砂质黄土隧道支护侵限段迈式管棚超前支护技术有效性分析

风积砂质黄土构造上具有松散、钻孔成孔困难等特点,这种土质中隧道施工易于发生崩塌.针对朔州隧道进口段拱顶出现塌陷、下沉,喷射混凝土剥落、开裂、下塌变形且侵限等现象,选择采用迈式管棚超前支护技术对初支进行拆换.采用有限元差分软件FLAC3D对风积砂质黄土隧道坍塌体工作面迈式管棚超前支护技术进行了研究,结果表明：迈式管棚超前支护结合迈式径向锚杆可以有效控制支护及围岩变形,实现了侵限段初支安全拆换.该技术措施对同类工程具有一定的参考和借鉴意义.

Efficiency Analysis of Self-drilling Pipe Roof Advanced Support Technology in Beyond Limit Section of Sandy Loess Tunnel

Aeolian sandy loess has the characteristics of loose structure and difficulty in drilling, it is also likely to collapse during construction. The self-drilling pipe roof advanced support technology has been used in view of the construction disaster like vault collapse, subsidence, stripping, cracking, deformation and support beyond limit. The self-drilling pipe roof ad- vanced support technology has been studied by finite elements software FLAC3D. The results show the self-drilling pipe sup- port combined with self-drilling anchor bolt can effective control the deformation of rock mass and support and successfully complete the support replacement. The technique can be adopted in the design, construction and research of similar tunnels.