Deformation-and fracture-induced acoustic emission in rocks

Лавров, А. В.; Шкуратник, В. Л.

doi:10.1134/1.2133948

Cited by 31 publications

(19 citation statements)

References 36 publications

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“…The micro-cracks generate a large number of weak acoustic emissions, which leads to a relatively high b value, while macro-cracking leads to relatively low b values since they generate a large number of strong AE signals. Hence, a sharply decreasing b value can often be used as an indicator of near-peak stress [17], [18], [19].…”

Section: State Of the Art 31 B Valuementioning

confidence: 99%

Experimental Study on Acoustic Emission Characteristics of Phyllite Specimens under Uniaxial Compression

Zhao¹,

Zhi-Cheng²,

Zhou³

et al. 2015

JESTR

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In order to obtain acoustic emission (AE) characteristics of phyllite specimens, AE tests of phyllite specimens under uniaxial compression were carried out. Results indicate that there are three distinct failure modes. The main mode is an extension mode. The others are a shear mode and a coupling of the shear and extension modes. A relative quiescence period of AE may appear before the peak stress for any failure mode. The ratio of the cumulative hits and the cumulative energy (named the r value and the Ib value respectively) are used for AE test results analysis. The plots of the Ib value show that the value variation is complex and usually decreases before the peak stress. Before the peak stress the r value decreases continuously and then keeps a relatively slow variation. After the peak stress the r value increases dramatically. The r value appears to be in a U-shape distribution. The Ib value usually decreases while the r value keeps a relatively low variation during the pre-peak stress stage, and the r value increases sharply after the peak stress. This can be used as a basis for determining the pre-or post-peak stress state.

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Section: State Of the Art 31 B Valuementioning

confidence: 99%

Experimental Study on Acoustic Emission Characteristics of Phyllite Specimens under Uniaxial Compression

Zhao¹,

Zhi-Cheng²,

Zhou³

et al. 2015

JESTR

View full text Add to dashboard Cite

show abstract

“…Acoustic emissions are high‐frequency, short‐lived, elastic waves generated by the rapid release of stored elastic strain energy from a localized source [ Lockner , 1993]. In brittle materials, dislocations, grain boundary movements, twinning, and growth of microfractures through or between grains cause acoustic emissions [e.g., Lavrov and Shkuratnik , 2005]. Detection of AE signals is done with piezoelectric transducers that convert mechanical vibration into an electrical signal.…”

Section: Acoustic Emissionsmentioning

confidence: 99%

Fiber bundle model for multiscale modeling of hydromechanical triggering of shallow landslides

Cohen

Lehmann

2009

Water Resources Research

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[1] Sudden and rapid mass movements associated with landslides and snow avalanches present a hazard to life and infrastructure, yet their predictions and triggering mechanisms remain poorly understood. Statistical methods and correlative studies have been used to produce landslide or avalanche susceptibility maps, often with limited physical basis. Mechanistic approaches based on factor-of-safety computation seldom represent the progressive transition from local failure events to a landslide and, in general, do not include heterogeneities associated with land cover or with subsurface material properties and hydrologic pathways. Focusing on rainfall-induced shallow landslides, we propose the use of the fiber bundle model (FBM), a generic yet powerful and adaptable model used in modeling fatigue and fracture of complex and disordered materials. The primary strength of the FBM is its ability to represent the progressive failure of cracks and shear zones and the ruptures of highly heterogeneous bonding elements that are present in soils at all scales. The model also provides a natural framework for interpretation of acoustic emission signatures from failing slopes, which may form the basis of a monitoring and warning system.

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“…Acoustic emissions are high‐frequency, short‐lived, elastic waves generated by rapid release of stored elastic strain energy from a localized source [ Lockner , 1993]. In crystalline rocks, dislocations, grain boundary movements, twinning, and growth of fractures through or between mineral grains cause acoustic emissions [e.g., Lavrov and Shkuratnik , 2005]. The AE waveform is transformed through wave propagation, sensor response, and signal acquisition, so the observed signal bears little resemblance to the original waveform.…”

Section: Apparatusmentioning

confidence: 99%

Role of transient water pressure in quarrying: A subglacial experiment using acoustic emissions

et al. 2006

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[1] Probably the most important mechanism of glacial erosion is quarrying: the growth and coalescence of cracks in subglacial bedrock and dislodgement of resultant rock fragments. Although evidence indicates that erosion rates depend on sliding speed, rates of crack growth in bedrock may be enhanced by changing stresses on the bed caused by fluctuating basal water pressure in zones of ice-bed separation. To study quarrying in real time, a granite step, 12 cm high with a crack in its stoss surface, was installed at the bed of Engabreen, Norway. Acoustic emission sensors monitored crack growth events in the step as ice slid over it. Vertical stresses, water pressure, and cavity height in the lee of the step were also measured. Water was pumped to the lee of the step several times over 8 days. Pumping initially caused opening of a leeward cavity, which then closed after pumping was stopped and water pressure decreased. During cavity closure, acoustic emissions emanating mostly from the vicinity of the base of the crack in the step increased dramatically. With repeated pump tests this crack grew with time until the step's lee surface was quarried. Our experiments indicate that fluctuating water pressure caused stress thresholds required for crack growth to be exceeded. Natural basal water pressure fluctuations should also concentrate stresses on rock steps, increasing rates of crack growth. Stress changes on the bed due to water pressure fluctuations will increase in magnitude and duration with cavity size, which may help explain the effect of sliding speed on erosion rates.

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Deformation-and fracture-induced acoustic emission in rocks

Cited by 31 publications

References 36 publications

Experimental Study on Acoustic Emission Characteristics of Phyllite Specimens under Uniaxial Compression

Experimental Study on Acoustic Emission Characteristics of Phyllite Specimens under Uniaxial Compression

Fiber bundle model for multiscale modeling of hydromechanical triggering of shallow landslides

Role of transient water pressure in quarrying: A subglacial experiment using acoustic emissions

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