Research On The Propagation Characteristics Of High-Frequency Ultrasonic Guided Wave In Grouted Rock Bolt Structure System

In recent years, anchoring technique in domestic and international engineering is widely used. But there is not very scientific and effective methods for the detection of anchoring quality,the traditional pull-out test and over-coring test are destructive and can not be promoted on the large scale. So people use non-destructive testing method to test the quality of anchor bolt,ultrasonic guided wave method as a new field of non-destructive testing method is applied to non-destructive testing of the anchoring quality. This paper is based on the theory of ultrasonic guided waves and reveals propagation rule and characteristics of the ultrasonic guided wave in the anchor bolt and free bolt through the large number of experiments and data analysis, the research laid the foundation for using the ultrasonic guided wave to test the quality of anchor bolt in practical engineering.The research work includes the following aspects:Firstly, traditional testing methods and non-destructive testing methods for the detection of anchoring quality were introduced, compared and analyzed,the author described the advantages of ultrasonic guided wave method in detail.Secondly,the concept of ultrasonic guided waves and propagation characteristics and rule of high-frequency ultrasonic guided waves in the free bolt and anchor bolt were introduced.Thirdly,using the center frequency of 2.25MHz ultrasonic sensor to research the anchor bolt of during and after the anchor period by high-frequency experimental device,the speed and attenuation of guided wave were analyzed by the experimental data, there are two methods for attenuation analysis:the peak ratio method and average amplitude ratio method, this paper finally gets the method of using high-frequency ultrasonic guided wave to test effective anchor length and the degree of grouting compaction of the anchor bolt.Finally, we make the application interface of testing effective anchor length and the degree of grouting compaction of the anchor bolt with the Matlab's GUI, the interface can automatically record and analyze the ultrasonic guided wave data and we can get the effective anchor length and the degree of grouting compaction of the anchor bolt.