Research on non-destructive testing technology for bolt anchoring quality by using the stress wave method

Wu, Tongqing; Xu, N.; Zhao, Baoyun; Chen, Kui; Li, Chengfang

doi:10.1201/9781315116167-70

Cited by 1 publication

(1 citation statement)

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“…The wave velocities obtained at different filtering levels are presented in table 3. It can be observed that the wave velocities obtained from d4 and d5 exhibit significant differences when compared to the results calculated in existing literature [31][32][33]. In the case of d6, although the size of the wave velocity is consistent with the range of the existing literature, the size changes under the influence of the size effect are quite different [34][35][36].…”

Section: Methodssupporting

confidence: 64%

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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