Establishment of a Novel Fragmentation Prediction Model Incorporating Rock’s Response Time to Blasting

Rock’s response time to blasting (Tₘᵢₙ) refers to the critical time elapsed between the detonation of the explosive to the fragmentation and displacement of the rock, and it is a fundamental parameter that directly impacts blast-induced fragmentation. Although existing studies acknowledge the importance of this parameter, there are uncertainties regarding the factors determining Tₘᵢₙ. Furthermore, existing models use complex parameters, fail to demonstrate sufficient performance in different engineering scenarios, or are not suitable for use as a practical engineering tool. To address these uncertainties and to reveal the relationship between Tₘᵢₙ and fragmentation performance with an integrated model, a comprehensive dataset was obtained from 27 blasts conducted in 12 different quarries in Türkiye. The study followed a systematic methodology including geomechanical characterization, Tₘᵢₙ measurement via high-speed videography, and pre- and post-blast photogrammetric fragment size analysis. The findings enabled the development of a model that predicts Tₘᵢₙ with high accuracy (R² = 0.789, MAPE: %16.56) using parameters easily measurable in practice. More importantly, this estimation of Tₘᵢₙ was used in an integrated model where the mean fragment size (P₅₀) could be predicted directly and successfully (R² = 0.837, MAPE: %8.37), providing a significant contribution to the literature. In light of these results, the primary engineering contribution of the study is that it has developed a practical and reliable tool applicable in the field, which treats Tₘᵢₙ as an optimizable design variable and provides a seamless prediction framework from blasting design to the rock fragmentation.