Discuss the lining of the tunnel

1. BY
GIRI PRASAD GURUNATHAN

2. Tunnel
 A tunnel is an underground passageway, dug through
the surrounding soil/earth/rock and enclosed except for
entrance and exit, commonly at each end.

3. FAILURE
IN
TUNNEL
 i. Failure due to discontinuity: fault, joint, fold
 ii. due to stratified rocks
 iii. Rock fail by stress: squeezing, in fault zone, weak and
expansive soil in deeper zone.
 iv. Fail by mineral control
 v.Water pressure control: swelling
 vi. Seismic effects
 vii. Other permanent soil land displacement
 viii. Failure in shotcrete
 ix. Failure in rock bolt and dowel system etc.

4. LINING
 Tunnels in loose rock and soft soils are liable to disintegrate and,
therefore, a lining is provided to strengthen their sides and roofs so
as to prevent them from collapsing

6. Types
In situ
Concreting
Rock Shotcret
Wire
Mesh

7. The process of placing concrete in situ was
incompatible with timber supports.
The first uses of concrete were for tunnels in good
rock and it was only with the introduction of steel
supports that concrete became the norm for a
tunnel lining material.
In-situ forms used for lining tunnels are, with few
exceptions, of the travelling type, constructed of
steel.

8. Steel Bolts are frequently set in holes drilled
into the rock to assist in supporting the
entire roof or individual rock slabs that tend
to fall into a tunnel

9. Pneumatically applied mortar and concrete
are increasingly being used for the support
of underground excavation

11. Wire mesh is used to support small pieces of loose
rock or as reinforcement for shotcrete.
Two types of wire mesh
chain link mesh commonly used for fencing and it
consists of a woven fabric of wire, tends to be
flexible and strong.
weld mesh.
commonly used for reinforcing shotcrete and it
consists of a square grid of steel wires, welded at
their intersection points.

12. Advance Type of lining used Now-a-days.
Pre casted concrete block is used here.

14. Thank you
Giri Prasad Gurunathan
B.Tech. Civil