超声导波技术在埋地锚杆检测中的应用研究

分析了超声导波在埋地锚杆中传播的特性。在理论上,对于埋地锚杆,40～90kHz的L(0,1)模态的衰减值在所有模态中最小,传播距离最长;位移模式简单,易于激发;能量速度最大,容易与其他速度较慢模态区别。此段L(0,1)模态可用来对埋地锚杆进行检测。同时建立实验系统,对直径22mm、长2m的埋地锚杆进行检测,实验结果与理论分析相吻合。

Application of ultrasonic guided waves technology to inspection of bolt embedded in soils

Propagation characteristics of longitudinal modes of bolt embedded in soils were studied.The attenuation of longitudinal mode L(0,1) at a range of frequency from 40 kHz to 90 kHz was the smallest in all modes.Its energy velocity was the fastest.And its profile of displacement was simple,which made it to be excited easily.It was indicated that longitudinal mode L(0,1) could be used in the inspection of bolt embedded in soil because it could propagate longer distance in the bolt and be distinguished from other modes with slow energy velocity.At the same time,the experiments with bolts 22 mm in diameter,2 m in length embedded in soils detected using ultrasonic guided waves were carried out.It was shown that longitudinal mode L(0,1) between 40 kHz and 90 kHz was suitable for the inspection of length and construction quality of bolt embedded in soils.