Abstract: Rockfall describes the process in which rock masses or slope materials rapidly detach and move downslope under the influence of gravity, weathering, earthquakes, or other triggers. Such events are characterized by high randomness and concealment, often occurring suddenly, which makes advance prediction and effective prevention particularly challenging. Based on normal impact tests using rockfall simulant materials, this study investigates the relationship between dynamic fracture mechanisms and impact loading rates. The main conclusions are as follows: (1)During specimen fracture, multiple distinct cracks initiate first. With increasing impact loading rate, these cracks progressively propagate and interconnect, ultimately leading to complete specimen failure. Apart from the formation of a conical fragment in the impact zone at the base, the remaining debris is ejected and scattered in various directions. (2)An impact energy ratio α is proposed. Analysis of the collision process shows that as the impact loading rate increases, the growth rates of total kinetic energy before and after impact diverge. The impact energy ratio α gradually decreases, and its variation follows a power-law distribution. (3)Higher impact loading rates intensify specimen fragmentation, significantly increasing the newly created fracture surface area while progressively reducing the energy ratio α. This indicates that the creation of new surfaces consumes a portion of the energy during fragmentation. (4)The intensity of seismic signals increases with both impact velocity and specimen diameter. At the same time, as specimen diameter increases, the dominant frequency of the seismic signals exhibits a gradually decreasing trend.