高应力软岩隧道锚杆(索)成孔钻具研究  

Study on drilling tool for anchor bolt(cable)in high stress soft rock tunnel

作　　者：郭新新[1] 王振宇[1] 汪波[1] 程星源 乔小兵 GUO Xinxin;WANG Zhenyu;WANG Bo;CHENG Xingyuan;QIAO Xiaobing(Key Laboratory of Transportation Tunnel Engineering,Ministry of Education,Southwest Jiaotong University,Chengdu 610031,China;Gansu Changda Highway Co.,Ltd.,Lanzhou 730030,China)

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室,四川成都610031 [2]甘肃长达路业有限责任公司,甘肃兰州730030

出　　处：《铁道科学与工程学报》2022年第7期2080-2089,共10页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(U2034205,51878571);甘肃省科技计划资助项目(19ZD2GA005)。

摘　　要：为解决高应力软岩隧道锚孔,尤其是深锚孔的稳定有效成孔难题,以渭武高速木寨岭公路隧道为工程依托,对围岩钻孔机理进行分析,选择适宜锚杆钻机与不同型号和不同参数的钻具,开展现场钻进和锚索安装试验。从钻具失效模式、钻进工效、使用寿命及成孔效果等方面研究高应力软岩隧道适宜成孔钻具。研究结果表明:钻孔直径增加导致钻具螺纹连接处的应力复杂化,钻具出现了连接处断裂的非常规失效模式。后倾角是PDC钻具钻进工效和使用寿命的关键影响因素,设计应以20°为基准,软岩条件下适当减小其值可显著提升钻进功效,但会减小钻具的使用寿命。小、大组合式钻具由导向钻具(28 mm)和扩孔钻具(45 mm)组成,其中的导向钻具起到了增强钻具定位、提前释放围岩高应力作用,且采用较小后倾角(17.5°)设计以实现快速钻进。扩孔钻具采用3 PDC片形式以实现锚孔圆顺性的提升,使得小、大组合式钻具在使用寿命和成孔效果等方面较单一直径钻具均有显著提升,单个使用寿命达到60 m,10 m锚索的机械推入率降至9%。研究成果可为适配高应力软岩隧道(深)锚孔有效钻进需求的成孔钻具选型提供支撑和实践基础。In order to solve the problem of stable and effective hole forming of anchor holes in high stress soft rock tunnel,especially deep anchor holes,the Muzhailing highway tunnel of Weiyuan-Wudu expressway was selected as the engineering support,and the drilling mechanism of surrounding rock was analyzed.The suitable anchor drills and drilling tools with different types and parameters were selected to carry out field drilling and anchor cable installation tests,and suitable drilling tools for high stress soft rock tunnels were studied from the aspects of drilling tool failure mode,drilling efficiency,service life and hole forming effect.The results show that the increase of borehole diameter complicates the stress at the threaded connection,resulting in unconventional failure modes of connection fracture.The caster angle is a key influencing factor of the drilling efficiency and service life of PDC drilling tools.The design of caster angle should be based on 20°.Under soft rock conditions,appropriately reducing its value can significantly improve the drilling efficiency,but it would reduce the service life of the drilling tool.Small and large combined drilling tools are composed of guided drilling bit(28 mm)and reaming drilling bit(45 mm).The guided bit has the functionalities of enhancing positioning and releasing the high stress of the surrounding rock in advance,itwas designed with a small caster angle(17.5°)to achieve rapid drilling,and the reaming bit used 3 PDC blades to improve the roundness of the anchor hole.The combination of guided bit and reaming bit makes the small and large combined drilling tools significantly improve the service life and hole forming effect as compared to single diameter drilling tools.The service life of a single small and large combined drilling tool can reach 60 m,and the mechanical push-in rate of 10 m anchor cable was reduced to 9%.The research results can provide support and practical foundation for the selection of hole-forming drilling tools that meet the requirement of effec

关 键 词：隧道工程 高应力软岩 PDC片 钻孔试验 组合式钻具 

分 类 号：U451[建筑科学—桥梁与隧道工程]