| Recently, the technology of metal bar bonding is used abroad in the engineering field. But how to adopt an effective method to test anchoring quality has not been resolved yet. If anchoring capability is lost, huge potential damage of project is brought. The traditional pullout test may destruct metal bar and can't meet the need of anchoring quality test on a large scale. Thus, researching and applying a new test for the quality of rock bolt bonding is an important task in the rock-soil field. Given the slender and cylindrical structure of a rock bolt, guided waves as opposed to the conventional ultrasonic waves are excited in a rock bolt. The characteristics of the guided wave propagating along rock bolts are affected by the length of rock bolts, structure of the grout and quality of grouted material. A lot of research has been done based on the study of the ultrasonic guided wave propagation theory. The research laid the foundation which is using the ultrasonic guided wave to the quality engineering detection of bolts. Contents have shown that:Firstly, the author investigated the right projects and the practical application of their quality and safety, and described the future of Ultrasonic guided wave detection in the bolts.Secondly, we can see frequency of the signal change over time and find the valid signal accurately by using the empirical mode decomposition and Hilbert Huang Transform method. Besides, the signal processing will be more precise when using energy method to measure energy of the wavelet packet.Thirdly, the author finds a simple and practical method which can test the effective anchor length accurately by using high-frequency guided wave.Finally, based on the attenuate theory of guided wave, we find that the degree of grouting compaction of bolt bonding has relation with the peak ratio of two receiving wavelet packet. We can detect the degree of grouting compaction of bolt bonding by using the ratio. |
