摘要
灌注桩是最常见的桩基础形式之一,开展灌注桩桩身变形测量,对研究其桩身承载特性及分析桩身质量非常重要。采用目前国际上最为先进的光频域反射光纤传感技术(optical frequency domain reflectometer,OFDR),开展了灌注桩桩身变形高精度测量现场试验,获得了灌注桩在加载和卸载过程中的桩身变形、桩身轴力及桩身侧摩阻力分布情况,分析了加载和卸载过程中灌注桩桩身变形特征及荷载传递规律。试验结果表明:加载阶段光纤测得的桩身应变随荷载逐级增加,卸载阶段光纤测得的桩身应变随荷载逐级减小,卸载结束后桩身有一定应力残余;同时,通过对比加载、卸载过程中桩身轴力分布曲线,发现桩身轴力在卸载后存在时间滞后效应;结果显示OFDR技术能够实现对灌注桩桩身变形的高精度测量,并能精细化掌握桩身变形特征。
The cast-in-place pile is one of the most common forms of pile foundation.It is very important to conduct the measurement of pile deformation of the cast-in-place pile,which is of great use for understanding the bearing characteristics and quality of the pile.In this paper,optical frequency domain reflectometer(OFDR) is introduced as the most advanced technology in the world to carry out the field test on the high-precision measurement of deformation of the cast-in-place pile.During the test,the pile deformation,pile axial force and pile side friction distribution are obtained in the loading and unloading process.Simultaneously,the pile deformation characteristics and load transfer law are analyzed.The test results show that the strain of pile measured by the optical fiber sensor increases with the loading during the loading phase and decreases during the unloading phase,the pile has a certain residual stress after the unloading,however.Besides,through comparison of the pile force distribution curve in the loading and unloading process,it is found that the pile force has a time lag effect after unloading;the results prove that OFDR technology can achieve the high-precision measurement of pile deformation of the cast-in-place pile,which can be applied to investigate the pile deformation characteristics.
作者
高磊
周乐
刘汉龙
黄坚
王洋
韩川
GAO Lei;ZHOU Le;LIU Han-long;HUANG Jian;WANG Yang;HAN Chuan(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing,Jiangsu 210024,China;Key Laboratory of New Technology for Construction of Cities in Mountain Area,Chongqing University,Chongqing 400045,China;Shanghai Geological and Mining Engineering Survey Institute,Shanghai 200072,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2021年第7期2004-2014,共11页
Rock and Soil Mechanics
基金
国家自然科学基金项目资助(No.52027812)
中央高校基本科研业务费专项资金资助(No.B210202047)
江苏省研究生科研与实践创新计划项目(No.B200203202)。
关键词
灌注桩
桩身变形
OFDR分布式光纤监测
高精度
空间分辨率
cast-in-place pile
pile deformation
OFDR distributed optical fiber monitoring
high precision
spatial resolution
