| 摘要 |
<p>The mine working tunnel lining has a circular section and is constructed from assembled arch pieces. The overall effect is to give a helicoidal watertight lining. It employs a cylindrical shield and block positioner used inside the shield which is extended as the tunnel working progresses. The helicoidal lining is made in the direction of the tunnel (X-X). It uses, end to end, rods placed axially and engaging in axial openings in successive arch blocks. Locking is effected by radial rods through some of the arch pieces which are held by injected cement in the ground.</p> |
