Numerical Simulation of Coal and Gas Outburst using Continuum-based Discrete Element Method

摘要

Coal and gas outburst is a typical hazard that seriously threatens the safety of the miners and the economic efficiency of production in underground coal mines. The mechanisms of coal and gas outbursts are still unresolved but include the effect of stress, gas content and properties of the coal. This paper aims at finding the influences of these parameters especially desorption of methane on outburst behavior and failure process through numerical simulation using Continuum-based Discrete Element Method (CDEM). Simplified model established through MSC Patran is applied to simulate the whole process of coal and gas outbursts, including fracturing of coal bed, gas pressure-driven desorption and expansion, and outburst. The instantaneous outburst process and associated stress fields and displacement vectors are presented step by step. The results of numerical simulations indicate that coal and gas outburst is a complex phenomenon involving interactions between gas pressure, stress and the physic-mechanical properties of the coal, and it can occur under a variety of conditions. Successful numerical simulation of the whole coal and gas outburst process provides the basis for identifying the outburst mechanisms,parameterizing the causative processes, and defining potential precursors of failure.