高海拔大断面巷道施工关键技术探讨与思考——以西藏驱龙铜矿为例

Tentative discussions on key technology for large section roadway construction at high altitudes——taking Qulong copper mine in Tibet as a study case

皮带运输巷道的稳定性对于保障矿石运输安全具有重要意义。以西藏驱龙铜矿为例,探明了矿区地层分布,提出了一种基于数字图像处理的RQD智能分级方法,该法可以快速获取皮带运输巷道围岩质量指标(DRQ)值,测试发现钻孔深度超过100 m后,DRQ值基本稳定在74%~80%;利用数值模拟手段对分步施工掘进过程中的上覆围岩变形特性进行了研究,发现巷道穿越破碎带时的围岩位移、应力和塑性变形明显增大;为达到快速安全穿越破碎带的目的,发明了一种岩-泥共存型巷道快速成孔装置,可解决钻孔塌孔、卡钻、施工效率低和成本高等问题。综合考虑运输巷道的长期稳定性和作业成本,建议采用“超前长管棚+锚-索-网+注浆堵水+钢架-衬砌联合支护”方式,支护参数为锚索长度10 m、锚索排间距1.5 m、衬砌厚度200 mm,现场应用效果良好。最后提出了构建不同区段钻孔数据库、结合气象局监测数据将高海拔环境表征定量化、开发高海拔矿产资源的同时须重视高原生态环境修复工作等建议。研究成果可为高寒地区矿产资源的安全高效开发提供借鉴。

The stability of belt conveyance roadway is of great significance to ensure the safety of ore transportation. Taking Qulong copper mine in Tibet as a study case, the strata distribution in the mine was verified. The rock quality designation(RQD) intelligent classification method based on digital image processing was presented by which the rock quality designation(DRQ) of the surrounding rocks in the belt conveyor roadway can be obtained rapidly. It was found that the DRQbasically maintained at 74%~80% once the bore of over 100 m in depth was drilled. The deformation characteristics of the overlying surrounding rock in the process of drifting in steps were studied by means of numerical simulation, it shows that the displacement, stress and plastic deformation of the surrounding rock increased obviously where the tunneling was crossing the fracture zone. In order to achieve the purpose of fast and safe crossing the fracture zone, a rapid holing device for rock-mud roadway was invented, which can solve the problems of hole collapse, stuck drilling, low construction efficiency and high cost. Considering the long-term stability and operation cost of ore transportation in roadway, a supporting mode called "advanced long pipe shed+anchor-cable-mesh+grouting for water plugging+steel frame-lining combination" was proposed. The supporting parameters included the anchor cable length of 10 m, the anchor cable spacing of 1.5 m, and the lining thickness of 200 mm. The field application of the supporting mode resulted in satisfactory performance. Finally, some suggestions were put forward on the construction of drilling database in different sections, on the quantification of high-altitude environment based on the monitoring data from meteorological authority, on requiring more attention to be paid to the restoration of plateau ecological environment during the development of high-altitude mineral resources. The research results can provide reference for the safe and efficient development of mineral resources in the alpine regions.