黄土洞穴对桥梁桩基竖向承载特性影响的离心模型试验

发布时间：2018-01-30 11:49

本文关键词： 桥梁工程黄土洞穴桥梁桩基础竖向承载特性离心模型试验　出处：《长安大学学报(自然科学版)》2017年02期 　论文类型：期刊论文

【摘要】：为给黄土地下洞穴区域的桥梁桩基在设计计算方法和施工技术等方面研究提供依据,针对实际桥梁桩基遇到黄土地下洞穴时,往往盲目地对洞穴先处理再施工,既无法保证桩基安全,也不够经济合理等问题,基于铝管模拟桩体、可发性聚乙烯(expandable polyslyrene,EPE)塑料泡沫模拟黄土地下洞穴的离心模型试验,开展了黄土地下洞穴对桥梁桩基竖向承载特性的影响研究,分析了竖向荷载作用下桩与洞穴水平间距、洞穴发育深度及桩底与洞穴垂直间距等因素对桥梁桩基竖向承载力、桩身轴力和桩侧摩阻力的影响。研究结果表明:洞穴发育深度小于20m且桩与洞穴水平间距大于1.0倍桩径,桩与洞穴水平间距大于桩径的20%且洞穴发育深度小于5m,洞穴距桩底超过8m时,桩基竖向极限承载力受洞穴的影响均较小;随着桩与洞穴水平间距的增大,桩基竖向极限承载力逐渐提高,水平间距越小,桩侧摩阻力越小,桩身轴力有所增大;随着桩底与洞穴垂直间距的逐渐增大,桩基竖向极限承载力逐渐增大,垂直间距越小,桩侧摩阻力发挥越完全,桩身轴力衰减越快;相同荷载作用下,桩与洞穴水平间距越小,洞穴发育深度越深,桩侧摩阻力越小;桩顶荷载较小时,桩底与洞穴垂直间距越小,桩侧摩阻力越大。研究成果可为黄土地下洞穴区域桥梁桩基础的设计提供技术依据。
[Abstract]:As the calculation method and construction technology for bridge pile foundation design in loess area of underground cave provide the basis, according to the actual bridge pile in Loess encountered underground caves, often blindly on the first cave treatment and construction, not only can not guarantee the safety of pile foundation, problem is not reasonable, aluminum pipe pile based on the simulation, can be made of polyethylene (expandable polyslyrene, EPE) centrifugal model test of plastic foam simulation of loess caves, the influence of the Loess underground cave on bearing characteristics of bridge pile foundation, analyzed the vertical loads and the horizontal spacing of pile cave, cave and cave depth and pile bottom vertical spacing and other factors on the vertical bearing capacity of bridge pile foundation the influence of pile, axial force and lateral friction resistance. The results show that: the cave depth is less than 20m and the pile and the cave level spacing is greater than 1 times of the pile diameter, pile and The cave level spacing is larger than the pile diameter and depth is less than 5m 20% caves, cave from the pile bottom is more than 8m, are less affected by the cave pile vertical bearing capacity limit; with the increase of pile spacing and the cave level gradually increased, the pile vertical bearing capacity limit, the level spacing is small, pile side friction resistance is small the axial force of pile increases with the pile bottom; and the vertical spacing between the cave increases gradually, gradually increase the ultimate vertical bearing capacity of pile foundation, vertical spacing is small, pile friction more completely, the axial force of pile decreased more quickly; the same loads, pile and cave level spacing is small, the depth of cave development deep pile side friction resistance is smaller; load on pile top is small, and the cave pile bottom vertical spacing is smaller, the pile side friction is greater. Provide the technical basis for the design of research results for the loess cave area underground bridge pile foundation.

【作者单位】：长安大学公路学院;中国电建西北勘测设计研究院有限公司;中国建筑第七工程局有限公司技术中心;广东省南粤交通投资建设有限公司;广东省交通规划设计研究院股份有限公司;广东大潮高速公路有限公司;湖北省交通投资集团有限公司;
【基金】：陕西省自然科学基础研究计划项目(2013JM7016)
【分类号】：U443.15
【正文快照】： Centrifuge model test on effect of underground loess cave on verticalbearing characteristic of bridge pile foundationFENG Zhong-ju1,WANG Fu-chun1,SU Hang-zhou1,2,HAN Qiu-shi 3,XI Chen-xin1,4LI Yan5,YIN Hong-hua1,JIAN Xin-long1,6,LIANG Qian1,7(1.School of

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