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Lining of tunnel

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Giri Guru

This document discusses tunnel failures and tunnel linings. It notes that tunnels can fail due to discontinuities in the surrounding rock/soil, stratified rock layers, stress, minerals, water pressure, seismic effects, and permanent soil displacement. Tunnel linings are needed to prevent collapse in loose rock and soft soils. Common tunnel lining materials include in-situ concrete, rock shotcrete, wire mesh, steel bolts, and pneumatically applied mortar and concrete. Modern tunnels often use precast concrete blocks for their lining in an advance construction method.

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BY GIRI PRASAD GURUNATHAN
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.
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.
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
Lining of tunnel
Types In situ Concreting Rock Shotcret Wire Mesh
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.
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
Pneumatically applied mortar and concrete are increasingly being used for the support of underground excavation
Lining of tunnel
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.
Advance Type of lining used Now-a-days. Pre casted concrete block is used here.
Lining of tunnel
Thank you Giri Prasad Gurunathan B.Tech. Civil

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Lining of tunnel

  • 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
  • 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