Alireza Afradi - Ph.D. Student of Mining Engineering, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran
Siamak Rezazadeh - Assistant Professor and Head of the Department of Mining and Geology, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran

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.

drilling, tension, natm