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穿层抽放是一些高突矿井常用的瓦斯治理手段,在穿层抽放时采用爆破技术已被证明具有良好的抽放效果。以重庆市南桐矿穿层爆破为背景,建立了穿层深孔爆破数学模型;利用数值计算和现场实测抽放数据相结合的方法,分别研究了各爆破孔、控制孔动应力的变化以及爆破应力场强度与抽放效果的关系。研究结果表明,穿层抽放的特点决定了爆破孔与抽放孔的布孔方式。由于炮孔斜穿煤层,煤层各断面动应力场分布极不均匀,药包中心控制孔所受动应力为控制孔中最大。在南桐矿薄煤层试验条件下,药包长度为3.2 m的爆破孔平均破坏半径为0.57 m,较其他两排炮孔大20%以上。炮孔中药包长度是影响瓦斯抽放量的重要因素。爆破孔的平均单孔抽放量较控制孔高55%,爆破钻场较非爆破钻场平均单孔流量大49%。
Cross-layer drainage is commonly used in some high-gas wells gas control measures, the use of blasting in the process of stratified drainage has been proven to have a good drainage effect. Taking the Nantong mine as an example, the mathematical model of deep borehole blasting through strata was established based on the layer blasting of Nantong mine in Chongqing. By using the combination of numerical calculation and measured data of on-site drainage, the dynamic stress changes of blasthole and control borehole were studied respectively Relationship between blasting stress field strength and drainage effect. The results show that the characteristics of the stratum drainage determine the layout of blasting holes and drainage holes. Because the borehole is diagonally through the coal seam, the distribution of dynamic stress field in each section of the coal seam is very uneven. The stress in the control hole of the medicine bag center is the largest in the control hole. Under the condition of thin coal seam in Nantong Mine, the average failure radius of blasting holes with a length of 3.2 m is 0.57 m, which is 20% more than that of the other two rows of holes. Drum hole length of the Chinese medicine package is an important factor affecting the amount of gas drainage. The average single-hole discharge volume of blasting holes is 55% higher than that of the control holes, and the average single-hole flow rate of blasting drilling sites is 49% larger than that of non-blasting drilling sites.