Influence of Rock Mass Discontinuity on Blast-Induced Vibration Attenuation in Quarry

This study investigates the influence of rock mass discontinuities on blast-induced ground vibration attenuation in a marble quarry in eastern Taiwan. A total of 53 blasts and 106 vibration records were collected and analyzed using image-based rock mass characterization with WipFrag (Version 4) software. Discontinuity conditions were quantified through the joint factor (JF), defined by the median size (D50) and maximum size (D100) from cumulative size distribution curves. The PPV (peak particle velocity) data were fitted using the USBM, Sadovsky, and a modified Simangunsong equation incorporating a discontinuity correction factor. The modified Simangunsong model yielded the highest correlation (R2 = 0.8632), followed by the Sadovsky (R2 = 0.8067) and USBM (R2 = 0.7674) equations, indicating improved in-sample fitting performance when discontinuity effects are included. The results show that explicitly considering discontinuity effects enhances the reliability of PPV estimates for the studied site and that highly fractured rock masses with smaller block sizes result in greater vibration attenuation. The study demonstrates that a practical approach to quantify discontinuities through image analysis and embedding them into empirical PPV attenuation models can be used to refine quarry blasting design for vibration control purposes.