循环拉荷载作用下桩基础承载性能分析  

Analysis of Bearing Capacity of Pile Foundation under Cyclic Tensile Load

作　　者：朱武卫 赵金朋 李哲[2] 刘路路 谢乐乐 Zhu Wuwei;Zhao Jinpeng;Li Zhe;Liu Lulu;Xie Lele(Shaanxi Academy of Building Science,Xian,710000,P.R.China;School of Highway,Changan University,Xian 710064,P.R.China;State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,P.R.China)

机构地区：[1]陕西省建筑科学研究院,西安710000 [2]长安大学公路学院,西安710064 [3]中国矿业大学深部岩土力学与地下工程国家重点试验,江苏徐州221116

出　　处：《地下空间与工程学报》2024年第6期1944-1951,共8页Chinese Journal of Underground Space and Engineering

基　　金：江苏省卓越博士后计划(2022ZB529);江苏省自然科学基金青年项目(BK20221136)。

摘　　要：桩基础作为常见的承重基础,广泛应用于黄土地区。为了探明西北地区循环荷载下抗拔桩承载力特性,通过开展现场模型试验研究了3根不同工况的抗拔桩在不同循环荷载下的桩顶轴向位移和桩侧摩阻力性能,并对比了它们的差异性。结果表明:循环荷载作用下桩体破坏时桩顶轴向位移量只有常规加载的30%,桩顶轴向位移量与桩基承载能力具有强相关性;桩土本身在加载-卸载的过程中随着循环次数的增加桩土之间反复剪切发生屈服;常规桩基试验各层摩阻力强度弱化一般发生在极限荷载阶段,而循环加载后桩侧摩阻力强度弱化在极限荷载之前的循环过程中已经发生。研究结果可为桩基础的应用提供指导。Pile foundations are commonly employed as load-bearing structures in loess regions.This study sought to investigate the bearing capacity characteristics of cyclic uplift piles in the northwest region by conducting on-site model tests.These tests examined the axial displacement and lateral friction performance of uplift piles under three different working conditions and varying cyclic loads.The findings revealed that the axial displacement at the pile top during pile failure under cyclic loading was merely 30%of that observed under conventional loading.There exists a significant relationship between the axial displacement at the pile top and the bearing capacity of the pile foundation.During the loading-unloading process,the pile-soil interaction leads to yield as the number of cycles increases,signifying repeated shear between the pile and soil.While the decline in frictional resistance strength of each layer in conventional pile foundation tests typically manifests during the ultimate load stage,this weakening is observed during the cyclic process prior to reaching the ultimate load in cyclic loading conditions.These insights can inform the application of pile foundations.

关 键 词：桩基础 循环荷载 现场模型试验 桩顶位移 桩侧阻力 

分 类 号：TU473[建筑科学—结构工程]