Non-destructive inspection on anchorage defect of hollow grouted rock bolt using wavelet transform analysis

Yang, Hao; Yu, Wu; Li, Pan; Tao, Jing; Teng, Yi; Guan, Hao

doi:10.1186/s13640-018-0385-4

Cited by 11 publications

(4 citation statements)

References 19 publications

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“…Yang Hao used the hammer method and wavelet transform analysis to detect grouting defects in rock bolts. The analysis results certified that nondestructive detecting technology can be used to easily distinguish the free length, the grouted length, the defect length, and their respective positions [8]. Fei Yao detected the grouting defects in segment-grout structures through the impact-echo method.…”

Section: Introductionmentioning

confidence: 70%

Detection of sleeve grouting connection defects in fabricated structural joints based on ultrasonic guided waves

Liu

2019

Smart Mater. Struct.

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Sleeve grouting is widely used for connecting prefabricated building components. Grouting defects have become an important factor affecting the application of grout sleeves. However, there is still a lack of monitoring methods for grouting defects in grout sleeves. In this paper, the ultrasonic guided wave method is used to detect grouting defects in the grout sleeve. The influence of the grouting defects on the guided wave signal is studied through experiments and simulations. Based on the differences between the guided wave signals of a healthy specimen and defective specimens, damage index values are proposed. The relation between the damage indexes and the mechanical properties is established via grouting sleeve monotonic tensile tests. The idea of using the analytic hierarchy process to complete a structural health evaluation is advanced. Both the experimental results and the simulated results show that there is relevance between the damage index and grouting defects. When the defect increases, the damage index value will increase significantly. The ultrasonic guided waves can effectively detect grouting defects in grout sleeves.

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Section: Introductionmentioning

confidence: 70%

Detection of sleeve grouting connection defects in fabricated structural joints based on ultrasonic guided waves

Liu

2019

Smart Mater. Struct.

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“…To mitigate the influence of environmental and equipment noise on the detection results, several signal processing methods have been proposed for anchor rods NDT. These methods include Fourier transform (FFT) [3], wavelet filtering [4,5], variational mode decomposition-Hilbert Huang transform (VMD-HHT) [6], empirical mode decompositionspectral kurtosis denoising [7], HHT [8], AILPSA [9], grey cloud model [10], etc. Among them, FFT and wavelet filtering are earlier and widely applied signal processing methods.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the dynamic characteristics of anchor rods considering size effect and pull-out loads based on IIR-FDM

Sun,

Zhu,

Song

et al. 2024

Meas. Sci. Technol.

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When the surrounding rock of tunnel anchor bars has boundaries, the signals obtained from NDT of anchor rods will be simultaneously affected by size effects and pull-out loads, leading to potential misinterpretation of the test results. In order to accurately assess the anchorage quality of anchor rods under this interference, NDT and numerical simulations of anchor rods subjected to different anchorage quality were conducted under the influence of size effects and pull-out loads. A signal filtering method, which combines the infinite impulse response-finite difference method , was proposed for identify the impact of size effects. The study analyzed the variations in wave velocity and fundamental frequency of anchor rods with anchorage defects and intact anchor rods under the influence of size effects and pull-out loads. The results indicate that the IIR-FDM method, in comparison to the traditional wavelet method, provides better agreement between the calculated wave velocities and existing findings. With the increase of size effect, the wave velocity and amplitude ratio of the anchor rods decrease, and the fundamental frequency increases first and then decreases. As the working load on the anchor rods increases, the wave velocity initially decreases, then rises, while the fundamental frequency initially increases and then experiences a slight decrease. The presence of anchorage defect results in an increase in the wave velocity and amplitude ratio of the anchor rods, while causing a decrease in the fundamental frequency. This effect of defects on wave velocity and fundamental frequency is more pronounced at lower loads. The wave velocity after IIR-FDM processing has a small error with the simulated wave velocity, indicating the reliability of the processing method.

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“…In a diagnosis process both acoustic and ultrasonic waves are utilized. Correspondingly, different analytical approaches are used as Fast Fourier Transform (FFT), wavelet transform analysis and neural network algorithms (Beard and Lowe 2003;Starkey et al 2003;Hao et al 2018;Patil and Maiti 2005;Sadettin 2007;Hyett et al 2012). In order to observe the behavior of grouted rock bolts also smart sensors techniques are introduced (Gangbing et al 2017), in particular load measurements at the heads (Hyett et al 2012).…”

Section: Introductionmentioning

confidence: 99%

Technical problems and non destructive testing of rock bolt support systems in mines

Staniek

2023

Int J Coal Sci Technol

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The problem of proper assessment of the technical functionality of rock bolt support systems is still valid. Many research centers have undertaken efforts to diagnose and monitor the technical state of such a support system used in mines and tunneling. With that aim the method of quality assessment of grouted rock bolts was invented and a relevant apparatus was constructed. The method concerns non-destructive identification of discontinuity of a resin layer (grout) surrounding rock bolts. The method is based on an impact excitation of a rock bolt and uses modal analysis procedures. Assuming that the installed rock bolt acts as an oscillator, different lengths and positions of grouting discontinuity alter its modal parameters. The extraction of these modal parameters, of which a resonant frequency is seen as the most valued, enable the relevant identification of grout discontinuity. After constructing a prototype version and validating the results for known cases of resin discontinuity in an experimental coal mine, the apparatus fulfilling ATEX requirements was developed. Subsequently that version was also verified both in laboratory conditions and in an experimental coal mine. As necessary for proper identification of discontinuity length, the reference data base was developed and elaborated consisting of a very large number of finite element models (FE models), namely discontinuity cases. The models encountered different rock bolt lengths and diameters, different rock strata parameters and different positions and lengths of resin layers. Then the method was used in a working coal mine to monitor a technical state of rock bolt support system mounted to reinforce long underground openings. The data base was utilized as reference for investigated rock bolts.

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Non-destructive inspection on anchorage defect of hollow grouted rock bolt using wavelet transform analysis

Cited by 11 publications

References 19 publications

Detection of sleeve grouting connection defects in fabricated structural joints based on ultrasonic guided waves

Detection of sleeve grouting connection defects in fabricated structural joints based on ultrasonic guided waves

Investigation on the dynamic characteristics of anchor rods considering size effect and pull-out loads based on IIR-FDM

Technical problems and non destructive testing of rock bolt support systems in mines

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