穿越富水煤层段井巷防治水技术研究

Research on water prevention and control technology for mine roadway engineering crossing water-rich coal seam

为解决陕北侏罗纪煤田内个别矿井受到的严重煤层水害问题,以榆横北区巴拉素井田为例,对其井巷工程穿越富水煤层段防治水技术进行研究。巴拉素井田2号煤层裂隙发育、沟通联系密切,局部存在高压强富水地段,通过井上下联合的钻探、注浆工程对其巷道通过富水煤层段进行水害超前防治。具体主要采用钻孔探查、帷幕注浆、水化学测试、理论分析、孔中窥视、揭露验证等方法,探究了该类水害条件下的矿井防治水技术。结果表明:井下局部煤层水压可达3.81 MPa,单孔最大涌水量198 m^(3)/h;通过钻孔高压注浆形成局部阻水帷幕,单孔起压至约10 MPa可完成煤层水封堵;治理后的钻孔出水pH值在12.20~12.58,平均约12.32,呈强碱性,水质类型大多为OH·SO_(4)-Ca·Na型,证明其注浆材料已充分进入煤层裂隙中;各钻孔之间存在水力联系,结合一次注浆、二次扫孔后的地面注浆压力、钻孔水量水压等数据变化情况,分析判断其封堵效果良好,计算总水量衰减约97.5%以上;通过钻孔窥视进行直接观察,发现注浆治理后的煤岩层段裂隙基本不再出水;根据施工验证钻孔发现注浆改造区域钻孔涌水量不足1 m^(3)/h,巷道实际揭露时的掘进涌水量为1.2 m^(3)/h,最终实现了掘进巷道通过富水煤层段的煤层水害有效防治。本次研究针对陕北侏罗纪煤田榆横北区的煤层水害隐患,提出了“钻孔探查、地面制浆、井下注浆、测试分析、窥视验证”的综合防治水技术,确保了矿井巷道通过2号富水煤层段的安全掘进,为区内条件类似矿井的煤层水害防治工作提供了实际借鉴依据。

To reduce the serious coal seam water hazards faced by some mines in Jurassic coalfield of northern Shaanxi Province,this paper studies the water prevention technology of the roadway engineering crossing water-rich coal seam section,taking Balasu mine field in Yuheng north area as an example.No.2 coal seam in Balasu mine field,whose fractures are well developed and closely connected,contains some high pressure and strong water-rich sections.Measures such as joint drilling and grouting engineering of surface-underground of the mine,can be taken to reduce the water hazards.To verify the mine water prevention technology under such water damage conditions,we adopted the methods of drilling exploration,curtain grouting,water chemical testing,theoretical analysis,peep in the hole,exposure and verification.Results show that the water pressure of local coal seam can be 3.81 MPa,the maximum water inflow from single borehole is about 198 m^(3)/h.We conclude that the coal seam water plugging is completed when the single borehole pressure reaches 10MPa by drilling high-pressure grouting.The strongly alkaline treated borehole water with a pH value range between 12.20 and 12.58(with an average of 12.32),and the water of OH·SO_(4)-Ca·Na type,proves that the grouting material has fully entered the coal seam cracks.The hydraulic connection between each borehole,along with the data changes of ground grouting pressure,water yield and water pressure of borehole after primary grouting and secondary borehole drilling,proves that the plugging effect is good,with a total water attenuation of more than 97.5%.The water is basically no longer out of the coal seam cracks after grouting treatment based on the direct observation from the peep of the borehole.The water inflow of the borehole in the grouting reconstruction area is less than 1 m^(3)/h,and the water inflow of the roadway tunnelling is 1.2 m^(3)/h when the roadway is actually exposed according to the construction verification.Thus,the coal seam water hazards in the tunnelling roadway through the water-rich coal seam section is effectively reduced.Based on the study of the coal seam water hazards reduction in Yuheng north area of Shaanxi Jurassic coal field,this paper puts forward the comprehensive water prevention and control technology of exploration drilling and ground pulping,borehole grouting,test and analysis,peer validation,which ensures the safe tunneling of the mine roadway through the No.2 water-rich coal seam section,and provides a practical reference for the prevention and control of coal seam water damage in similar mines in the area as well.