Attenuation Of Blasting Induced Peak Particle Velocity: Constructing A New Empirical Formula

Blasting is considered as one of the most economical ways of producing aggregate by breaking rock mass in mines and quarries. However, blasting always induces unwanted vibrations to nearby civil engineering structures, such as buildings. For vibration controls, Peak Particle Velocity (PPV) is found empirically related to damages of buildings and, thus, is the commonly adopted parameter used in vibration monitoring and control. Since 1960s, a commonly adopted empirical formula for predicting PPV is expressed in terms of a power law of the so-called scaled distance (D), which is defined as D=R/W-1/2 with R being the distance of the observation station from the explosive source (in meter) and W being the maximum charge per delay (in kilogram of explosive). However, such empirical formula is dimensionally dependent (i.e. the empirical constant is unit dependent). In this study, a dimensional analysis was used in constructing a new dimensionless empirical formula for normalized PPV, taking explosion energy (E), duration time (t), density of the rock (rho) into account. Five hundred blast data from the Site Formation Project of the Anderson Road Quarry in Hong Kong were used for correlation analysis using both the traditional and the new dimensionless formulas. For the same set of 500 data, the new dimensionless formula gives a correlation coefficient value of 0.9509 whereas the conventional one gives a value of 0.7607, showing that the proposed formula is dimensionally correct and reflects velocity attenuation much better than the conventional one.