计入水平力剪切变形和轴力影响的柱单元及其在支座基桩共同作用分析中的应用  

Beam Element Considering Lateral Shear Deformation and Axial Force Effect and Its Application in Analysis of Bearing and Pile Combined Action

作　　者：李微哲[1,2] 娄平 

机构地区：[1]中南大学土木工程学院,湖南长沙410012 [2]中煤科工集团重庆设计研究院有限公司,重庆400016

出　　处：《公路交通科技》2018年第1期46-54,78,共10页Journal of Highway and Transportation Research and Development

摘　　要：基于王用中、Wilson E.L.和赵明华等分别提出的柱单元弹性刚度矩阵和几何刚度矩阵,推导了3种同时计入水平力剪切变形和轴力P-Δ效应的柱单元刚度矩阵方程,可模拟框架柱、剪力墙等小剪切变形轴力构件和支座等大剪切变形轴力构件的动静力工作,为计入剪切变形和轴力P-Δ效应的压弯剪构件静动力有限元分析提供了理论支撑。推导了另外两种形式的仅考虑轴力P-Δ效应的柱单元刚度矩阵方程。通过退化分析验证了本文理论推导正确。最后应用计入水平力剪切变形和轴力P-Δ效应的柱单元模拟支座偏心工作,并建立了支座基桩有限元模型,应用自编的Matlab有限元分析程序进行了案例分析。结果表明,计入水平力剪切变形和轴力效应的柱单元可较好地实时模拟支座大剪切变形下的偏心工作特性,竖向力因支座大水平剪切位移产生的偏心弯矩极为显著,对基桩受力特性影响较大,将进一步扩大轴力P-Δ效应,进而削弱基桩和支座的整体的水平刚度,有效增大了基桩内力和其等效计算长度,减小了支座基桩的整体水平抗推刚度,不容忽略;建议进行基桩设计计算以及水平力在墩台间分配计算时采用支座基桩共同作用有限元模型。Based on the elastic stiffness matrixes and the geometric stiffness matrixes of the beam elemen developed by Wang Yongzhong, E. L. Wilson and Zhao Minhua, 3 rigid matrix equations of beam element considering lateral shear deformation and axial force P -△ effect are derived to simulate the static and dynamic workings of small shear deformation axial forced components such as columns and shear walls and large shear deformation axial forced components such as bearings, which provides a theoretical support for static and dynamic FE analysis of the compressive, flexural, and shear components. Another 2 rigid equations of beam element only considering the axial force P - △ effect are derived. The theoretical derivation is proved to be correct by degradation analysis. Finally, the eccentric working of the bearing considering lateral shear deformation and axial force P - A effect is simulated, the finite element model of the pile of bearing is established, and the self-compiled Matlab finite element analysis program is used for case study. The result shows that （ 1 ） the beam element considering lateral shear deformation and axial force P - △ effect can better simulate the eccentric working characteristics of the bearing with large shear deformation; （2） the eccentric moment caused by vertical force due to large horizontal shear displacement of bearing is significant, it will remarkably affect the mechanical property of foundation pile, increase the axial force P - △ effect and decrease the composite horizontal rigidity of bearing and foundation pile, effectively increase the internal force and the equivalent calculation length of the pile, and reduce the overall horizontal anti push rigidity, which cannot be ignored. It is suggested that to use the finite element model of the pile and bearing combined action during the pile design and calculation of distribution of horizontal forces of piers.

关 键 词：桥梁工程 柱单元 有限元法 桩 水平力剪切变形 轴力P-△效应 支座 

分 类 号：TU375.4[建筑科学—结构工程]