Operational and geological parameters in the assessing blast induced airblast-overpressure in quarries

Airblast disturbances, like ground vibrations, are undesirable by-products of blasting. Airblast damage and annoyance are directly related to factors such as blast design, weather and terrain conditions, and human response. But, unlike blast induced ground vibrations, airblast impacts the structures through the roof, walls and windows leading to human annoyance. Because any structure rumbling and rattling, including blast induced vibrations can fuel the fear of people. The experiences on airblast-overpressure (AOp) measurements show that it is sometime impracticable to set a maximum AOp limit, with or without allowed appropriate percentile of exceedances, because of the significance and unpredictability of variable geological conditions and the restrictive character of this kind of limitations in blasting practice. We therefore utilized the method of modified scaled distances (SDs) based on empirical equations considering such factors as blasting parameters and geological parameters of rock mass for bench blasting in quarries. The aim of this application was to get an environmentally friendly and technically practicable results by using site specific SDs instead of conservative SD values. This method was realized in a quarry in Istanbul with numerous experimental shots. In these experiments, the levels of airblast-overpressures were investigated as a function of variable conditions. The results show that the performances of these estimations are governed by the site-specific character of these empirical relations.