Optimization of Initiation Positions for Blasting in Jointed Rock Masses Based on Multi-Criteria Evaluation of Blasting Performance

The initiation position should be matched to the joint characteristics of the rock mass to improve blasting performance. Nevertheless, bottom initiation remains the conventional choice in engineering practice, despite limited understanding of how the relative performance of initiation positions varies with joint conditions. In this study, a comprehensive LFPP–TOPSIS-based evaluation method was established by integrating six blasting-performance indices. Its application was illustrated using intact rock blasting simulations, and the resulting ranking was assessed for qualitative plausibility. It was then applied to discrete element simulation results covering 12 joint dip angles and 7 initiation positions. Under the selected indices, weights, and simulated conditions, conventional bottom initiation does not always obtain the highest evaluation score. Offset top initiation and two-point initiation generally rank higher at small to medium joint dip angles, whereas bottom or offset bottom initiation ranks highest at large joint dip angles. A possible mechanism linking initiation position adjustment to blasting performance in jointed rock masses is further discussed. This study provides a numerical basis for comparing initiation-position preferences within the investigated joint conditions.