摘要
为验证测温法在复杂孔内温度场景下早期识别混凝土灌注桩桩身缺陷的可行性,设计并制作含预制缺陷的灌注桩,分析桩身水化温度的时空分布特征,对试验数据分析方法进行研究,并对比测温法与声测法的检测效能和方法特征。结果表明:混凝土浇筑初期,缺陷区域呈现显著温度突变,但随水化进程推进,该特征逐渐减弱。现有的有效半径判别方法易受孔内温度场干扰,导致缺陷识别精度较低。基于混凝土灌注桩的水化热特性,提出了温度梯度平方判别方法与温度滑动方差判别方法2种基于数据统计特征的判别方法,能有效规避孔内温度干扰,可在水化温度达到峰值前识别出桩身缺陷。温度梯度平方判别方法可识别距温度测线0.8 m内超60%的缺陷,温度滑动方差判别方法在0.739 m内识别率达60%,缺陷识别率可优化测线布置,提升缺陷检测的准确性与效率。测温法与声测法均能准确识别出桩身缺陷,但测温法时效性更优,且无需声测管预埋与注浆等复杂工序。
This study investigates the applicability of thermal integrity profiling(TIP)in identifying early defects of bored piles in boreholes with complex thermal environments.Bored piles with intentionally created defects were designed and prepared,to analyze the temporal and spatial distribution characteristics of temperature in the pile.The test data analysis approaches were studied,and the efficiency and properties of the TIP and crosshole sonic logging(CSL)were compared.The results demonstrate that at the early concrete pouring stage,drastic temperature variation would be observed in the zones with defects,but as the hydration process advances,the temperature variation gradually weakens.The effective radius detection method is sensitive to the temperature field in the borehole,resulting in lowered defect identification accuracy.Based on the hydration heat characteristics of the bored piles,a defect identification method that integrates the data statistical characteristics of two methods,including the squared temperature gradient detection method and the temperature sliding variance detection method,is proposed,which can effectively avoid the temperature disturbance in the borehole and identify the pile defects before the hydration temperature reaches the peak.The squared temperature gradient detection method can identify over 60%of the defects within the zones 0.8 m to the temperature measurement line,while the temperature sliding variance detection method can identify 60%of the defects within the zones 0.739 m to the temperature measurement line,the defect identification rate can be used to optimize the layout of the temperature measurement lines,in turn to improve the accuracy and efficiency of defect detection.Both the TIP and CSL can identify the defects in the pile,but the TIP exhibits greater efficiency and necessitates no pre-embedded acoustic pipes and grouting.
作者
马远刚
何成园
马啸
黄锐
高国辉
MA Yuangang;HE Chengyuan;MA Xiao;HUANG Rui;GAO Guohui(State Key Laboratory of Bridge Intelligent and Green Construction,Wuhan 430034,China;China Railway Bridge Science Research Institute,Ltd.,Wuhan 430034,China)
出处
《世界桥梁》
北大核心
2025年第5期119-127,共9页
World Bridges
关键词
桥梁工程
灌注桩
基桩完整性检测
测温法
热异常
缺陷早期识别
水化热
声测法
bridge engineering
bored pile
pile intactness detection
thermal integrity profiling
heat anomaly
early defect identification
hydration heat
crosshole sonic logging
