高压水射流自旋式割缝技术在柿花田煤矿的应用

瓦斯治理的根本措施是抽放,然而应用单一钻孔预抽瓦斯,钻孔直径是决定抽放效果的关键因素.孔径小,其自由面小,瓦斯的排放速度低,等待开采的时间较长,影响了矿井的生产效率,而孔径又不能太大,否则在煤层综合应力下,孔的形成和孔的稳定性会受到破坏,而且孔径大的钻孔钻进速度较慢,效率较低,而且钻孔的有效煤孔段往往只占整个钻孔的一小部分,完全没有必要施工孔径较大的钻孔.介绍了一种新型高压水射流自旋式割缝技术,该技术可以有效解决上述问题.高压水射流自旋式割缝设备主要由高压水泵、水箱、高压胶管、高压密封钻杆、旋转接头、力矩喷头和喷嘴组成,该技术是在瓦斯抽采钻孔完成后,利用钻机将切割钻具输送至孔内,采取后退切割的方式,对钻孔内煤体进行切割,形成若干个垂直于钻孔方向的圆盘状缝隙,使孔内煤体暴露面积增加,同时由于高压注水作用,缝隙周围裂隙增加使煤体的透气性增强,从而有效提高抽采效率.试验发现：该技术的割缝半径为0.6～0.7m,使用该技术切割后,瓦斯涌出量大幅增加,百米瓦斯自排量和瓦斯抽放量分别是非切割钻孔的5.6和4.5倍,且衰减系数有所增加.

Application of high pressure water jet cutting technology in Shihuatian mine

The basic measures of gas control is drainage, and the hole diameter is a key factor that deter mine the drainage effect in the single drainage gas drilling application. When aperture is small, the free surface is small, and the gas emission rate is low, the waiting time is long, then affects efficiency of mine production. But the aperture can＇ t be too big for under the comprehensive stress of coal seam, the forma tion of the hole and hole stability will be damaged, and with large aperture the borehole drilling speed will slower, efficient will lower, also effective coal hole drilling segment accounts for only a small part of the whole drilling, so it＇ s unnecessary drilling large aperture. Here introduced a new type high pressure water jet of spin cutting technology and can effectively solve this problem. This device is mainly com posed of high pressure pumps, tanks, high pressure rubber hose, high pressure sealing pipe, rotary joints, torque of nozzle and nozzle. After completion of the gas extraction drilling, using drill deliver the cutting burr to the hole, adopted backward cutting for drilling, forming a number of disc crack perpendicular to the direction of drilling, make the hole exposure area of coal increased, because the effect of the high pressure water injection, the permeability of coal body was enhanced for the crack fracture increase, thus effectively improved the extraction efficiency. Coal mine application found ： the slotted radius of this tech nology is 0.6 0.7 m, the gas emission increased sharply after using this technology, hundreds of meters of gas discharge and gas drainage volume is 5.6 and 4.5 times over noncutting hole respectively, and the attenuation coefficient is increased.