Integrity evaluation of grouted rock bolts using reflected guided ultrasonic waves

Jong-Sub Lee, Jung Doung Yu, Myeong Ho Bae, Shin In Han, Yong Jun Lee, In Mo Lee

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

As one of the main support systems in the reinforcement of underground structures and rock slopes, rock bolts have been commonly used. Destructive pull out tests have been used to investigate the integrity of the rock bolts. Furthermore, a non-destructive technique using transmitted guided ultrasonic waves was suggested. Note for the transmission method, the source of the ultrasonic waves should be installed on the end of the steel bar during construction of the rock bolts in the field. The purpose of this paper is to suggest a reflection method using guided ultrasonic waves to evaluate the integrity of the grouted rock bolts in the laboratory. Steel bar with 3.1m in length and 25.4mm in diameter are grouted with different defect ratio ranging 0-100%. The diameter of the cement grouting is 38mm. The guided waves are generated by PZT element. The reflected guided waves are measured by AE sensor at the end of the grouted rock bolt. The wavelet transform is used to calculate the energy velocities of the reflected guided waves. The results show that the energy velocities of reflected guided ultrasonic waves increase with the defect ratio. Furthermore, the velocities calculated by the reflection method are similar to velocities by the transmission method. This research demonstrates that the reflection method for the rock bolt integrity may be effective method for the integrity evaluation of the grouted rock bolts.

Original languageEnglish
Title of host publication15th International Congress on Sound and Vibration 2008, ICSV 2008
Pages1267-1274
Number of pages8
Volume2
Publication statusPublished - 2008 Dec 1
Event15th International Congress on Sound and Vibration 2008, ICSV 2008 - Daejeon, Korea, Republic of
Duration: 2008 Jul 62008 Jul 10

Other

Other15th International Congress on Sound and Vibration 2008, ICSV 2008
CountryKorea, Republic of
CityDaejeon
Period08/7/608/7/10

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ASJC Scopus subject areas

  • Acoustics and Ultrasonics

Cite this

Lee, J-S., Yu, J. D., Bae, M. H., Han, S. I., Lee, Y. J., & Lee, I. M. (2008). Integrity evaluation of grouted rock bolts using reflected guided ultrasonic waves. In 15th International Congress on Sound and Vibration 2008, ICSV 2008 (Vol. 2, pp. 1267-1274)