定向钻技术在隧洞超前地质预报中的应用初探

Application of directional drilling technology in geological forecast of tunnels

摘要:

由于地质条件复杂性及当前针对深埋长隧洞勘察设备、相关技术理论的局限性，深埋长隧洞工程在施工前勘察期间很难全面查明相关工程地质问题，可能对工程的顺利实施造成一定影响。探索将定向钻探技术运用于深埋长隧洞施工期超前地质预报工作，利用水平定向钻机较好的导向功能及长距离快速钻进特点，实现对隧洞掘进前方重大风险的超前探测，为超前处理及应急措施提供依据, 有效弥补常规技术手段下长距离超前探测的不足。本文结合引江补汉工程7#施工支洞，根据不同的地质条件及预报重点，采用了不同类型钻机进行了超前预报技术方法探索，并对比分析了超前预报成果及实际开挖揭露地质条件。分析认为定向钻技术旨在超前探测开挖面前方重大致灾构造，结合钻进特征、物探测试等手段可基本实现目的，为提高预报时效性，钻孔宜减少取心的比率。基于现有技术水平分析，定向钻钻进效率高于钻爆法、TBM法开挖掘进效率，可实现超前探测，定向钻技术在钻爆法、TBM法施工隧洞的超前探测方面具备可行性。

Abstract:

Due to the complexity of geological conditions and the limitations of survey equipment and related technical theories for deep buried long tunnels. It is difficult to achieve a clear understanding during the survey period before construction, which may affect the construction of the project to some extent. It is proposed to carry out application of directional drilling technology for the geological prediction during the construction of deep buried long tunnels, utilizing its good guiding function and rapid long distance drilling characteristics, in order to achieve advanced detection of major risks ahead of tunnel excavation and provide a basis for advanced treatment and emergency measures. It can compensate for the shortcomings of long-distance advanced detection. Different types of drilling rigs are used for the geological forecast of 7#tunnel based on different geological conditions and prediction priorities, the advanced forecast results and the geological conditions revealed by excavation are compared and analyzed. The purpose of directional drilling application is to detect major disaster bodies in front of the tunnel excavation face in advance. It is suggested that the drilling can generally be carried out without coring to improve the timeliness of prediction, in view of the goal can be achieved by combining drilling characteristics and geophysical testing. Based on the current technological level, the efficiency of directional drilling is higher than tunnel excavation of blasting method and TBM method. Directional drilling technology is feasible in the advanced detection of tunnels constructed by blasting or TBM method.