Use of Tomography in Stress–Strain Analysis of Coal–Rock Mass by Solving Boundary Inverse Problems

Nazarova, Larisa; Захаров, В. Н.; Шкуратник, В. Л.; Nazarov, L. A.; Protasov, M.; Nikolenko, P. V.

doi:10.1016/j.proeng.2017.05.278

Cited by 6 publications

(2 citation statements)

References 10 publications

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“…Połączenie wyników CT i testu geomechanicznego może wspomóc planowanie procesu szczelinowania o dodatkowe parametry, tj. wytrzymałość skały na ściskanie, moduły sprężyste, zmianę wielkości parametrów geometrycznych przestrzeni porowej (Nie et al, 2014;Mathews et al, 2017;Nazarova et al, 2017).…”

Section: Wstępunclassified

Wyniki badań testu wytrzymałościowego próbki węgla w świetle badań tomograficznych

Dohnalik

Badawczy

Krakowska-Madejska

et al. 2021

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The study aimed to check the possibility of using computed tomography to observe fractures in coal samples before and after a triaxial compression test (TRX). The paper presents an innovative use of two specialized laboratory techniques: computed tomography and geomechanical triaxial compression test. Geomechanical tests were performed on a TRX-070, GCTS (USA) measuring triaxial system. A full stress-strain characteristic was recorded. Also, during the triaxial compression tests, the P and S wave velocities were measured and dynamic elastic moduli were determined. The results were compared. The sample was analyzed in two stages: CT measurement performed on raw coal sample (stage 1) and after the TRX test which destroyed the sample structure (stage 2). First, the sample was scanned reflecting the initial pores and microcracks system. The final stage represents the sample after the geomechanical test. A detailed pore structure analysis was performed for each of the stages. As a result of the proposed above-mentioned method, images of the pore structure were obtained after each step. The sample was analyzed for crack propagation and changes in the pore structure. The qualitative and quantitative interpretation was based on the determination of the number of voids, crack diameters, collapse angles, and comparison of the pore structure between the initial state of the sample and after the triaxial test. In the first stage (before the test), the largest object (identified as a microcrack) had a volume of approximately 16 mm3, after the sample was stress-tested (after the sample was destroyed), the largest identified object was about 15 times larger (240 mm3). It appeared that the coal sample was prone to fracturing in defined directions. Comprehensive research has demonstrated the legitimacy of using the proposed methodology to evaluate changes in the sample structure during the triaxial test.

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Section: Wstępunclassified

Wyniki badań testu wytrzymałościowego próbki węgla w świetle badań tomograficznych

Dohnalik

Badawczy

Krakowska-Madejska

et al. 2021

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“…Seismic tomography [22][23][24] is recently often used in assessment of rock mass condition; in this case, areas of increased elastic wave velocities are associated with the stress concentration zones which are potential sources of dynamic events. A method for quantifying the external field stresses based on passive tomography data was proposed [25]. The passive methods are disadvantageous in monitoring induced seismicity parameters as they are deficient even for a medium-term forecast to be made or for detecting areas of concern located outside the illuminated domain in the object under study.…”

Section: Introductionmentioning

confidence: 99%

Method for weak zones location at the coal-bed – host rock joint relative to the problem of sudden outbursts: theory and laboratory experiment

Nazarov

2022

Frattura Ed Integrità Strutturale

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Within the framework of a geomechanical model that describes the deformation of a rock mass during the subhorizontal coal-bed extraction, the mechanism for the formation and implementation of a sudden outburst is substantiated: as working face gets close to the weak zone of coal-bed – host rock joint, areas of tensile stresses arise, which creates the prerequisites for face space spalling and coal loss with methane. The inverse problem of determining the conditions at the horizontal boundaries of a coal-bed is formulated and solved using tomography data (longitudinal wave velocity V distribution) and the empirical dependence of V on the mean normal stress σ. Lab tests results on stepwise compression of parallelepipeds made of artificial geomaterials are presented. Tomography of the specimens was performed by acoustic sounding data, and the distribution of velocities V* was found. Using the pre-established empirical dependence V(σ) for geomaterial, the distribution σ*=V-1(V*) in the specimen was calculated, which served as input data for inverse problem of determining the shear stresses σxy at the “specimen faces – press platens” joints. Lab data inversion confirmed the possibility of identifying weak zones of the boundaries where σxy=0. These zones are associated with probable nucleus of failure and sudden outbursts.

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Dynamic Mechanical Properties and Fragment Fractal Characteristics of Fractured Coal–Rock-Like Combined Bodies in Split Hopkinson Pressure Bar Tests

Chen

et al. 2020

Nat Resour Res

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Use of Tomography in Stress–Strain Analysis of Coal–Rock Mass by Solving Boundary Inverse Problems

Cited by 6 publications

References 10 publications

Wyniki badań testu wytrzymałościowego próbki węgla w świetle badań tomograficznych

Wyniki badań testu wytrzymałościowego próbki węgla w świetle badań tomograficznych

Method for weak zones location at the coal-bed – host rock joint relative to the problem of sudden outbursts: theory and laboratory experiment

Dynamic Mechanical Properties and Fragment Fractal Characteristics of Fractured Coal–Rock-Like Combined Bodies in Split Hopkinson Pressure Bar Tests

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