Non-destructive inspection of ground anchors using guided wave propagation

Zima, Beata; Rucka, Magdalena

doi:10.1016/j.ijrmms.2017.03.005

Cited by 29 publications

(12 citation statements)

References 18 publications

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“…In both cases first reflection from the end of the specimen is registered in different times for perfect and imperfect rods. As was proved in papers [19], [20] and [26] when for the analyzed excitation frequency more than one wave mode can propagate, mode with the highest velocity is registered first. Usually, from the point of view of the diagnostic procedure, this reflection is the most important as reflection which is characterized by the high amplitude and is the easy to identify.…”

Section: Numerical Resultsmentioning

confidence: 57%

“…Out of consideration for readability dispersion curves were determined in limited frequency range 0-50 kHz. From the practical point of view, waves are usually excited in embedded metal waveguide and then are transmitted into surrounding medium [26]. In the case of eccentric location, waves are also excited non-centrally, what leads to excitation not only longitudinal modes, but also flexural modes.…”

Section: Dispersion Curvesmentioning

confidence: 99%

“…Since wave propagation velocity is usually a key parameter in diagnostics process, changes in wave velocities may lead to inaccurate estimation of those quantities that can be determined on the basis of time-of-flight (ToF) during nondestructive evaluation of two-layer rods i.e. bonding length or debonding length [19], [26]. To minimize the influence of eccentricity on the obtained results one can choose frequency which is insensitive to this kind of imperfections.…”

Section: Dispersion Curvesmentioning

confidence: 99%

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Numerical investigation of the core eccentricity effect on wave propagation in embedded waveguide

Zima¹,

Kędra²

2019

Diagnostyka

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The paper presents results of theoretical and numerical investigation of guided wave propagation in twolayer bars with geometric imperfections in the form of eccentric location of steel core. Steel rod of diameter equal to 1 cm embedded in composite mortar-type cover with external diameter equal to 5 cm has been taken into consideration. Several different rods with variable size of eccentricity are analysed. Results for rods with misalignment of the cover and the core are presented as dispersion curves which were calculated using SAFE method (semi-analytical finite element) and compared with results obtained for perfect axisymmetric rod. Moreover, numerical calculation for several cases of imperfect rods were conducted and results given in the form of displacements and accelerations maps and time-domain signals.

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Section: Numerical Resultsmentioning

confidence: 57%

Section: Dispersion Curvesmentioning

confidence: 99%

Section: Dispersion Curvesmentioning

confidence: 99%

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Numerical investigation of the core eccentricity effect on wave propagation in embedded waveguide

Zima¹,

Kędra²

2019

Diagnostyka

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“…The finite element software Abaqus (2014) has often been applied for numerical simulation of the debonding behaviors (Zima and Rucka 2017;Qiao and Chen 2008;Lu and Xu 2013;Chang et al 2017;Xu et al 2018;Chen et al 2011;Henriques et al 2013Henriques et al , 2015Yang et al 2017) and non-destructive testing Rucka 2017, 2018) of grouted rockbolt system. In this section, grouted rockbolt system were simulated by four-node bilinear axisymmetric quadrilateral elements with reduced integration (CAX4R) (Fig.…”

Section: Numerical Model Of Grouted Rockbolt Systemmentioning

confidence: 99%

Experimental and numerical evaluation on debonding of fully grouted rockbolt under pull-out loading

Zhu

Niu

2021

Preprint

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The axial loading in rockbolts changes due to stress redistribution and rheology in the country rock mass. Such a change may lead to debonding at rockbolt to grout interface or rupture of the rockbolt. In this study, based on laboratory experiments, ultrasonic guided wave propagation in fully grouted rockbolt under different pull-out loads was investigated in order to examine the resultant debonding of rockbolt. The signals obtained from the ultrasonic monitoring during the pull-out test were processed using wavelet multi-scale analysis and frequency spectrum analysis, the signal amplitude and the amplitude ratio (Q) of low frequency to high frequency were defined to quantify the debonding of rockbolt. In addition to the laboratory test, numerical simulation on the effect of the embedment lengths on ultrasonic guided wave propagation in rockbolt was conducted by using a damage-based model, and the debonding between rockbolt and cement mortar was numerically examined. It was confirmed that the ultrasonic guided wave propagation in rockbolt was very sensitive to the debonding because of pull-out load, therefore, the critical bond length could be calculated based on the propagation of guided wave in the grouted rockbolt. In time domain, the signal amplitude in rockbolt increased with pull-out load from 0 kN to 100 kN until the completely debonding, thus quantifying the debonding under the different pull-out loads. In the frequency domain, as the Q value increased, the debonding length of rockbolt decreased exponentially. The numerical results confirmed that the guided wave propagation in the fully grouted rockbolt was effective in detecting and quantifying the debonding of rockbolt under pull-out load.

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“…Therefore, in this paper, based on the hammer method used in the non-destructive detecting technology and the wavelet transform analysis, the rock bolt free length, the grouted length, the defect length, and their positions were experimentally studied. Conventional hollow grouted rock bolt has a diameter of 25-32 mm, and the length is ranged from 2 to 10 m. Therefore, for simplification, the anchoring body composed of the rebar and the grout can be regarded as a 1D rod [25,26]. The horizontal inertial effect can be neglected, and the planar interface assumption was used.…”

Section: Introductionmentioning

confidence: 99%

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

Yang

et al. 2018

J Image Video Proc.

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Hollow grouted rock bolts are widely used in deep soft rock roadways. The density of grout has a significant influence on the anchorage quality. However, there is still a lack of effective methods to detect the grouting quality fast, accurately, and extensively. Based on the wave velocity and the law of stress wave transmission and reflection in the impedance mismatch, non-destructive experiment focused on the defect in the anchorage was conducted. The wavelet transform was used to analyze the test signals. The test results show that the free length of hollow grouted rock bolt could be accurately detected through the analysis of the stress wave signal by using the low-pass filter in the wavelet toolbox. The grouted length, defect length, and specific position of the anchorage section can be accurately detected through the analysis of the stress wave signal by using the high-pass filter in the wavelet toolbox. The research can provide experiment foundation for further study of grouting quality based on the non-destructive methods.

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Non-destructive inspection of ground anchors using guided wave propagation

Cited by 29 publications

References 18 publications

Numerical investigation of the core eccentricity effect on wave propagation in embedded waveguide

Numerical investigation of the core eccentricity effect on wave propagation in embedded waveguide

Experimental and numerical evaluation on debonding of fully grouted rockbolt under pull-out loading

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

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