采空区自燃指标的时空分布特征及危险域划分

Temporal and Spatial Distribution Characteristics of Spontaneous Combustion Index in Goaf and Division of Risk Zone

为研究煤矿工作面采空区氧浓度分布的规律、判别采空区自燃危险性及自燃危险区域,采用埋设热电偶传感器及采样束管,对采空区埋深增加导致的监测温度变化、气体含量变化进行汇总分析。通过建立数学方程研究工作面采空区煤原生赋存的CH_(4)、C_(2)H_(6)气体之间的关系,得出采用指数函数拟合度最高达0.952 7。利用采样束管得出采空区内不同位置O_(2)浓度的变化规律,并根据实际情况用Fluent建立了物理模型,对模型的边界条件进行了分析设定,得出随埋深增加氧浓度逐渐下降且下降程度逐渐降低。通过对煤矿工作面采空区氧浓度带进行现场试验和实验室数据模拟,得到了采空区中不同位置“三带”(散热带、氧化带、窒息带)的扇形区域,为防灭火工作提供了指导。

In order to study the law of oxygen concentration distribution in the goaf of the coal mine working face, identify the risk of spontaneous combustion in the goaf and the risk area of spontaneous combustion, the buried thermocouple sensor and sampling bundle tube are used to summarize and analyze the monitoring temperature changes and gas content changes caused by the increase of the buried depth of the goaf, and the relationship between the CH_(4)and C_(2)H_(6)gas originally stored in the goaf coal of the working face is studied by establishing a mathematical equation, and it is concluded that the exponential function has the highest fitting degree, 0.952 7. The change rule of O_(2)concentration at different positions in the goaf is obtained by using the sampling bundle tube, and the physical model is established with Fluent according to the actual situation. The boundary conditions of the model are analyzed and set, and it is concluded that the oxygen concentration gradually decreases and the degree of decline gradually decreases with the increase of burial depth. Through the field test and laboratory data simulation of the oxygen concentration zone in the goaf of the coal mine working face, the fan-shaped areas of the “three zones”(heat dissipation zone, oxidation zone and suffocation zone) at different positions in the goaf are obtained, which provides guidance for the fire prevention work.