长径比与桩侧土体模量变化对灌注桩竖向承载特性影响分析  

Effects of Pile Length-Diameter Ratio and Soil Modulus on the Vertical Bearing Characteristics of Filling Piles

作　　者：许白杨 杨珂 范金海 施文辉 吴悦 Xu Baiyang;Yang Ke;Fan Jinhai;Shi Wenhui;Wu Yue(Sichuan Transportation Construction Group Co.,Ltd.,Chengdu 610047,China;School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China;Chongqing Construction Science Research Institute Co.,Ltd.,Chongqing 400016,China;Chongqing Jianzhu College,Chongqing 400072,China)

机构地区：[1]四川省交通建设集团有限责任公司,四川成都610047 [2]重庆交通大学土木工程学院,重庆400074 [3]重庆市建筑科学研究院有限公司,重庆400016 [4]重庆建筑工程职业学院,重庆400072

出　　处：《市政技术》2024年第4期54-61,77,共9页Journal of Municipal Technology

基　　金：中国博士后科学基金(2023MD734112)。

摘　　要：为研究桩基长径比与灌注桩成孔开挖过程引起的桩侧土体弹性模量弱化效应对桩基承载特性的影响,采用数值分析方法构建了15组竖向受荷单桩模型,以分析桩顶荷载-沉降曲线、桩身轴力变化曲线和桩端荷载-沉降曲线的变化特征。结果表明,在同一桩长和桩顶竖向荷载下,桩顶竖向位移随着桩径的增大而减小,而在同一桩顶竖向位移下,桩顶竖向荷载随着桩径的增大而增大;在同一桩径和桩顶竖向荷载下,桩顶竖向位移随着桩长的增大而减小,而在同一桩顶竖向位移下,桩顶竖向荷载随着桩长的增大而增大。存在一临界长径比,使得桩端阻力发挥比例和桩顶竖向位移变化率的影响达到最大。当桩侧土体弹性模量大于某一定值时,桩侧土体弹性模量变化对桩承载特性的影响可忽略;随着桩侧土体弹性模量减小且达到某一定值时,桩侧摩阻力开始不发挥的位置逐渐向上移动。In order to study the influence of length-diameter(L/D)ratio and the weakening effect of elastic modulus of soil body on the pile side caused by the process of pile hole formation and excavation on the bearing characteris-tics of pile foundation,15 sets of vertically loaded mono-pile were conducted by numerical analysis in this paper to analyze the characteristics of load-settlement curve at the top of the pile,the change curve of the pile axial force and the load-settlement curve at the end of the pile.The results show that the vertical displacement at the top of the pile decreases with the increase of pile diameter under the same pile length and vertical load at the top of the pile.Under the same vertical displacement at the top of the pile,the vertical load at the top of pile increases with the increase of pile length;Under the same pile diameter and vertical load at the top of the pile,the vertical displacement at the top of the pile decreases with the increase of the pile diameter.Under the same vertical displacement at the top of the pile,the vertical load at the top of the pile increases with the increase of the pile diameter.There is a critical LID ratio that maximizes the influence of the percentage of resistance exerted at the end of the pile and the change rate of vertical displacement at the top of the pile.When the elasticity modulus of soil body on the pile side is greater than a certain value,the effect of the modulus change on the pile foundation bearing characteristics can be neglected;With the decrease of elasticity modulus of soil body on the pile side to a certain value,the position where the resistance on pile side is off working gradually shifts upward.

关 键 词：桩基承载特性 长径比 弹性模量 荷载-沉降曲线 数值模拟 

分 类 号：TU43[建筑科学—岩土工程]