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地震作用下斜坡桥梁桩基动力响应及变形特征

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[目的]研究斜坡桩基在地震作用下的动力响应及其变形特征,为山区的桥梁桩基设计和施工提供参考.[方法]利用颗粒离散元软件建立斜坡桩基模型,通过参数标定得到模型细观参数,以动力边界条件完成地震波加载过程.考虑桩基形式和斜坡坡度,分析地震过程中斜坡动力响应规律及桩基的受力与变形特征.[结果]数值模拟结果表明,群桩基础斜坡场地的震动变形破坏程度较单桩基础的小,且斜坡坡度的增大会使场地变形破坏更加严重.坡脚和坡内测点的加速度放大系数比坡肩测点的分别减小27.7%和37.9%,这表明坡肩测点的加速度放大效应更为显著.各桩基桩身弯矩最大值均出现在基岩面附近.在斜坡坡度为30°和45°时,双桩群桩基础桩身最大弯矩绝对值较单桩基础的分别减小18.4%和19.8%;而当桩基形式为单桩和双桩群桩基础时,斜坡坡度为45°的桩身最大弯矩绝对值较斜坡坡度为30°的分别增大9.7%和7.9%.桩身最大水平位移发生在桩顶处.群桩基础的最大桩身弯矩和水平位移都较单桩基础的小.斜坡坡度越大,群桩基础的最大桩身弯矩和水平位移都有所增大.[结论]桩基的形式和斜坡坡度对桩基动力响应和桩身受力变形均有较大影响.在桩基设计选址时,合理选择桩基的位置和形式可有效提高桥梁桩基在斜坡上的抗震效果.
Dynamic response and deformation characteristics of pile foundations for bridges on slopes under earthquake action
[Purposes]This paper aims to study the dynamic response and deformation characteristics of pile foundations on slopes under earthquake action,so as to provide a reference for the design and construction of pile foundations for bridges in mountainous areas.[Methods]The particle flow simulation software was used to establish a pile foundation model on a slope,and the detailed parameters of the model were obtained through parameter calibration.The loading of seismic waves was accomplished with the setting of dynamic boundary conditions,and the forms of the pile foundation and the slope were considered to analyze the dynamic response law of the slope and the force and deformation characteristics of the pile foundation during earthquakes.[Findings]Numerical simulation results show that the vibration deformation damage of the slope site with a group pile foundation is smaller than that of the single pile foundation,and the increase in the slope will make the site deformation damage more serious.Compared with the slope shoulder,the acceleration amplification coefficients of the measuring points at the foot of the slope and inside the slope decrease by 27.7%and 37.9%,respectively,indicating that the acceleration amplification effect at the slope shoulder is more significant.The maximal bending moment of the pile body of each pile foundation occurs near the bedrock face,and the absolute values of the maximal bending moment of the pile body of the two-pile group foundation decrease by 18.4%and 19.8%compared with that of the single-pile foundation at the slopes of 30° and 45°,respectively.The absolute values of the maximal bending moment of the pile body at the slope of 45° increase by 9.7%and 7.9%compared with that at the slope of 30° when the pile foundation is in the form of the single-pile and the two-pile group foundations,respectively.The maximal horizontal displacement of the pile body occurs at the top of the pile,and the maximal bending moment and horizontal displacement of the pile body of the group pile foundation are smaller than those of the single-pile foundation.A larger slope indicates increased bending moment and horizontal displacement of the pile body of the pile foundation.[Conclusions]The forms of pile foundation and slope have a great influence on the dynamic response of pile foundation and the deformation of pile bodies.In pile foundation design,a reasonable selection of pile foundation locations and pile foundation forms can effectively improve the seismic resistance of pile foundations for bridges on slopes.

bridge engineeringpile foundation on slopeparticle flow codedynamic response of sitedeformation characteristics of pile body

陈源锋、付亚伟

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广西桂通工程管理集团有限公司,广西 南宁 530029

广西桂中工程咨询有限公司,广西 柳州 545000

桥梁工程 斜坡桩基 颗粒离散元 场地动力响应 桩身变形特征

2024

长沙理工大学学报(自然科学版)
长沙理工大学

长沙理工大学学报(自然科学版)

影响因子:0.63
ISSN:1672-9331
年,卷(期):2024.21(6)