◆ Classification based on position or alignment
a) Saddle and Base Tunnels. To minimize the length of tunnel the track is led through valley as long as natural slope of the valley does not become steeper than ruling gradient of the route. Such tunnels are called ‘Saddle and Base’ tunnels.
b) Spiral Tunnels. In narrow valleys, the additional
length for minimum permissible radius is obtained by forming a loop into the interior of mountain, such tunnels are called ‘Spiral Tunnels’.
c) Off Spur Tunnels. Tunnels that are made to short-cut minor local obstacles. They are very short in length.
d) Slope Tunnels. To ensure safe operation and
protection to railway and highway routes in steep
mountains, ‘Slope Tunnels’ are used. They are also constructed from economic point of view.
No comments:
Post a Comment