Method for locating weak zones at coal-bed�host rock interface in the context of outburst hazard: Theory and laboratory experiment

Within the framework of a geomechanical model that describes deformation of rock mass during extraction of subhorizontal coal beds, the outburst hazard mechanism is substantiated: the approach of a working face to a weak zone at the coal-bed�host rock interface initiates tensile stress areas, which...

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Main Authors: Larisa Nazarova, Leonid Nazarov
Format: Article
Language:English
Published: Gruppo Italiano Frattura 2023-01-01
Series:Fracture and Structural Integrity
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Online Access:https://www.fracturae.com/index.php/fis/article/view/3665/3721
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author Larisa Nazarova
Leonid Nazarov
author_facet Larisa Nazarova
Leonid Nazarov
author_sort Larisa Nazarova
collection DOAJ
description Within the framework of a geomechanical model that describes deformation of rock mass during extraction of subhorizontal coal beds, the outburst hazard mechanism is substantiated: the approach of a working face to a weak zone at the coal-bed�host rock interface initiates tensile stress areas, which creates the prerequisites for the face spalling and loss of coal with methane. The inverse problem of determining conditions at the horizontal boundaries of a coal bed is formulated and solved using tomography data (patterns of P-wave velocity V) and the empirical dependence of V on the mean normal stress s. Lab-scale test results on stepwise compression of parallelepipeds made of artificial geomaterials are presented. Tomography of the specimens was performed by acoustic sounding data, and the pattern of velocities V* was obtained. Using the pre-found empirical dependence V(s) for geomaterial, the distribution s*=V-1(V*) in the specimen was calculated, which served as the input data for the inverse problem on the shear stresses sxy at the specimen�press plate interface. The inversion of the lab data confirmed the possibility of identifying weak zones at the boundaries where sxy0. These zones are associated with probable sources of failure and outbursts.
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spelling doaj-art-49e4d8c7cba640f192e98bbef8d4c9892024-12-02T08:49:51ZengGruppo Italiano FratturaFracture and Structural Integrity1971-89932023-01-011763132510.3221/IGF-ESIS.63.0210.3221/IGF-ESIS.63.02Method for locating weak zones at coal-bed�host rock interface in the context of outburst hazard: Theory and laboratory experimentLarisa NazarovaLeonid NazarovWithin the framework of a geomechanical model that describes deformation of rock mass during extraction of subhorizontal coal beds, the outburst hazard mechanism is substantiated: the approach of a working face to a weak zone at the coal-bed�host rock interface initiates tensile stress areas, which creates the prerequisites for the face spalling and loss of coal with methane. The inverse problem of determining conditions at the horizontal boundaries of a coal bed is formulated and solved using tomography data (patterns of P-wave velocity V) and the empirical dependence of V on the mean normal stress s. Lab-scale test results on stepwise compression of parallelepipeds made of artificial geomaterials are presented. Tomography of the specimens was performed by acoustic sounding data, and the pattern of velocities V* was obtained. Using the pre-found empirical dependence V(s) for geomaterial, the distribution s*=V-1(V*) in the specimen was calculated, which served as the input data for the inverse problem on the shear stresses sxy at the specimen�press plate interface. The inversion of the lab data confirmed the possibility of identifying weak zones at the boundaries where sxy0. These zones are associated with probable sources of failure and outbursts.https://www.fracturae.com/index.php/fis/article/view/3665/3721coal and rock masslab testtomographygeomaterialinverse problemoutburst
spellingShingle Larisa Nazarova
Leonid Nazarov
Method for locating weak zones at coal-bed�host rock interface in the context of outburst hazard: Theory and laboratory experiment
Fracture and Structural Integrity
coal and rock mass
lab test
tomography
geomaterial
inverse problem
outburst
title Method for locating weak zones at coal-bed�host rock interface in the context of outburst hazard: Theory and laboratory experiment
title_full Method for locating weak zones at coal-bed�host rock interface in the context of outburst hazard: Theory and laboratory experiment
title_fullStr Method for locating weak zones at coal-bed�host rock interface in the context of outburst hazard: Theory and laboratory experiment
title_full_unstemmed Method for locating weak zones at coal-bed�host rock interface in the context of outburst hazard: Theory and laboratory experiment
title_short Method for locating weak zones at coal-bed�host rock interface in the context of outburst hazard: Theory and laboratory experiment
title_sort method for locating weak zones at coal bed�host rock interface in the context of outburst hazard theory and laboratory experiment
topic coal and rock mass
lab test
tomography
geomaterial
inverse problem
outburst
url https://www.fracturae.com/index.php/fis/article/view/3665/3721
work_keys_str_mv AT larisanazarova methodforlocatingweakzonesatcoalbedhostrockinterfaceinthecontextofoutbursthazardtheoryandlaboratoryexperiment
AT leonidnazarov methodforlocatingweakzonesatcoalbedhostrockinterfaceinthecontextofoutbursthazardtheoryandlaboratoryexperiment