Influence of geological condition and blasting pattern on the site specific parameters in PPV prediction model

The currently available blast vibration attenuation equations (AEs) usually only accurate for one-location database. The site specific parameters usually changes when the geological condition and blasting pattern changes. This paper is aimed to study the influence of geological condition and blasting pattern upon the AE’s parameters K and β. In order to achieve the research purpose, 8 blasting experiments were carried out. On each blasting experiment, a blast vibration device was set up on a rock surface and hooked up with a 120 m long coaxial cable consisting of a series of 8 geophones. The series of 8 geophones was positioned with respect to the geological condition and blasting pattern. The blasting revealed that the peak particle velocity (PPV) values were in the range of 0.0007 mm/s to 1.6175 mm/s. The frequencies corresponding to the PPV values varied from 4 Hz to 56 Hz, with dominant frequency in the range of 5 Hz to 10 Hz. The experiment suggest that the blast vibration which propagates deviating off the dip direction of the discontinuity plane at angle of less than 30° would be more affected by bench blasting direction as well as initiation sequence direction than the geological discontinuity characteristics. It was also confirmed that the K parameter was confirmed to be related to monitoring location toward bench blasting direction and diameter of blast-hole. Meanwhile, the β parameter was obviously more related to monitoring location toward initiation sequence direction and bench blasting direction rather than the transmitting medium condition.