Acoustic emission and ultrasonic velocity study of excavation-induced microcrack damage at the underground research laboratory

Carlson, S R; Young, R. P.

doi:10.1016/0148-9062(93)90042-c

Cited by 48 publications

(37 citation statements)

References 4 publications

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“…Collins and Young [10] reported a mean velocity around the Mine-By tunnel of 5820 m/s for a frequency range of 50-10,000 Hz for the undamaged rock mass. Carlson and Young [5] reported ultrasonic P wave velocities which increased from 5200 to 5900 m/s within 1 m of the sidewall of the Mine-By tunnel. Therefore, the P wave velocity for undisturbed, intact Lac du Bonnet granite is inferred to be close to 6000 m/s at this level of the URL.…”

Section: Discussionmentioning

confidence: 97%

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Assessing in situ microcrack damage using ultrasonic velocity tomography

Meglis

Chow

Martin

et al. 2005

International Journal of Rock Mechanics and Mining Sciences

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Section: Discussionmentioning

confidence: 97%

“…This procedure was chosen over drill-and-blast in order to minimize the damage to the rock mass from the excavation process [3]. This tunnel was extensively instrumented with seismic monitoring arrays in order to detect the microseismic activity associated with tunnel excavation [4,5].…”

Section: Site Descriptionmentioning

confidence: 99%

Assessing in situ microcrack damage using ultrasonic velocity tomography

Meglis

Chow

Martin

et al. 2005

International Journal of Rock Mechanics and Mining Sciences

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“…Geophysical methods have already been demonstrated as useful tools for noninvasive EDZ/HDZ detection. A large amount of research has been conducted on the use of active and passive seismic methods for this purpose (see Carlson and Young, 1993;Cabrera et al, 1999;Backblom and Martin, 1999;Cosma et al, 2001;Alheid et al, 2002;Malmgren et al, 2007, for example). Ground Penetrating Radar (GPR) and resistivity methods have shown potential in a few isolated studies, although their use requires further testing and development (Scott et al, 1968;Kruschwitz and Yaramanci, 2004;Suzuki et al, 2004;Gibert et al, 2006;Silvast and Wiljanen, 2008;Kantia et al, 2013;Lesparre et al, 2013).…”

Section: Introductionmentioning

confidence: 98%

Non-invasive detection of fractures, fracture zones, and rock damage in a hard rock excavation — Experience from the Äspö Hard Rock Laboratory in Sweden

Walton

Lato

Anschütz

et al. 2015

Engineering Geology

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“…The recording of AEs using ultrasonic sensors (frequencies > 30 kHz (PETTITT, 1998)) has become a routine tool for the non-invasive monitoring of microcracking both in situ, (e.g., CARLSON and YOUNG, 1993;YOUNG and COLLINS, 2001) and in laboratory deformation experiments (e.g., SCHOLZ, 1968;LOCKNER et al, 1991;THOMPSON et al, 2006). Previous AE studies have provided invaluable insight into the damage accumulation and rupture geometry within the deformed rock sample (e.g., SCHOLZ, 1968;LOCKNER et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

Accurate Location of Synthetic Acoustic Emissions and Location Sensitivity to Relocation Methods, Velocity Perturbations, and Seismic Anisotropy

Jones

Nippress

Rietbrock

et al. 2008

Pure Appl. Geophys.

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Acoustic emission (AE) monitoring is a non-invasive method of monitoring fracturing both in situ, and in experimental rock deformation studies. Until recently, the major impediment for imaging brittle failure within a rock mass is the accuracy at which the hypocenters may be located. However, recent advances in the location of regional scale earthquakes have successfully reduced hypocentral uncertainties by an order of magnitude. The least-squares Geiger, master event relocation, and double difference methods have been considered in a series of synthetic experiments which investigate their ability to resolve AE hypocentral locations. The effect of AE hypocenter location accuracy due to seismic velocity perturbations, uncertainty in the first arrival pick, array geometry and the inversion of a seismically anisotropic structure with an isotropic velocity model were tested. Hypocenters determined using the Geiger procedure for a homogeneous, isotropic sample with a known velocity model gave a RMS error for the hypocenter locations of 2.6 mm; in contrast the double difference method is capable of reducing the location error of these hypocenters by an order of magnitude. We test uncertainties in velocity model of up to ±10% and show that the double difference method can attain the same RMS error as using the standard Geiger procedure with a known velocity model. The double difference method is also capable of precise locations even in a 40% anisotropic velocity structure using an isotropic model for location and attains a RMS mislocation error of 2.6 mm that is comparable to a RMS mislocation error produced with an isotropic known velocity model using the Geiger approach. We test the effect of sensor geometry on location accuracy and find that, even when sensors are missing, the double difference method is capable of a 1.43 mm total RMS mislocation compared to 4.58 mm for the Geiger method. The accuracy of automatic picking algorithms used for AE studies is ±0.5 ls (1 time sample when the sampling rate is 0.2 ls). We investigate how AE locations are effected by the accuracy of first arrival picking by randomly delaying the actual first arrival by up to 5 time samples. We find that even when noise levels are set to 5 time samples the double difference method successfully relocates the synthetic AE.

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Acoustic emission and ultrasonic velocity study of excavation-induced microcrack damage at the underground research laboratory

Cited by 48 publications

References 4 publications

Assessing in situ microcrack damage using ultrasonic velocity tomography

Assessing in situ microcrack damage using ultrasonic velocity tomography

Non-invasive detection of fractures, fracture zones, and rock damage in a hard rock excavation — Experience from the Äspö Hard Rock Laboratory in Sweden

Accurate Location of Synthetic Acoustic Emissions and Location Sensitivity to Relocation Methods, Velocity Perturbations, and Seismic Anisotropy

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