Study on Rock Burst Early Warning in the Working Face of Deep Coal Mines Based on the Law of Gas Emission

Zhang, Qinghua; He, Shudong

doi:10.1155/2021/9940505

Cited by 2 publications

(1 citation statement)

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“…The current condition of coal and rock mass is estimated using the data of air/gas ratio control, and microseismic and electromagnetic emission monitoring [6][7][8], which are recorded by mine control equipment (MMS [9], MineARC [10]). The interpretation of these data towards a short-term forecast of dynamic events includes: -semi-empirical models (for example, damage accumulation [11]) and statistical space-time analysis of long time series of informative parameters of geodynamic processes (in particular, seismic energy density in the study area) [12][13][14][15][16][17]; T -identification of signs of a dynamic event the initiation mechanism of which is, as a rule, determined from a geomechanical model [18][19][20][21]. 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.…”

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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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