Investigation on Methods of Determining the Grouting Quality of Embedded Rock Bolts Using High Frequency Guided Waves

Zhang, Changsuo; Yang, Guanlin

doi:10.1155/2021/6626062

Cited by 2 publications

(1 citation statement)

References 12 publications

(12 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When the surrounding rock boundaries are finite, the impedance at these boundaries causes stress waves reaching the boundaries to reflect. The lateral dimensions of the surrounding rock have an impact on the test results [9,25]. In such cases, the stress waves propagating in the anchorage system are similar to pile foundations, and under the influence of size effects, the peak of the bottom reflection signal is reduced, making it difficult to identify response peak at the defect [26,27].…”

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.

View full text Add to dashboard Cite

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.

show abstract