Fracturing of migmatite monitored by acoustic emission and ultrasonic sounding

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Fracturing of migmatite monitored by acoustic emission and ultrasonic sounding

Popis výsledku v původním jazyce

Migmatite from the Skalka region (Czech Republic) was chosen as an experimental rock material. It has a macroscopically visible plane-parallel structure (foliation). The foliation was caused mainly by biotite grain arrangement. Four cylindrical specimens of migmatite with sub-horizontal, sub-vertical and oblique foliation were uniaxially loaded up to failure. A network of 8 broadband sensors was employed for acoustic emission monitoring and ultrasonic sounding. A grid search method with an anisotropic velocity model was used for AE hypocenter localization. The source types of successfully localized events were determined from the average first arrival amplitude. Structural anisotropy of the tested rock material caused the anisotropy of its mechanical properties (peak strength, Young's modulus) as well as a different fracturing in dependence on the angle between the axial stress and the foliation plane. The combination of tension and shear microcracking together with sliding in biotite basal planes was found to control the failure of specimens with sub-horizontal foliation. Shearing and sliding were dominant in the failure of specimens with oblique foliation. With greater dip of foliation, the role of sliding increased at the expense of shearing. Due to the favorably oriented system of microcracks already present, the shearing and splitting was at the same level during fracturing of specimens with sub-vertical foliation before nucleation began.

Název v anglickém jazyce

Fracturing of migmatite monitored by acoustic emission and ultrasonic sounding

Popis výsledku anglicky

Migmatite from the Skalka region (Czech Republic) was chosen as an experimental rock material. It has a macroscopically visible plane-parallel structure (foliation). The foliation was caused mainly by biotite grain arrangement. Four cylindrical specimens of migmatite with sub-horizontal, sub-vertical and oblique foliation were uniaxially loaded up to failure. A network of 8 broadband sensors was employed for acoustic emission monitoring and ultrasonic sounding. A grid search method with an anisotropic velocity model was used for AE hypocenter localization. The source types of successfully localized events were determined from the average first arrival amplitude. Structural anisotropy of the tested rock material caused the anisotropy of its mechanical properties (peak strength, Young's modulus) as well as a different fracturing in dependence on the angle between the axial stress and the foliation plane. The combination of tension and shear microcracking together with sliding in biotite basal planes was found to control the failure of specimens with sub-horizontal foliation. Shearing and sliding were dominant in the failure of specimens with oblique foliation. With greater dip of foliation, the role of sliding increased at the expense of shearing. Due to the favorably oriented system of microcracks already present, the shearing and splitting was at the same level during fracturing of specimens with sub-vertical foliation before nucleation began.

Druh

D - Stať ve sborníku

CEP obor

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OECD FORD obor

20701 - Environmental and geological engineering, geotechnics

Projekt

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Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

50th US Rock Mechanics / Geomechanics Symposium 2016

ISBN

978-151082802-5

ISSN

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e-ISSN

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Počet stran výsledku

8

Strana od-do

803-810

Název nakladatele

American Rock Mechanics Association (ARMA)

Místo vydání

Houston

Místo konání akce

Houston

Datum konání akce

26. 6. 2016

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

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