竖向荷载作用下挤扩支盘桩桩周土体位移场变化规律研究  

Research on soil displacement field around the squeezed branch pile under vertical load

作　　者：张敏霞[1] 崔文杰[1] 徐平[1] 牛月君 

机构地区：[1]河南理工大学土木工程学院,河南焦作454003

出　　处：《岩石力学与工程学报》2017年第A01期3569-3577,共9页Chinese Journal of Rock Mechanics and Engineering

基　　金：河南省高等学校深部矿井建设重点学科开放实验室开放基金(2014KF–07);国家自然科学基金资助项目(U1404527;51508166)~~

摘　　要：挤扩支盘桩桩周土体位移变化将直接影响其竖向承载力特性,然而常规试验手段下很难获取其桩周土体的变形特性。因此,采用基于透明土材料和粒子图像测速(particle image velocimetry,简称PIV)技术的桩基透明土模型试验系统,对轴向荷载作用下支盘桩和等截面桩桩周土体变形进行非介入式测量,得到桩周土体完整的变形位移场。试验结果表明,与等截面桩相比,支盘桩通过增大桩周土体变形位移场的范围,减小了土体变形位移场的强度,从而提高了桩基承载能力;支盘与桩端土体位移场均具有放射状的特征,表明支盘与桩端承载机制一致,支盘承担部分桩顶荷载,改变了荷载传递规律;支盘处土体位移场特征表明,支盘下界面土体位移变形对桩侧摩阻力的发挥产生了消极影响;试验还发现支盘位置、间距对桩周土体位移场的影响较大,支盘间距取值宜大于三倍支盘直径。Displacement changes of the soil around the squeezed branch pile directly affect its vertical bearing capacity, while, traditional test methods are different to obtain the deformation characteristics of soil around the pile. The transparent soil model test was carried out, which is based on transparent materials and particle image velocimetry（referred to as PIV） technique, and the soil displacement around the branch pile and soil around equal section pile under axial load are tested by non-intrusive measurement. Test results show： compared with the equal section pile, squeezed branch pile can increase the bearing capacity by increasing the scope of the soil deformation displacement field and inducing the strength of the soil deformation displacement field. The soil displacement around the branches and that under the pile tip both have radial features, which shows the branch and the pile tip have the same bearing capacity, and the branches share a part of the pile load and change load transfer law. According to the soil displacement field around the branch, the soil displacement under the branch has a negative effect on the lateral frictional resistance of the pile. The position and distance of the branches have a great influence on the soil displacement field of around the branch pile through the test, and the distance between the branches should better be more than three times of the branch diameter.

关 键 词：桩基础 支盘桩 透明土 模型试验 土体位移场 

分 类 号：TU473[建筑科学—结构工程]