竖向荷载下群桩的承载特性模型试验研究  

Experimental study on the bearing characteristics of pile groups under vertical loads using a model test

作　　者：李鹏 牛涛 张坦 游川波 李强 Li Peng;Niu Tao;Zhang Tan;You Chuanbo;Li Qiang(Road and Bridge International Co.Ltd Overseas Company,Beijing 100027,China)

机构地区：[1]中交路桥建设有限公司海外分公司,北京100027

出　　处：《建筑科学》2025年第1期20-32,共13页Building Science

摘　　要：随着工程建设的发展,群桩基础因承载力高、沉降小、稳定性好的特点而成为当今工程建设体系中不可或缺的基础形式之一。本文通过开展竖向荷载作用下不同形式的群桩静载模型试验,探究了其承载特性。试验结果表明:在饱和砂土地基中,群桩的荷载-沉降曲线与单桩曲线类似,均呈现陡降型,有明显拐点;由于桩-桩间土-周围地基土之间的相互作用,同一压桩速度沉桩完成后,单桩的桩周侧压力在距离桩径1D处最大,随着桩径的增加逐渐减小;群桩的桩周侧压力在距离桩径3D处最大且变化最明显,7D处最小;在相同等级的荷载作用下,九桩基础中桩身相同位置处,轴力总体表现出角桩大于边桩大于中心桩的规律,但不同位置的桩,轴力沿桩身减小趋势不同;对于群桩的桩侧摩阻力,各桩分布形式基本相同,在加载后期,随着桩土相互摩擦的叠加作用及桩间土的挤密作用,桩侧摩阻力最大值出现上移的趋势。With the development of engineering construction,pile group foundation has become one of the indispensable foundation forms in today's engineering construction system because of its high bearing capacity,small settlement and good stability.This paper investigates the bearing characteristics of different forms of group piles by carrying out static load model tests under vertical load.The test results show that:in saturated sandy soil foundation,the load-settlement curve of group piles is similar to that of single piles,showing a steep decline with obvious inflection points;due to the interaction between piles-inter-pile soils-surrounding foundation soils,after sinking the piles with the same compaction speed,the lateral pressure of the single pile is the largest at the distance of 1D from the pile diameter,which decreases with the increase of the pile diameter;the peripheral pressure of the pile group is the largest and the most obvious at 3D from the pile diameter,and the smallest at 7D.Under the action of the same grade of load,the axial force at the same position of pile body in nine-pile foundation generally shows the law that the corner pile is larger than the side pile and larger than the centre pile,but the trend of axial force decreasing along the pile body is different in piles of different positions;for the pile side resistance of group piles,the distribution of piles is basically the same,and in the late loading period,with the superposition of pile-soil mutual friction and the squeezing action of soil between piles,the maximum value of pile side resistance appears to be the same,and the maximum value of pile side resistance appears to be the same.In the late loading stage,with the superposition of pile-soil mutual friction and the crowding effect between the piles,the maximum value of pile-side friction resistance tends to move up.

关 键 词：群桩 竖向荷载 砂土地基 承载特性 模型试验 

分 类 号：TU473.1[建筑科学—结构工程]