An Analysis of Rock Bolt Dynamic Responses to Evaluate the Anchoring Degree of Fixation
Rock bolting in underground environments is used for different fundamental reasons, including suspending potentially loosened blocks, clamping small wedges together, inducing a protective pressure arch along the contour of excavated voids to improve the self-supporting capacity of the ground, and pr...
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MDPI AG
2025-02-01
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| author | Alberto Godio Claudio Oggeri Jacopo Seccatore |
| author_facet | Alberto Godio Claudio Oggeri Jacopo Seccatore |
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| description | Rock bolting in underground environments is used for different fundamental reasons, including suspending potentially loosened blocks, clamping small wedges together, inducing a protective pressure arch along the contour of excavated voids to improve the self-supporting capacity of the ground, and providing passive pressure in integrated support systems. In this study, we describe a testing procedure that was developed to investigate the grouted annulus of a rock bolt using a low-cost investigation method. This diagnostic technique was based on the dynamic response of the system, where mechanical vibrations were induced within the rock bolt and the response was recorded by using geophones/accelerometers on the protruding element of the bolt (the collar and head). The collected signal was then processed to estimate the spectral response, and the amplitude spectrum was analyzed to detect the resonance frequencies. A 3D finite element model of the rock bolt and grouting was established to simulate the quality of the coupling by varying the mechanical properties of the grouting. The model’s response for the studied geometry of the rock bolt suggested that a poor quality of grouting was usually associated with flexural modes of vibration with a low resonance frequency. Good-quality grouting was associated with a frequency higher than 1400 Hz, where the axial vibration was mainly excited. Our analyses referred to short rock bolts, which are usually adopted in small tunnels. The interpretation of the experimental measurements assumed that the spectral response was significantly affected by the quality of the grouting, as demonstrated by the modeling procedure. The resonant frequency was compared with the results of the model simulation. The method was used to test the quality of rock bolts in a small experimental tunnel carved from andesite rock in Chile. Low-cost shock sensors (piezoelectric geophones) with low sensitivity but a wide frequency band were used. The main research outcome was the development of a reliable method to model the dynamic response of rock bolts in mines or for experimental applications in tunnels. Albeit limited to the current specific geometries, the modeling and testing will be adapted to other anchor/bolt options. |
| format | Article |
| id | doaj-art-22cd4e10f1c94099af1dd01d971f0b33 |
| institution | OA Journals |
| issn | 2076-3417 |
| language | English |
| publishDate | 2025-02-01 |
| publisher | MDPI AG |
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| series | Applied Sciences |
| spelling | doaj-art-22cd4e10f1c94099af1dd01d971f0b332025-08-20T02:12:38ZengMDPI AGApplied Sciences2076-34172025-02-01153151310.3390/app15031513An Analysis of Rock Bolt Dynamic Responses to Evaluate the Anchoring Degree of FixationAlberto Godio0Claudio Oggeri1Jacopo Seccatore2DIATI, Politecnico di Torino, 10128 Torino, ItalyDIATI, Politecnico di Torino, 10128 Torino, ItalyDepartment of Metallurgical and Mining Engineering, Universidad Católica del Norte, Antofagasta 1240000, ChileRock bolting in underground environments is used for different fundamental reasons, including suspending potentially loosened blocks, clamping small wedges together, inducing a protective pressure arch along the contour of excavated voids to improve the self-supporting capacity of the ground, and providing passive pressure in integrated support systems. In this study, we describe a testing procedure that was developed to investigate the grouted annulus of a rock bolt using a low-cost investigation method. This diagnostic technique was based on the dynamic response of the system, where mechanical vibrations were induced within the rock bolt and the response was recorded by using geophones/accelerometers on the protruding element of the bolt (the collar and head). The collected signal was then processed to estimate the spectral response, and the amplitude spectrum was analyzed to detect the resonance frequencies. A 3D finite element model of the rock bolt and grouting was established to simulate the quality of the coupling by varying the mechanical properties of the grouting. The model’s response for the studied geometry of the rock bolt suggested that a poor quality of grouting was usually associated with flexural modes of vibration with a low resonance frequency. Good-quality grouting was associated with a frequency higher than 1400 Hz, where the axial vibration was mainly excited. Our analyses referred to short rock bolts, which are usually adopted in small tunnels. The interpretation of the experimental measurements assumed that the spectral response was significantly affected by the quality of the grouting, as demonstrated by the modeling procedure. The resonant frequency was compared with the results of the model simulation. The method was used to test the quality of rock bolts in a small experimental tunnel carved from andesite rock in Chile. Low-cost shock sensors (piezoelectric geophones) with low sensitivity but a wide frequency band were used. The main research outcome was the development of a reliable method to model the dynamic response of rock bolts in mines or for experimental applications in tunnels. Albeit limited to the current specific geometries, the modeling and testing will be adapted to other anchor/bolt options.https://www.mdpi.com/2076-3417/15/3/1513rock boltsgroutingmodal analysissupport systemanchoring |
| spellingShingle | Alberto Godio Claudio Oggeri Jacopo Seccatore An Analysis of Rock Bolt Dynamic Responses to Evaluate the Anchoring Degree of Fixation Applied Sciences rock bolts grouting modal analysis support system anchoring |
| title | An Analysis of Rock Bolt Dynamic Responses to Evaluate the Anchoring Degree of Fixation |
| title_full | An Analysis of Rock Bolt Dynamic Responses to Evaluate the Anchoring Degree of Fixation |
| title_fullStr | An Analysis of Rock Bolt Dynamic Responses to Evaluate the Anchoring Degree of Fixation |
| title_full_unstemmed | An Analysis of Rock Bolt Dynamic Responses to Evaluate the Anchoring Degree of Fixation |
| title_short | An Analysis of Rock Bolt Dynamic Responses to Evaluate the Anchoring Degree of Fixation |
| title_sort | analysis of rock bolt dynamic responses to evaluate the anchoring degree of fixation |
| topic | rock bolts grouting modal analysis support system anchoring |
| url | https://www.mdpi.com/2076-3417/15/3/1513 |
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