Non-Destructive Evaluation of Rock Bolt Grouting Quality by Analysis of Its Natural Frequencies

Grouted rock bolts represent one of the most used elements for rock mass stabilization and reinforcement and the grouting quality has a crucial role in the load transfer mechanism. At the same time, the grouting quality as well as the grouting procedures are the least controlled in practice. This pa...

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Bibliographic Details
Published in:Materials 2020-01, Vol.13 (2), p.282
Main Authors: Bačić, Mario, Kovačević, Meho Saša, Kaćunić, Danijela Jurić
Format: Article
Language:English
Subjects:
Design
Failure
Finite element method
Grout
Grouting
Laboratories
Load transfer
Methods
Nondestructive testing
Numerical models
Resonant frequencies
Rock bolts
Rock masses
Shear strength
Statistical analysis
Stiffness
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Summary:Grouted rock bolts represent one of the most used elements for rock mass stabilization and reinforcement and the grouting quality has a crucial role in the load transfer mechanism. At the same time, the grouting quality as well as the grouting procedures are the least controlled in practice. This paper deals with the non-destructive investigation of grouting percentage through an analysis of the rock bolt's natural frequencies after applying an artificial longitudinal impulse to its head by using a soft-steel hammer as a generator. A series of laboratory models, with different positions and percentages of the grouted section, simulating grouting defects, were tested. A comprehensive statistical analysis was conducted and a high correlation between the grouting percentage and the first three natural frequencies of rock bolt models has been established. After validation of FEM numerical models based on experimentally obtained values, a further analysis includes consideration of grout stiffness variation and its impact on natural frequencies of rock bolt.
ISSN:1996-1944
1996-1944
DOI:10.3390/ma13020282