基于BOTDA的砂土地基预应力管桩抗拔静载试验研究  

Investigation of prestressed pipe piles uplift static load test on sandy ground using BOTDA technique

作　　者：孔洋 汪璋淳[1] 何宁[1,2] 何斌 张中流[1] 周彦章 KONG Yang;WANG Zhangchun;HE Ning;HE Bin;ZHANG Zhongliu;ZHOU Yanzhang(Nanjing Hydraulic Research Institute,Nanjing 210029,China;Key Laboratory of Reservoir Dam Safety of the Ministry of Water Resources,Nanjing 210029,China)

机构地区：[1]南京水利科学研究院,江苏南京210029 [2]水利部水库大坝安全重点实验室,江苏南京210029

出　　处：《水利水运工程学报》2024年第1期149-155,共7页Hydro-Science and Engineering

基　　金：国家重点研发计划资助项目(2021YFC3000103);国家自然科学基金长江水科学研究联合基金项目(U2240221);中央级公益性科研院所基本科研业务费专项资金资助项目(Y321003,Y320013)。

摘　　要：针对砂土地基抗拔桩受力性能与荷载传递机理研究不足问题,将布里渊光时域分析(BOTDA)光纤传感技术应用于长江下游地区厚层砂土地基预应力管桩原位抗拔静载试验研究,采用特殊设计的桩身刻槽钻孔、光纤粘贴保护、接桩过程连续植纤等技术工艺,实现了预应力管桩在拉拔过程中桩身受力变形状态的分布式测量与数据精确定位。研究结果表明:在上拔荷载作用下,试验桩桩身轴力沿桩身方向逐渐减小;桩侧摩阻力在下桩发挥效果较好,上桩侧摩阻力较小,全桩长侧摩阻力最大值在桩底;抗拔桩随上拔荷载的增加,轴力逐渐向下传递,向下传递的轴力主要由预制管桩侧摩阻力承担;分布式光纤应变传感技术能较好地监测预应力管桩桩身贯入施工因素对抗拔承载特性的影响。研究结果可在其他类型抗拔桩受力特性监测项目中推广应用。Due to limited research on the mechanical behavior and load transfer mechanism of uplift piles on sandy ground,the Brillouin optical time domain analysis(BOTDA)fiber optic sensing technology is utilized in the field testing of prestressed pipe piles on thick sand ground in the lower region of the Yangtze River.This involves employing specialized techniques such as grooving drilling of the pile body,protective measures for attaching optical fibers,and continuous fiber installation during pile connection.These processes enable distributed measurements and accurate data positioning of stress and deformation in the prestressed pipe pile during the uplift process.The study findings indicate a gradual decrease in axial force along the length of the test pile under the uplift load.The soil resistance on the sides of the pile exhibits effective support in the lower portion,while the upper section experiences less soil resistance.The maximum soil resistance is observed at the bottom of the pile.As the uplift load increases,the axial force gradually transfers downward,predominantly relying on the soil resistance of the prefabricated pipe pile.The use of distributed optical fiber strain sensing technology allows for better monitoring of the impact of construction factors on the uplift bearing characteristics during the penetration of prestressed pipe piles.These research results can be applied to other monitoring projects involving different types of uplift pile bearing characteristics.

关 键 词：BOTDA 抗拔桩 分布式光纤 静载试验 砂土地基 

分 类 号：TU473.16[建筑科学—结构工程] TU413.6[建筑科学—土工工程]