On the Cautious blasting pattern of Weak zone of NAMSAN NO. twin Tunneling

남산1호터널 쌍굴 굴진공사 정밀발파 작업에 대한 안전도검토

  • Huh, Ginn
  • 허진
  • Published : 1990.12.01

Abstract

The $\varphi{4.5}$ meters pilot tunneling work is almost done to the $\varphi{11.3}$ meters twin tunnel of NAM SAN No1. The south side pit of 400 meters is weak zone of Rock status, so client request us to allow the cautious blasting pattern for drilling on the condition of 0.2 kine vibration allowance limited for the safety of side running tunnel. The pattern of cautious blasting carried out by 6 time divided fiving on the round drilling depth of 1.20 meters(1.10) and also applied control blasting method with line drilling due to the reduction of vibration.

Keywords