Drainage, Lighting and Ventilation in Tunnels - IES Previous Year Questions

1. Which one of the following methods is generally considered the best for tunnel ventilation ?

[IES 2007]

  1. ‘Blow in’ method
  2. ‘Blow out’ method
  3. Combination of ‘Blow in’ and ‘Blow out’ methods
  4. Driving a drift through the tunnel
Answer: Option C
Explanation:
  • In the ‘blow in’ method, fresh air is blown uniformly at the workplace. But, foul air, smoke and dust slowly move out fogging the atmosphere inside the tunnel.
  • In the ‘blow out’ method, foul air, smoke and dust are sucked out from the workplace. But, the fresh air has to travel long distance to reach the workplace. During this transit, fresh air may absorb heat and foul gases of the hauling equipment and may result in unpleasant working conditions.
  • Hence, a combination of both ‘blow in’ and ‘blow out’ methods is best for ventilation in tunnels.

2.  How can additional access, quick removal of muck and natural ventilation in long tunnels be achieved ?

[IES 2008]

  1. By providing scaffolding and liner plates
  2. By providing adits and shafts
  3. By providing pilot tunnels and well points
  4. By providing jumbos and pumps
Answer: Option B
Explanation:
Adits and shafts are provided in tunnels during its construction for the following purposes:
  • Natural ventilation
  • Removal of muck
  • Additional access
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