is the direct integration of soil properties into the element formulation,namely,a pile element comprises both the pile and soil properties.The pile element formulation in multi-layered soils is derived,and the Gauss-Legendre method is introduced to simplify the total potential energy summation process.The element stiffness matrix is derived and applied to Newton-Raphson incremental iterative numerical process,and the secant relations are used to minimize the cumulative errors during the numerical iteration process.Besides,the updated Lagrangian method is employed to account for the large deformation issue.Results show that:1)the proposed method can provide predictions that match well with both the theoretical solutions and field test data;2)using the pile element model can substantially reduce the number of elements and calculation time compared with those of the discrete element model,and thus significantly improve the calculation efficiency.
作者
赵海鹏
黎学优
万建宏
郑翔之
刘思威
ZHAO Hai-peng;LI Xue-you;WAN Jian-hong;ZHENG Xiang-zhi;LIU Si-wei(School of Civil Engineering,Sun Yat-Sen University,Guangzhou,Guangdong 510275,China;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai,Guangdong 519082,China;Department of Civil and Environmental Engineering,The Hong Kong Polytechnic University,Hong Kong 999077,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2021年第7期1995-2003,2014,共10页
Rock and Soil Mechanics
基金
国家自然科学基金项目(No.51909288)
广东省科技厅项目(No.2019ZT08G090)。
关键词
水平受荷桩
有限单元法
桩-土相互作用
桩单元
多层地基
laterally-loaded piles
finite element method
pile-soil interaction
pile element
multi-layered soils
