为解决传统敞开式TBM在进行超前管棚注浆加固时存在管棚倾角过大、支护范围不足等问题，依托乐西高速大凉山1号隧道工程，提出一种适用于敞开式TBM的前置式超前钻探注浆加固技术。对首台国产再制造TBM的护盾结构、多功能齿圈和管棚钻机等进行针对性改造，开展原位超前钻探及注浆加固试验，验证该技术方案应用于软弱地层超前注浆加固的可行性和有效性。试验结果表明： 1) 数字化管棚钻机能够有效识别各钻孔工序并划分地层岩性； 2)相较于常规直接钻孔方式，在小角度条件下取芯开孔方式的钻孔效率提高50%，成孔效果更好； 3) 相较于传统后置式超前管棚，前置式超前管棚倾角更小（仅4°），注浆加固范围更大。该技术在大凉山1号隧道工程的成功应用，验证了其在软弱破碎围岩条件下应用的可行性和有效性。
Conventional advance pipe roof grouting reinforcement
in open tunnel boring machines (TBMs) often results in excessive pipe roof
inclination and insufficient support coverage. To address these issues, a front-mounted
advance drilling and grouting reinforcement technique suitable for open TBMs
was developed and applied in the Daliangshan No. 1 tunnel on the Lechang-Xichang expressway. To implement this technique, targeted
modifications are made to the shield structure, multifunctional cutterhead, and
pipe roof drilling rig of China′s first remanufactured
open TBM. In situ advance drilling and grouting reinforcement tests are
conducted to verify the technique′s feasibility and
effectiveness in soft ground conditions. The results demonstrate the following:
(1) The digital pipe roof drilling rig effectively identifies various drilling
processes and stratigraphic lithologies. (2) Compared to the conventional
direct drilling method, the core-based initiation
method under small-angle conditions improves drilling
efficiency by 50% and yields better borehole quality. (3) The front-mounted pipe roof exhibits a considerably smaller inclination angle
(only 4°) and a larger grouting reinforcement range
than conventional rear-mounted pipe roofs. The
successful application of this technique in the Daliangshan No. 1 tunnel offers
valuable references for the design and modification of open TBMs and research
on advance drilling and grouting reinforcement techniques in soft, weak, and
fractured surrounding rock conditions.
