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

发布时间：2018-03-25 09:44

本文选题：桩基础　切入点：支盘桩　出处：《岩石力学与工程学报》2017年S1期

【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。
[Abstract]:The displacement change of soil around the pile will directly affect the vertical bearing capacity of the pile, but it is difficult to obtain the deformation characteristics of the soil around the pile by conventional test methods. Based on transparent soil material and particle image velocimetric (particle image velocimetric) technique, a model test system of transparent soil for pile foundation was developed to measure the soil deformation around the pile under axial load. The experimental results show that compared with the equal-section pile, the branch and disc pile reduces the strength of the soil deformation displacement field by increasing the range of the soil deformation displacement field around the pile, and thus improves the bearing capacity of the pile foundation. The displacement field of the soil mass at the branch and pile ends has radial characteristics, which indicates that the bearing mechanism of the branch disk is the same as that of the pile end, and the branch plate bears part of the load on the top of the pile, which changes the law of load transfer, and the characteristics of the soil displacement field at the branch plate show that, It is found that the position and spacing of the branches have a great influence on the displacement field of the soil around the pile, and the spacing between the branches and disks should be more than three times the diameter of the branches.
【作者单位】：河南理工大学土木工程学院;
【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)~~
【分类号】：TU473.1

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