20～1000kHz超声导波用于锚杆锚固质量检测的探索

Discussion on 20～1 000 kHz Ultrasonic Guided Wave in the Anchoring Quality Inspection

为使超声波无损检测技术应用于锚杆锚固质量的检测，采用理论分析和实验室测试的方法对超声导波在锚杆中的传播规律进行了研究。在20—1000kHz导波频率范围内，对不同锚固质量的锚固锚杆进行了扫频，并根据实验结果得出了群速度随频率变化曲线。研究结果表明：频率较低时，同一频率导波在不同锚固质量的锚杆传播的群速度不一样，可用于锚杆锚固质量的检测；频率较高时，它们的群速度几乎一致，可用来检测锚固锚杆的长度，但存在一些可用于锚杆锚固质量检测的导波。

In order to apply the technology of Ultrasonic NDT in the Anchoring quality testing, this paper did a re- search in the propagation of the Guided wave in the bolt, using the method of theoretical analysis and laboratory testing. In 20--1 000 kHz guided wave frequency range, the quality of different anchoring bolt were swept, and the group velocity vs. frequency was obtained according to the experimental results. The research shows that, at lower frequency, the group ve- locity of the same frequency guided wave is not the same in the different quality anchor bolt propagation, and it can be used for the anchoring quality testing; while at higher frequencies, their group velocity is almost the same, and it can be used to detect the length of the anchor bolt. But there exists some guided wave that can test anchoring quality.