Experience with electronic initiation in civil tunneling without vibration constraints
In the last decade electronic initiation in drill & blast tunnels has become an accepted technology for improved control of environmental impacts in urban tunneling. The precise delay timing – when compared to traditional pyrotechnic initiation – and the concept of single hole firing have proven to reliably control vibration emissions when firing large rounds without the need to segment the cross-section. However, so far there is limited experience in using electronic initiation in tunnels, which have no environmental constraints. This paper describes experience made with electronic initiation in a Norwegian rail tunnel. The focus of the evaluation of these electronic trials was a comparison of advance rate, perimeter conditions (visible half barrels in the contour), rock support requirements, digging and mucking productivity and overall cycle times when compared to conventional non-electric initiation.