兰州理工大学学报

兰州理工大学学报 ›› 2023, Vol. 49 ›› Issue (2): 130-137.

• 建筑科学 • 上一篇    下一篇

基坑开挖卸荷下桩基抗拔承载力影响因素研究

饶凯*1, 刘彦辉1, 王际凯2,3, 黄展军4, 罗如平2,3, 石钰锋2,3   

  1. 1.江西赣江中医药科创城建设投资集团有限公司, 江西 南昌 330000;
    2.江西省岩土工程基础设施安全与控制重点实验室, 华东交通大学,江西 南昌 330013;
    3.江西省地下空间技术开发工程研究中心, 华东交通大学, 江西 南昌 330013;
    4.南昌轨道交通集团有限公司, 江西 南昌 330038
  • 收稿日期:2021-12-14 出版日期:2023-04-28 发布日期:2023-05-05
  • 通讯作者: 饶 凯 (1985-),男,江西南昌人,高级工程师.Email:512797846@qq.com
  • 基金资助:
    江西省自然科学基金(20192ACB20001),国家杰出青年科学基金(51725802),国家自然科学基金-高铁联合基金(U1934208),南昌轨道交通集团科研项目(2019HGKYB002)

Study on influence factors of uplift pile bearing capacity under unloading of foundation pit excavation

RAO Kai1, LIU Yan-hui1, WANG Ji-kai2,3, HUANG Zhan-jun4, LUO Ru-ping2,3, SHI Yu-feng2,3   

  1. 1. Jiangxi Ganjiang Traditional Chinese Medicine Innovation City Construction Investment Group Co. Ltd., Nanchang 330000, China;
    2. School of Civil Engineering and Architecture, East China Jiaotong University, Nanchang 330013, China;
    3. Engineering Research & Development Centre for Underground Technology, East China Jiaotong University, Nanchang 330013, China;
    4. Nanchang Rail Transit Group Co. Ltd., Nanchang 330013, China
  • Received:2021-12-14 Online:2023-04-28 Published:2023-05-05

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摘要： 目前关于抗拔桩的研究多以桩侧摩阻力反映桩的承载性状,对于桩侧桩-土界面法向压力研究较少.鉴于此,采用Plaxis 3D有限元软件,研究基坑开挖后桩的极限抗拔承载力、桩侧摩阻力等的变化情况.结果表明:对桩承载力而言,桩周土体的粘聚力和摩擦角影响较大;开挖的范围对桩的承载力影响较小,粉质黏土中基坑开挖宽度大于37.5倍桩径时,较未开挖时承载力损失比值为10.82%~17.83%,而砂土中基坑开挖宽度大于40倍桩径时,较未开挖时承载力损失比值为15.37%~33.01%;对桩-土界面法向压力曲线进行线性拟合并与未开挖状态下的斜率进行归一化分析,得到开挖后斜率与未开挖状态下的斜率比值,粉质黏土为9.18,砂土为34.92~40.94.

关键词: 抗拔桩, 抗拔承载力, 基坑开挖, 桩-土界面法向压力

Abstract: At present, the research on uplift pile mainly uses pile side friction to reflect the bearing behavior of pile, and there is little research on the normal pressure of pile-soil interface. In view of this, through the PLAXIS 3D, the changes of pile ultimate uplift bearing capacity, pile side friction, pile shaft axial force and pile normal stress after foundation pit excavation were studied. The results show that: for the bearing capacity of pile, the influence of cohesion and friction angle of soil around pile is great; the excavation range has little impact on the bearing capacity characteristics of the pile, for silty clay, when the width of the foundation pit excavation is greater than 37.5 times the pile diameter, compared with the non excavation, the loss ratio of bearing capacity is 10.82%~17.83%; for sandy soil, when the width of the foundation pit excavation is greater than 40 times the pile diameter, compared with no excavation, the bearing capacity loss ratio is 15.37%~33.01%. Linear fitting on the normal pressure curve of the pile soil interface and normalization analysis on the slope in the unexcavated state were performed and the ratio of the slope after excavation to the slope in the unexcavated state was obtained, which is 9.18 for silty clay and 34.92~40.94 for sandy soil.

Key words: uplift pile, uplift capacity, foundation pit excavation, the normal pressure of pile-soil interface

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