Water-Isolating Capacity of an Inclined Coal Seam Floor Based on the Theory of Water-Resistant Key Strata

A model of an inclined coal seam floor with linearly increasing water pressure was developed based on theories of ground pressure and key strata. The stability metrics of the water-resistant key strata in the inclined coal seam was deduced using Mohr–Coulomb yield criterion. Five principle factors w...

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Veröffentlicht in:Mine water and the environment 2017-06, Vol.36 (2), p.310-322
Hauptverfasser: Sun, Jian, Miao, Xiexing
Format: Artikel
Sprache:eng
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Zusammenfassung:A model of an inclined coal seam floor with linearly increasing water pressure was developed based on theories of ground pressure and key strata. The stability metrics of the water-resistant key strata in the inclined coal seam was deduced using Mohr–Coulomb yield criterion. Five principle factors were selected: the distance that the workface had advanced, the tilted length of workface, the thickness and pitch of the water- resistant key strata, and the elasticity modulus. A sensitivity analysis was then conducted using an orthogonal design. The thickness of the water-resistant key strata was the most important factor, with a 44.8% ranking, followed by the distance that the workface had advanced at 34.4%. The influence of the elasticity modulus, pitch, and tilted length of the workface, were 9.3, 5.8, and 5.7%, respectively. The maximum water pressure possibly tolerated by the inclined aquiclude were found to rise with the increasing load of the caved overburden, and decrease with the increasing workface initial or periodic weighting distance, workface length, and pitch of the water-resistant key strata. A parabolic relationship exists between the maximum allowable water pressure and thickness of the key aquiclude. Water-resistant key strata located in the lower part of the confining layer offers better protection from floor water inrush. These findings provide an important theoretical basis to determine the potential of water inrush from an inclined coal seam when mining above confined aquifers.
ISSN:1025-9112
1616-1068
DOI:10.1007/s10230-017-0428-6