Air Quality During Excavation Of Tunnels In The Rijeka Motorway Bypass

The main sources of dangerous and harmful gases during the excavation of tunnels are blasting operations and application of diesel equipment for loading and transport of excavated rock. Full-face driving of parallel pipes of three tunnels was conducted in the Rijeka Motorway Bypass by blasting operations and the use of diesel equipment. The quality and quantity of air was monitored in accordance with the technical conditions in the workspace of the tunnels. The concentration of harmful and hazardous gases, along with oxygen, was monitored by active continuous measuring with portable instruments. Measurements were conducted at the head of the tunnel, during blasting operations and during the process of loading and transport of the blasted rock mass. A comparative analysis of actual air loss and losses calculated in accordance with the empirical equations was conducted along the ventilation air duct, as well as the air supply requirements.