Comparison of excavation damage zones resulting from blasting with nonel detonators and blasting with electronic detonators

Abstract

The article presents comparison of excavation damage zones resulting from blasting with nonel detonators and blasting with electronic detonators. The nonel detonator is a common type of detonator used in drill-and-blast tunnel excavations, while the use of electronic detonators in recent years has also been gaining popularity in complex tunneling conditions. The tunnel has an overburden of 25 to 40 m. The field study involves an ultrasonic wave measurement in drill holes at two different tunnel sections separately excavated by using electronic detonators and nonel detonators. The results demonstrate that using electronic detonators can help limit the EDZ development in drill-and-blast tunnel excavations. The disturbed zone is dominated by a change of stress and hydraulic head state. The changes in rock mass properties are insignificant or reversible. The presence of the failed zone and damaged zone affects the short-term and long-term stability of the tunnel.