New Austrian Tunneling Method

New Austrian Tunneling Method ( NATM ) is also known as Sequential Excavation Method or Sprayed Concrete Lining Method. It is generally used in excavation of tunnel in extreme critical situation. This method is recently used in World's Longest Highway Tunnel that is Atal Rohatang Tunnel situated in India.

    

Key Highlights:

• To increase the strength of ground around the tunnel.
• To club off the strength of ground.
• It is suitable in every geological condition
• It is a modern technique.
• It is most cost effective and flexible method
• It is used in region where geological conditions are vary.
• This method is used instead of TBM ( Tunnel Boring Machine )

  

Procedure:

• First of all the blasting is done.
• After the blasting the thin layer of shotcrete.

                                             

• Shotcrete provide protection against loosing of material and rock eformation
• After providing shotcrete the permanent support is laid.