开元煤矿顺层钻孔高水膨胀材料封孔试验研究

Experimental Study on Sealing of High Water Swelling Materials in Bedding Drilling of Kaiyuan Coal Mine

针对我国瓦斯抽采钻孔封孔质量差、漏气严重问题,提出了高水膨胀材料封孔方法。对高水膨胀浆液固结体进行了单轴抗压实验,结果表明:随着水灰比的减小,高水膨胀浆液固结体的强度和弹性模量增大,在进行封孔浆液配置时可参考8:1的水灰比。在开元煤矿3908回风巷进行了水泥砂浆、高水膨胀材料及聚氨酯封孔效果对比试验,试验结果表明,高水膨胀材料封孔技术所封钻孔的初始自然瓦斯涌出量平均值为对比钻孔的48.7倍,衰减系数为对比钻孔的20%,闭气压力为对比钻孔的100余倍,瓦斯浓度为对比钻孔的1.5~3倍。高水膨胀材料封孔具有的瓦斯流量大、衰减慢、浓度高的优势,提高了顺层钻孔的密闭性,保证了超前卸压区钻孔的抽采负压,取得了较好的瓦斯抽采效果。

In response to the problems of poor sealing quality and serious gas leakage in gas extraction drilling holes in China,a high water expansion material sealing method has been proposed.Uniaxial compression test was carried out on the consolidated body of high water expansion grout.The results show that the strength and elastic modulus of the consolidated body of high water expansion grout increase with the decrease of water–cement ratio.When the sealing grout is configured,the water cement ratio of 8:1 can be referred to.The comparative test of sealing effect of cement mortar,high water expansion material and polyurethane was carried out in 3908 return air lane of Kaiyuan Coal Mine.The test results show that the average value of initial natural gas emission of the holes sealed by the high water expansion material sealing technology is 48.7 times of the comparison holes,the attenuation coefficient is 20% of the comparison holes,the gas closing pressure is more than 100 times of the comparison holes,and the gas concentration is 1.5~3 times of the comparison holes.The sealing of high water expansion materials has the advantages of high gas flow rate,slow attenuation,and high concentration,which improves the sealing of the drilling along the layer,ensures the negative pressure of the drilling in the advance pressure relief zone,and achieves good gas extraction results.