Stability analysis of tunnel Using the Natm Method Case Study: 4th tunnel of Firoozkooh road

This paper analyzes the stability of the tunnel using natm method. The main objective of the failure is to create an external semi-rigid arc immediately after drilling with materials such as concrete, screw, etc. This will cause tension in the area around the tunnel and prevent deterioration. Shows that score Q = 4/52, and later equivalent = 12.4, and use only 2.9 meters long single Bolt single rock and a flat shutter with a thickness of 7 to 12 cm.

Keywords:

drilling , tension , natm