高瓦斯特厚煤层首采工作面瓦斯涌出分布特征研究

摘要

In order to the gas emission and distribution characteristics of the first fully-mechanized mining face in high gas and thick coal seam , the 40201 working face of Xiaozhuang Coal Mine was identified as the research ob-ject.By the method of three-dimensional unit measurement , working face gas volume fraction are measured , and the curves of gas distribution and emission in working face along the tendency and trend was obtained .Research shows that , with the increase of wind direction distance in working face , the influence of coal gas emission for gas distribution on cross section is increased , and the influence of wind speed and the goaf gas emission is decreased . Gas volume fraction in trend of each measurement section is mainly present the distribution trend of “high-low-high”.These three factors of coal gas desorption accumulation , the goaf gas emission and wind speed jointly decide the working face gas values in forepart of working face along upward , and mainly from the former two factors in the back end .In the early mining of absolute gas emission quantity rising , for the first time when first weighting was come up to the peak , after presenting wave decline .The relationship present exponential function decreasing trend between relative gas emission quantity and daily output , and it is basically not influenced by the change on the daily output after reaching a certain value .%为了得到高瓦斯特厚煤层首采综放工作面瓦斯涌出分布特征，以小庄煤矿40201工作面为研究对象，采用立体单元测定法对工作面瓦斯体积分数进行测定，得到了工作面沿倾向和走向方向的瓦斯分布曲线以及瓦斯涌出变化曲线。研究表明，工作面沿倾向随着风流方向距离的增加，煤体瓦斯涌出对断面瓦斯分布的影响加大；而风流速度和采空区瓦斯涌出的影响作用在减小。在走向方向，各测定断面瓦斯体积分数基本呈现“高—低—高”的分布趋势，煤体瓦斯解吸累积、采空区瓦斯涌出与风速三者共同决定工作面上行前段瓦斯值大小，后段则主要由前两者起决定因素。回采初期，瓦斯绝对涌出量不断上升，在初次来压首次达到峰值，之后呈现波浪式下降趋势。工作面相对瓦斯涌出量与日产量之间呈现指数函数减小趋势，当日产量达到一定值后，基本不受其变化影响。