易自燃煤层放顶煤开采工作面合理长度分析

以采空区自然发火危险为约束条件,用采空区场流方法(数值模拟)和自燃三带理论,结合实例,研究放顶煤开采工作面合理长度问题.得到工作面长度安全临界值与煤的最短自然发火期成正比关系.通过现场测定风量和采空区气体浓度分布,得到在当前工作面特定采空区流场环境下的自燃氧化带宽度和模型基础参数,数值模拟出不同工作面长度的采空区自燃氧化区宽度的变化关系;回归得到,在理论上,工作面长度与自燃氧化带宽度近似服从二次曲线关系.分析中给出了自燃安全判别量和自燃安全区间.

Analysis of a Reasonable Working Face Length for Coal Seams Susceptible to Spontaneous Combustion When Mining by the Top-Coal Caving Method

A reasonable value for the length of a top-coal-caving face, when working with coal at risk for spontaneous combustion, was determined using the goaf field-flow method. This involved the use of the three-zone theory of spontaneous combustion. It appears that the critical length of the working face is proportional to the shortest time during which spontaneous combustion might occur. By measuring the air quantity and gas concentration in the goaf the width of the spontaneous combustion zone and the basic parameters for the working face, given a particular flow-field, could be obtained. Regression analysis showed that the working face length and spontaneous-oxidation-zone width approximate a quadratic relationship. Safety allowances and safety intervals for spontaneous combustion are given.