摘要
跨孔弹性波CT技术是岩溶地层勘察的重要物探方法,该方法用于既有桩基缺陷探测的研究较少。本文提出一种基于跨孔弹性波CT测试的既有桩基无损检测方法,选取某缺陷桩基开展跨孔弹性波CT法与其他无损方法的对比测试,并依托某桥梁事故案例进行该方法的应用研究,明确了该方法用于桩身缺陷探测的有效性。研究结果表明:桩基跨孔弹性波CT法反演的速度剖面能基本反映桩基水平受荷变形与缺陷情况,直观呈现桩身内部与周围岩土体的波速分布,实现不同方位和高覆盖率的桩身缺陷探测;该方法对桩身混凝土环向贯通裂隙、浇筑质量缺陷均具有较好的识别能力,但难以进一步判别低速区桩身缺陷的类别;该方法对摩擦桩桩端位置和嵌岩桩入岩位置具有良好的判别能力,但较难准确判别嵌岩桩的入岩深度。
The cross-hole elastic wave computerized tomography(CT)technique is an important geophysical method to investigate karst formations,but its application in the study of existing pile defects is still limited.This paper proposes a non-destructive testing method for existing piles based on cross-hole elastic wave CT.A comparative test is conducted on a pile with known defects using the cross-hole elastic wave CT method and other non-destructive methods.The application of this method is further investigated through a case study of a bridge accident,confirming its effectiveness in detecting pile defects.The study results indicate that the velocity profile inverted by the cross-hole elastic wave CT method can essentially reflect the horizontal deformation and defect conditions of the pile.It provides a visual representation of the wave velocity distribution in the pile and the surrounding rock and soil,enabling the detection of defects in the pile body with different orientations and high coverage rates.The method demonstrates good recognition capabilities for circumferential through cracks in the concrete of the pile and defects in concreting quality but faces challenges in further distinguishing the categories of defects in the low-velocity zone of the pile.The method exhibits good discrimination capabilities to identify the end position of friction piles and end-bearing piles,but it is a challenge to accurately determine the rock socketing length.
作者
杨军
孙晓立
谢礼安
李柯柯
王林彬
Yang Jun;Sun Xiaoli;Xie Lian;Li Keke;Wang Linbin(Guangzhou Municipal Engineering Testing Co.,Ltd.,Guangzhou 510520,China;Guangdong Provincial Engineering Research Center for Assembled Underground Structure Detection and Monitoring,Guangzhou 510520,China;School of Civil Engineering,Tsinghua University,Beijing 100084,China;Key Laboratory for Wind and Bridge Engineering of Hunan Province,College of Civil Engineering,Hunan University,Changsha 410082,China)
出处
《工程勘察》
2024年第11期81-86,共6页
Geotechnical Investigation & Surveying
基金
广东省住房和城乡建设厅2022年科技创新计划项目(2022-K26-503115)
广州市建筑集团有限公司科技计划项目([2021]-KJ052
[2021]-KJ054).
关键词
既有桩基
跨孔弹性波CT法
现场试验
无损检测
工程应用
existing pile foundation
cross-hole elastic wave CT method
non destructive testing
on site testing
engineering application
