A PRACTICAL STUDY ON THE AIR-SHOCK CONTROL IN URBAN MOTORWAY SLOPE EXCAVATIONS BY BLASTING

Abstract

Blasting and mechanical excavation systems are the main methods used in the excavation of rocks masses in mining and construction works. Mechanical excavation is insufficient in the case of very hard rocks masses. Therefore, blasting is widely preferred for the excavation of hard rock masses. Environmental parameters such as ground vibrations, air-shock and fly-rock occur due to blasting. The magnitude of these parameters depend on the explosive per delay, distance between the measurement- and blasting points, geology and topography, blasting technique and blasting design. In this study, blast-induced air blast measurements were carried out at the same ground level as the blasting point and upper ground level point than the blasting point. Blastings were performed for the excavation of an urban motorway slope. Sand-bags were placed as barriers on the blast holes and capsules to investigate whether the air-shock levels could be reduced. Application of sand-bags was seen to reduce the frequencies of air-shock waves at the same- and upper level points. When the amount of explosive increased up to 2.67 times, air-shock levels only increased by 4.38% at the same level and by 5.51% at the upper level. However, frequencies of the air-shocks significantly decreased by 54.55% at the same- and by 48.51% at the upper level. This study suggests that the use of sand-bags as a barrier can significantly reduce the effects of blast-induced air shocks.