隧洞勘察大角度同步定向取心钻孔施工技术

Construction technologies of high-angle synchronous directional coring drilling for tunnel investigation

摘要:

为解决高山峡谷地区跨河隧洞勘察难度大、大角度精准定向与绳索取心不同步以及坚硬地层钻进效率低等问题，研发了定向造斜和绳索取心钻进同步技术、大角度定向孔随钻轨迹控制技术、高强度绳索取心钻杆以及铁基预合金分层式取心钻头，结合千米级绳索取心定向钻进装备，探索形成了一套大角度定向取心钻进技术。将研究结果在西部某重大水电工程引水隧洞勘察进行了应用，在河谷左侧布置一个超深L型定向钻孔，取得了如下成果：优质高效完成了1004 m曲线定向取心深钻孔施工任务，平均台月效率197.64 m，全孔平均岩心采取率为94.35%，取心钻进平均机械钻速1.46 m/h；轨迹控制良好，钻孔轨迹顶角由25°增加至78°，满足设计要求；研发的铁基预合金分层式钻头具有明显优势，钻头钻速更快、寿命更长；查明和揭露了河谷底部及两侧的断层和不良地质体，达到地质目标，取得了很好的应用效果。

Abstract:

In order to solve the problems such as the great difficulty of cross-river tunnel investigation in alpine-gorge areas， the asynchronous high-angle precise orientation and wire-line coring， and the low drilling efficiency in hard strata， the synchronous technology of directional deflecting and wire-line coring drilling， the real-time trajectory control technology for high-angle directional holes， high-strength wire-line coring drill rods， and iron-based pre-alloy layered core bits were developed. Combined with the kilometer-level wire-line coring directional drilling equipment， a set of high-angle directional core drilling technology was explored and formed. The research results were applied to the investigation of the diversion tunnel of a major hydropower project in the western region. An ultra-deep L-shaped directional borehole was arranged on the left side of the river valley， and the following achievements were obtained： The construction task of a 1004 m curved directional core drilling deep borehole was completed with high quality and efficiency. The average monthly efficiency of the drilling rig was 197.64 m， the average core recovery rate of the whole hole was 94.35%， and the average mechanical drilling rate of core drilling was 1.46 m/h. The trajectory was well controlled. The top angle of the borehole trajectory increased from 25° to 78°， meeting the design requirements. The developed iron-based pre-alloy layered bit had obvious advantages， with a faster drilling rate and a longer service life. The faults and unfavorable geological bodies at the bottom and on both sides of the river valley were identified and exposed， achieving the geological objectives and obtaining good application results.