ABSTRACT

The section of appropriate prediction index is of great importance for coal and gas outburst prediction. The quantity of gas emission is a key factor directly relating to the outburst risk of tunneling working face in the coal roadways. Therefore, accurately predicting the quantity of gas emission is necessary and critical to prevent and control outbursts. In this paper, using the sphere diffusion equation of coal particle gas and radial unsteady flow equations of coal seam gas to analysis gas flow of fallen coal and coal wall, and a dynamic prediction model of gas emission is established including key factors, research shows that: (1) in tunneling working face, the change rule of gas emission of the new model, in which mechanical state, physical properties of coal seam, roadway tunneling parameters, and gas adsorption parameters are considered, is the same as that of the conventional index, which indicates the feasibility of the new model; (2) The new model shows that the gas emission is positively correlated with the gas pressure, driving speed and permeability coefficient of coal seam, and negatively correlated with the uniaxial compressive strength of coal mass; (3) By comparing the old prediction model of gas emission, the predicted value of the new model is closer to the measured value, fluctuating within a smaller range, and has a higher accuracy after taking the gas emission of coal particle into account. In addition, the multiple characteristics of the coal body in front of the working face are comprehensively considered. The research results offer practical significance for improving gas prevention and control of tunneling working face.

摘要

合适的预测指标部分对于煤与瓦斯突出预测具有重要意义。瓦斯排放量是直接关系到煤巷掘进工作面突出风险的关键因素。因此，准确预测瓦斯排放量对于预防和控制爆发是必要和关键的。本文利用煤颗粒气球面扩散方程和煤层气径向非定常流动方程对落煤及煤壁瓦斯流动进行分析，建立了包括关键因素在内的瓦斯排放动态预测模型，研究表明： ：（1）在掘进工作面，考虑力学状态、煤层物理性质、巷道掘进参数、瓦斯吸附参数的新模型瓦斯排放变化规律，与常规指标相同，表明新模型的可行性；(2) 新模型表明瓦斯排放量与煤层瓦斯压力、驱动速度和渗透系数呈正相关，与煤体单轴抗压强度呈负相关；(3) 与旧的瓦斯排放预测模型相比，新模型的预测值更接近实测值，波动范围更小，在考虑煤颗粒瓦斯排放后具有更高的精度。此外，综合考虑工作面前煤体的多重特征。研究成果对提高掘进工作面瓦斯防治工作具有现实意义。