摘要
为了控制道路建设成本和满足道路线形需要,黄土沟壑区修建的桥梁桩基多处于斜陡坡上,因其存在桩侧土的缺失效应和桩侧土压力的削弱效应,降低了桩基竖向承载力,从而导致采用现行规范计算黄土沟壑区桩基竖向极限承载力偏不安全问题。结合黄土沟壑区的土质特性和背景工程的桩型特征,根据斜陡坡桩基竖向承载机理,建立了考虑边坡系数与临坡距耦合作用的黄土沟壑区桩基竖向承载力计算模型。运用FLAC 3D有限差分计算软件,研究边坡土体缺失效应和削弱效应对斜陡坡地形桩基承载力的影响,并通过回归拟合方法,建立黄土沟壑地形竖向桩基承载力计算公式。研究结果表明:黄土沟壑地形对桩端摩阻力的影响可以忽略,但对于桩侧摩阻力的影响不容忽略;边坡系数和临坡距对桩基竖向承载力的影响成相互耦合关系,桩侧摩阻力随着临坡距和边坡系数的增加而增加,且桩侧摩阻力增加量越来越慢;临坡距为1d时(d为桩径),边坡系数从0.57增加到1.00时,桩侧极限摩阻力增加了91.6%,边坡系数从1.73增加到3.73时,桩侧极限摩阻力增加了22.2%;临坡距为10d时,边坡系数从0.57增加到1.00时,桩侧极限摩阻力增加了37.4%,当边坡系数从1.73增加到3.73时,桩侧极限摩阻力增加了18.3%。提出的桩基竖向承载力公式计算结果与数值模拟结果基本一致,可为同类桩基承载力计算提供参考。
In order to control the cost of road construction and meet the requirements of road alignment,the bridge pile foundation in the Loess Gully Region was built on a steep slope.Pile foundations built on steep slopes were unsafe when calculating the vertical ultimate bearing capacity of pile foundations in Loess Gully Region,because of the lack of soil failure and the weakening effect of soil pressure on pile side,which reduces the vertical bearing capacity of pilefoundations.Based on the soil properties and pile type characteristics of background engineering in Loess Gully Region and the vertical bearing mechanism of pile foundation on steep slope,a calculation model of vertical bearing capacity of pile foundation in Loess Gully Region considering the coupling effect of slope coefficient and distance between adjacent slope was established.FLAC3 Dfinite difference calculation software was used to study the influence of soil failure and weakening effect on the bearing capacity of pile foundation on steep slope terrain.The formula for calculating the bearing capacity of vertical pile foundation on Loess Gully terrain was established by regression fitting method.The results show that the influence of Loess Gully topography on pile tip friction can be neglected,but the influence on pile side friction can not be neglected.The influence of slope coefficient and slope spacing on the bearing capacity of pile foundation shows a coupling relationship.The pile side friction increases with the increase of slope spacing and slope coefficient,and the increase of side friction becomes slower and slower.When the slope spacing is 1 d,dis the pile diameter,the slope coefficient increases from 0.57 to1.00,the side friction increases by 91.6%,and when the slope coefficient increases from 1.73 to3.73,the side friction increases by 22.2%.When the slope spacing is 10 d,the slope coefficient increases from 0.57 to 1.00,the side friction increases by 37.4%,and when the slope coefficient increases from 1.73 to 3.73,the side friction increases
作者
段瑞芳
王鼎
韩军舵
王晓明
DUAN Rui-fang;WANG Ding;HAN Jun-duo;WANG Xiao-ming(School of Highway and Railway Engineering,Shaanxi College of Communication Technology,Xi'an 710018,Shaanxi,China;Rizhao City Highway Bureau,Rizhao 276800,Shandong,China;Key Laboratory of Bridge Detection Reinforcement Technology of Ministry of Communication,Xi'an 710064,Shaanxi,China;CCCC First Highway Consultants CO.,LTD.,Xi'an 710075,Shaanxi,China)
出处
《长安大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2019年第1期99-106,共8页
Journal of Chang’an University(Natural Science Edition)
基金
陕西省教育厅专项科学研究计划项目(17JK0070)
国家自然科学基金项目(51308055)
关键词
桥梁工程
斜陡坡
竖向承载力
边坡系数
临坡距
桩基
黄土沟壑区
bridge engineering
steep slope
vertical bearing capacity
slope coefficient
slope distance
pile foundation
Loess Gully Region
