Abstract

From the viewpoint of interaction mechanics of solid and gas, a coupled mathematical model is presented for coal/rock mass deformation and gas leak flow in parallel deformable coal seams. Numerical simulations for the prediction of the safety range of mining of protection layer are performed with experimental data from a mine with potential danger of coal/gas outbursts. Analyses show that the numerical simulation results are consistent with the measured data on the spot. Therefore, the coupled model shows a positive future for applications in a wide range.

ZUSAMMENFASSUNG

Von der Veranschaulichung der Abhangigkeit Mechaniker fuer Körper und Gas, wird ein verbundenes mathematisches Modell fuer festen coal/rock Deformation und Gasleckstelle Fluß in parallele deformable Kohlenahte dargestellt. Numerische Simulationen fuer die Vorhersage der Sicherheit Strecke, die Schutzschichtbergbau verwendet, werden mit experimentellen Daten von einer Grube mit möglicher Gefahr der coal/gas Ausbrueche durchgefuehrt. Analysen zeigen, daß die numerischen Simulation Resultate mit den gemessenen Daten bezueglich des Punktes gleichbleibend sind. Folglich zeigt das verbundene Modell eine positive Zukunft fuer Anwendungen in einer breiten Strecke.

RÉSUMÉ

Du point de vue de la mecanique d'interaction pour le solide et le gaz, un modèle mathematique couple est presente pour l'ecoulement plein de deformation de coal/rock et de fuite de gaz dans les filons houillers deformable parallèles. Des simulations numeriques pour la prevision de la gamme de sûrete employant l'exploitation de couche de protection sont effectuees avec des donnees experimentales d'une mine avec le danger potentiel des accès de coal/gas. Les analyses prouvent que les resultats numeriques de simulation sont conformes aux donnees mesurees sur place. Par consequent, le modèle couple montre un futur positif pour des applications dans un eventail.

Introduction

Underground coal seams are mostly distributed in adjacent multi-layers in most countries of the world, especially in China. Many problems in mining engineering remain unsolved such as prediction and control of methane gas emission from the coalface during mining, distinction of effective protective area to prevent gas outbursts in protective layer mining, prediction of methane gas drainage rate from adjacent mining seam or from original coal seams in multi-coal-seam. These problems, in essence, are linked with rock mass deformation and gas leak flow (Sun, 1998, 1999, 2002).

Under the action of pressure gradient of a pore gas in the multi-coal-seam system, leaking through the layer of intercalary strata with low permeability, the gas of neighbor seams flows into the coal mining stope or gas drainage bores. This forms gas leak flow field of the multi-coal-seam system (Sun 1998). During coal mining and gas drainage, mining and gas drainage cause gas flow in the multi-coal-seam system, lead the effective stress of the solid skeleton of coal/rock mass to change and the pore pressure in the coal seam or gas drainage bores to change too. These changes lead to a gas flow through a network of micro-pores and micro-cracks. Moreover, the variance of factors of the gas permeability causes the gas flowing change through coal/rock cracks (Sun, 1990; Zhao, 1994).

This content is only available via PDF.
You can access this article if you purchase or spend a download.