Pasternak地基中H(t)-V受荷桩水平响应有限杆单元法分析
Analysis of Lateral Response of H(t)-V Loaded Pile in Pasternak Foundation by Finite Beam Element Method
江杰 1艾永林 2柴文成 2龚健 2欧孝夺 1邵云怡3
作者信息
- 1. 广西大学 土木建筑工程学院,广西 南宁,530004;广西大学 特色金属材料与组合结构全寿命安全国家重点实验室,广西 南宁,530004;广西瑞宇建筑科技有限公司,广西 南宁 530299
- 2. 广西大学 土木建筑工程学院,广西 南宁,530004;广西大学 特色金属材料与组合结构全寿命安全国家重点实验室,广西 南宁,530004
- 3. 中船第九设计研究院工程有限公司,上海 200063
- 折叠
摘要
为探讨桩顶水平动荷载H(t)与竖向荷载V联合作用下桩基的水平响应,基于Pasternak地基和Euler梁理论,建立了桩-土相互作用水平振动分析模型,采用改进的有限杆单元方法求解考虑P-Δ效应、土体剪切效应影响的综合刚度矩阵方程,结合桩土连续边界条件得到桩身内力与位移解答.通过与已有解析解、有限元解和模型试验的结果比较,验证了计算方法的合理性.最后,对影响桩身内力与位移的主要因素进行分析.结果表明:1)传统Win-kler地基相较于Pasternak地基模型,忽略了地基土体的剪切效应,将夸大桩体结构的实际受力,使得计算得到的桩身水平位移和弯矩均大于Pasternak地基所得结果,且随着桩土弹模比Ep/Es的降低,两种地基模型计算的桩身最大水平位移和弯矩的差异性呈现出增强趋势;2)随着桩顶竖向荷载的增加,桩身水平位移和弯矩受P-Δ效应的影响显著.当桩顶竖向荷载特征参数λ由0增至2时,桩身最大水平位移和弯矩分别提高40.85%和78.57%;3)相较无限长桩(L>20dp),有限长桩的水平位移和弯矩的动力响应受桩身长径比L/dp影响更大;桩身最大水平位移和弯矩随着水平简谐荷载幅值H0的增加而增大,随着无量纲频率a0的增大而减小.
Abstract
To investigate the lateral response of a pile under the combined action of lateral harmonic load H(t)and vertical load V at the top of the pile,based on the Pasternak foundation and Euler beam theory,a lateral vibration analysis model of pile-soil interaction is established.The improved finite beam element method is used to solve the comprehensive stiffness matrix equation considering the P-Δ effect and soil shear effect,and the corresponding analytical solution is obtained by combining the pile-soil continuous boundary conditions.The rationality of the proposed method is verified by comparing its predictions with the results of existing analytical solutions,finite element solutions,and model tests.Finally,the main factors affecting the internal forces and deformations of the pile are analyzed.The results show that:1)Compared with the Pasternak foundation model,the traditional Winkler foundation ignores the shear effect of the foundation soil,which exaggerates the actual force of the pile so that the calculated lateral displacement and bending moment of the pile are larger than the results obtained by the Pasternak foundation.Additionally,as the pile-soil elastic modulus ratio(Ep/Es)decreases,the difference in maximum lateral displacement and bending moment between the two foundation models becomes increasingly pronounced;2)As the vertical load on the pile head increases,the lateral displacement and bending moment of the pile are significantly affected by the P-Δ effect.When the characteristic parameter λ of the vertical load on the pile head increases from 0 to 2,the maximum lateral displacement and bending moment of the pile increase by 40.85%and 78.57%,respectively;3)Compared with the infinite pile(L>20dp),the dynamic response of the lateral displacement and bending moment of the finite pile is more affected by the slenderness ratio L/dp;The maximum lateral displacement and bending moment of the pile increase with the increase of the amplitude of the horizontal harmonic load H0,and decrease with the increase of the dimensionless frequency a0.
关键词
水平动荷载/轴向荷载/有限单元法/Pasternak地基/动力响应Key words
horizontal harmonic load/axial loads/finite element method/Pasternak foundation/dynamic response引用本文复制引用
基金项目
国家自然科学基金资助项目(52068004)
出版年
2024
国家科技期刊平台
NSTL
万方数据