Abstract: Current research on impact-induced rock fragmentation primarily focuses on light- and medium-load conditions, while the energy consumption responses across diverse lithologies under heavy-load impacts remain underexplored. To address this gap, a self-developed multi-modal impact experimental system was employed to conduct combined single-cutter and continuous impact tests. This study elucidates the energy dissipation mechanisms and volumetric fragmentation evolution characteristics of sandstone (soft rock), limestone (transitional lithology), and granite (hard rock) under high-energy impact loading governed by impact velocity, frequency and energy. The research findings indicate that:(1) Single-impact experiments demonstrate that sandstone (soft rock) and granite (hard rock) initiate fracturing at impact energies exceeding >50 J, whereas limestone (transitional lithology) requires >75 J. The growth rate of impact crater diameter follows the hierarchy of limestone > granite > sandstone. Fragmentation volume exhibits distinct lithological trends, characterized by exponential growth in limestone and linear growth in sandstone and granite. Regarding specific energy, the energy efficiency of sandstone fragmentation decreases with increasing impact energy (positive correlation), whereas limestone and granite exhibit enhanced efficiency (negative correlation). Under continuous impact loading, sandstone split at an impact velocity of 2.41 m/s and a frequency of 9 Hz, while limestone developed cracks at 3.17 m/s and 21 Hz, and granite developed cracks at 3.62 m/s and 24 Hz; concurrently, the proportion of large-sized fragments in sandstone debris initially increased and then decreased, whereas this proportion continuously increased for the harder rocks (limestone and granite), and both limestone and granite exhibited a universal efficiency peak within the impact energy range of 40-100 J. (3) Elevated rock strength correlates with an increase in both the critical impact energy and the frequency thresholds. On this basis, an energy adaptation criterion is established:soft rocks necessitate low-energy, high-frequency loading to mitigate energy dissipation, whereas hard rocks require high-energy, low-frequency loading to facilitate volumetric fragmentation.

Key words: heavy-load impact rock breaking, continuous impact, particle size classification, fragmentation specific energy, deep hard rock

摘要： 目前冲击 破岩研究主要聚焦于轻载和中载冲击条件,但在重载冲击作用下不同的岩石属性冲击破碎能耗响应等研究还不充分。鉴于此,自主研发了多模态冲击实验系统,通过单齿-连续冲击耦合实验,揭示了砂岩(软岩)、灰岩(过渡岩性)、花岗岩(硬岩)在高能冲击载荷下(冲击速度、冲击频率、冲击功)的能量耗散机制与体积破碎演化规律。研究结果表明:①单次冲击实验表明砂岩(软岩)与花岗岩(硬岩)在大于50 J冲击功下产生裂纹(灰岩需大于75 J),冲击坑直径增速从大到小依次为灰岩、花岗岩、砂岩;不同岩性的破碎体积增长特征存在显著分化,灰岩为指数增长规律,而砂岩和花岗岩均遵循线性增长规律;破岩比功表明,砂岩的能耗效率随着冲击功的增加而降低(正相关),而灰岩和花岗岩的能耗效率则与冲击功呈负相关。②连续冲击中,砂岩在冲击速度为2.41 m/s和冲击频率为9 Hz时劈裂,灰岩在冲击速度为3.17 m/s和冲击频率为21 Hz时发生裂纹,花岗岩在冲击速度为3.62 m/s和冲击频率为24 Hz时发生裂纹;砂岩大颗粒岩屑占比先增后减,硬岩类持续增加;灰岩与花岗岩在40~100 J冲击功区间存在普适效率峰值。③岩石强度增加导致临界冲击功和频率阈值增加,并提出软岩适配低能冲击(防能量耗散)、硬岩适配高能 冲击(促体积破碎)的能量准则。

关键词: 重载冲击破岩, 连续冲击, 粒度分级, 破碎比功, 深部硬岩