基于水力压裂增透的多煤层瓦斯隧道快速揭煤防突技术研究  

Research on rapid coal excavation and outburst prevention technology for multi-coal seam gas tunnel based on hydraulic fracturing and permeability enhancement

作　　者：任青阳 柯善剑 刘海军 肖宋强 Ren Qingyang;Ke Shanjian;Liu Haijun;Xiao Songqiang(State Key Laboratory of Mountain Bridge and Tunnel Engineering,Chongqing Jiaotong University,Chongqing 400074,China;China Overseas Construction Co.,Ltd.,Shenzhen 518000,China;China Southwest Geotechnical Investigation & Design Institute Co.,Ltd.,Chongqing 401120,China)

机构地区：[1]重庆交通大学山区桥梁及隧道工程国家重点实验室,重庆400074 [2]中海建筑有限公司,广东深圳518000 [3]中国建筑西南勘察设计研究院有限公司,重庆401120

出　　处：《能源与环保》2022年第1期65-72,共8页CHINA ENERGY AND ENVIRONMENTAL PROTECTION

基　　金：国家自然科学基金(41472262);重庆市高校创新研究群体(CXQT19021);重庆市自然科学基金重点项目(cstc2020jcyj-zdxmX0012)。

摘　　要：为实现瓦斯隧道安全快速有效地揭煤,以正习高速公路天城坝隧道揭煤工程为背景,分析了水力压裂大范围增加煤层透气性原理与增透效果影响因素,基于水力压裂增透技术建立了多煤层瓦斯隧道揭煤防突技术体系,探讨了以超前探测、初探、精探、区域瓦斯防突及检验、工作面防突及检验、验证揭煤等为核心的揭煤防突流程,优化了瓦斯隧道水力压裂防突技术中压裂钻孔布置、压裂工艺、封孔工艺、破裂压力及用水量、抽采钻孔布置等关键工艺参数。C6—C8煤层原始瓦斯压力(1.62~4.12 MPa)、瓦斯放散初速度(18.2~34.0)、煤体坚固性系数(普遍小于0.5)和破坏类型(Ⅲ类)等指标综合表明C6—C8煤层具有突出危险性。对C6煤层进行水力压裂增透后,煤层平均单孔瓦斯抽采纯量0.009 m^(3)/min,抽采浓度在60%以上,抽采30 d后煤层残余瓦斯含量和瓦斯压力分别降为2.91~5.29 m^(3)/t和0.26~0.61 MPa,缩短揭煤时间2个月。研究结果表明,水力压裂技术能有效改善瓦斯隧道揭煤防突效果,为安全快速揭煤工作提供安全保障,对类似隧道揭煤施工具有借鉴意义。In order to realize the safe,fast and effective coal excavation of gas tunnels,taking the coal excavation project of Tianchengba Tunnel of Zhengxi Expressway as the background,the principle of hydraulic fracturing to increase the permeability of coal seams in a large range and the influencing factors of permeability enhancement effect were analyzed.The technology had established a multi-coal seam gas tunnel excavation coal outburst prevention technology system,and discussed the coal excavation prevention and prevention with the core of advanced detection,preliminary exploration,fine exploration,regional gas outburst prevention and inspection,working face outburst prevention and inspection,and verification of coal excavation.The process optimized the key process parameters such as fracturing drill hole layout,fracturing process,hole sealing process,fracture pressure and water consumption,and drainage drill hole layout in the gas tunnel hydraulic fracturing outburst prevention technology.C6-C8 coal seam original gas pressure(1.62~4.12 MPa),initial gas release velocity(18.2~34.0),coal firmness coefficient(generally less than 0.5)and failure type(classⅢ)and other indicators comprehensively showed that the C6-C8 coal seam had outstanding danger.After hydraulic fracturing and permeability enhancement of the C6 coal seam,the average single-hole gas extraction pure volume in the coal seam was 0.009 m^(3)/min,the extraction concentration was above 60%,and the residual gas content and pressure in the coal seam decreased respectively after 30 days of extraction.It was 2.91~5.29 m^(3)/t and 0.26~0.61 MPa,which shortened the coal unloading time by 2 months.The research results showed that the hydraulic fracturing technology could effectively improve the anti-outburst effect of coal excavation in gas tunnels,and provided a safety guarantee for safe and rapid coal excavation work,which had reference significance for similar tunnel coal excavation construction.

关 键 词：瓦斯隧道 煤层群 水力压裂 瓦斯抽采 防突 超前地质预报 

分 类 号：TD712.6[矿业工程—矿井通风与安全]