软岩挤压型大变形隧道锚杆施工特性及工艺优化

Optimization of construction machine and technology of bolt for large squeezing deformation tunnel in soft rock

以渭武高速木寨岭隧道大变形段为工程依托,基于对岩石可钻性与钻机性能间关系的分析,选择5种不同类型的锚杆施工机具,进行现场钻孔试验。研究结果表明:低强度炭质板岩挤压型大变形隧道,旋转式钻机应优选额定钻速较高的液压型钻机,冲击-旋转式钻机应优选冲击频率f较高的钻机;钻孔深度以5 m左右为界,超过此深度,钻孔易出现塌孔、卡钻及钻机钻进效率低下等问题,建议5 m以上长锚杆采用自进式;对于5 m内短锚杆的施工,MYT-125/330液压锚杆钻机施工拱顶部位锚杆的有效钻速(除去钻杆加长耗时)约0.8 m/min,YT28钻机施工边墙部位锚杆的有效钻速(除去钻杆加长耗时)约0.4 m/min,施工效果均较为理想;对于10 m长锚杆,采用“大功率台车式钻机+自进式锚杆”,施工功效可达10 m/30 min。

Based on the large deformation section of Muzhailing Highway Tunnel and the analysis of the relationship between rock drillability and drilling rig performance,five different types of bolt construction tools were selected to conduct field drilling tests.The results show that in large squeezing deformation tunnel of low strength carbonaceous slate,rotary drilling rig should select hydraulic drilling rig with higher rated drilling speed,and impact-rotary drilling rig should select drilling rig with higher impact frequency f;The drilling depth should be about 5 m.Once this depth is exceeded which problems such as hole collapse,sticking and low drilling efficiency can easily occur in drilling.It is suggested that self-propelled anchor rods above 5 m should be adopted.For the construction of short bolts within 5 m,the effective drilling speed of MYT-125/330 hydraulic anchor drill is about 0.8 m/min at the vault top and 0.4 m/min at the side wall of YT28 drill,and the construction effect is ideal;For the 10 m long bolts,the construction work of“high-power trolley drill+self-propelled bolt”is adopted.The effect can reach 10 m/30 min.The research results can provide a reference for the selection of bolt tools in large deformation tunnel.