深孔松动爆破切顶在保护层开采中的技术实践

中国平煤神马集团平煤股份十二矿,河南 平顶山 467000

松动爆破; 透气性; 预抽率

Practice of deep hole loose blasting technology in the protective layer mining
DAI Jian-bing

(Twelve Coal Mine of Pingmei Shares China Pingmei Shenma Group,Pingdingshan,467000,China)

loose blasting; gas permeability; drainage rate

备注

深孔松动爆破可以增加煤层透气性系数、缓慢排放煤体瓦斯、降低瓦斯压力和瓦斯含量,从而降低了煤体瓦斯压缩内能,提高了煤体的机械强度,达到减弱或消除煤与瓦斯突出危险的目的 。同时有利于使煤体原集中应力带及高压瓦斯带移向煤体深部,即增加卸压带的宽度,减少瓦斯抽放时间,从而提高工作面回采速度。对于松动控制卸压爆破,在爆破孔周围布置了不装炸药的控制孔,控制孔在爆破过程中起到控制爆破方向与补偿爆破裂缝空间作用。由于控制孔的控制导向作用,结果是在介质内部的炮孔周围产生一柱状的压缩粉碎圈和一沿爆破孔与控制孔连心线方向的贯穿爆破裂缝面。控制孔的存在相当于在爆破孔周围增加了辅助自由面,相对缩小了爆破抵抗线的长度,使爆破更有利于形成更大范围的破碎圈带和松动圈带。松动控制卸压爆破可以极大地破坏了煤岩体的整体性,可以消除回采过程中大跨度悬顶悬露以及回转下沉对沿空留巷围岩的影响,同时提高被保护层煤层的透气性,提高抽采钻孔的预抽率,有效地释放地应力,消除煤与瓦斯突出危险性。十二矿作为埋深达千米的矿井之一,在己15-31010工作面采取了该防突措施后,大大提高了抽采钻孔的预抽率,使瓦斯应力和地应力得以提前释放,有效地防治煤与瓦斯突出和冲击地压,并成功优化了留巷区域应力场,确保了保护层开采的正常安全进行。

The deep blasting hole can increase the permeability coefficient of coal gas,decrease slowly gas pressure and gas content,thereby reducing gas compression energy,improving the mechanical strength of coal body,reducing or eliminating the hazard of coal and gas outburst.At the same time contribute to the coal body original stress concentration zone and high pressure gas zone is shifted to deep coal,which increases the pressure relief zone width,reducing gas drainage time,so as to improve the speed of working face mining.But for the loose controlled blasting pressure relief,control hole dynamite blasting hole was not arranged in the surrounding,control hole in the blasting process controlled the blasting direction and compensation effect of blasting cracks space.Because the control oriented role to control the hole,the hole around the inside of the media have a columnar compression through blasting crack surface grinding ring and a along the blasting hole and control hole center line direction.Control hole exists is equivalent to the increase in the auxiliary free surface around the blast hole blasting resistance,relatively narrow line length,the blasting fragmentation circle is more favorable to form a wider band and loose belt.After blasting hole formed near the fracture zone and fractured zone,greatly undermined the integrity of coal and rock mass,can eliminate the large span roof hanging in the process of extraction and rotation sinking on the influence of gob,while improving the permeability of protected seam,improve drainage borehole pre pumping rate,effectively release stress,eliminate the danger of coal and gas outburst.As one of Twelve mine mine depth of KM,Ji15-31010 working face was took the outburst prevention measures,greatly improving the rate of the drainage borehole pre pumping,the gas stress and the stress was released,effectively control coal and gas outburst,and optimized the left lane area stress field,ensured the normal safety protection layer mining.