地应力场中含瓦斯煤岩变形破坏过程中瓦斯渗透特性的试验研究

TEST STUDY OF GAS SEEPAGE CHARACTERISTICS OF GAS-BEARING COAL SPECIMEN DURING PROCESS OF DEFORMATION AND FAILURE IN GEOSTRESS FIELD

利用典型煤与瓦斯突出矿井松藻煤电集团打通一矿突出煤层原煤制备型煤试件,应用自行研制的含瓦斯煤样三轴瓦斯渗流试验装置,进行含瓦斯型煤试件的全应力–应变过程瓦斯渗透特性变化规律的试验研究。研究结果表明:恒定瓦斯压力时,在某一围压下,峰前渗流速度随轴向应力先减小后缓慢增大,到达峰值应力后,随轴向应力的减小而增大。全应力–应变过程曲线与渗流速度–轴向应变曲线具有较好的对应关系。煤样的峰值渗流速度随围压的增加而减小,呈现较明显的线性关系。对比试验表明,在一定的围压和瓦斯压力范围内,保持瓦斯压力不变增加围压可减小煤样渗透率,保持围压不变增加瓦斯压力可增大煤样渗透率。研究结果对于利用地应力场抽采瓦斯、通过瓦斯涌出量预测煤岩的变形破坏具有现实指导意义。

Based on the briquets of the outburst coal seam of typical coal and gas outburst mine of Datong in Songzao Coal and Electricity Company, by means of self-developed triaxial gas-seepage experimental device, the experimental research of permeability of gas-bearing briquets in the complete stress-strain process is performed. The research results show as follows： if the gas pressure is fixed, the seepage velocity of briquets drops at first and rises later with increasing axial stress, and increases after peak stress. There is significant corresponding relationship between the complete stress-strain process curve and the seepage velocity-strain curve. The seepage velocity in peak stress decreases with the increase of confining pressure, and indicates obvious linear relationship. The comparative experiments in certain confining pressure and gas pressure show that rising confining pressure can decrease permeability of briquets and rising gas pressure can increase permeability of briquette specimens. The results have a referential value for using geostress field draining gas in coal bed and predicting deformations and failure of coal through gas emission.