The Influence Mechanism of Conical Pick Wear on Rock Breaking Efficiency Based on Indentation Tests

With the deepening of mineral resource exploitation, conical picks are subjected to severe wear under high-stress and high-friction conditions, which has become a critical factor governing rock-breaking efficiency. To address this issue, this study systematically investigates the mechanism by which wear-induced geometric evolution of conical pick tips influences rock-breaking efficiency through controlled indentation tests. Three conical picks with varying wear degrees, characterized by different tip cone angles, were tested to quantify the peak indentation force, specific energy, indentation crater area, and indentation hardness index of rock specimens. The results show that progressive pick wear leads to tip blunting and an increase in cone angle, resulting in monotonic increases in peak indentation force, specific energy, indentation crater area, and indentation hardness index as functions of pick tip geometry. The experimental observations are interpreted using the cavity expansion model based on the Mohr–Coulomb yield criterion, following the Detournay–Huang theoretical framework. Wear-induced changes in pick tip geometry promote the expansion of the plastic zone and increase stress field complexity within the rock during indentation, thereby reducing rock-breaking efficiency. All reported trends are derived from repeated indentation tests and presented as mean values, demonstrating consistent and statistically reliable behavior. Based on these findings, optimizing pick tip geometry and improving wear resistance are identified as effective strategies to minimize energy consumption and enhance rock-breaking efficiency in deep hard-rock mining. This study provides a mechanistic understanding of how conical pick wear degrades rock-breaking efficiency through geometric control of plastic zone evolution, offering both theoretical insight and experimental evidence beyond previous material-focused studies.