The dynamic fracture behavior of rocks subjected to impact loading is a fundamental issue within the field of rock dynamics. This study aims to construct microstructure models of heterogeneous minerals representative of various typical rocks and establish a coupled SHPB impact simulation system with FLAC-PFC to examine the mechanisms of fracture, energy dissipation law, and the characteristics of acoustic emission (AE) responses in rocks acted upon by impact loads. The main results obtained reveal the following: (i) The fracture mechanisms of various lithologies under impact loading exhibit common characteristics, predominantly behaving as composite failure mechanisms. The observed distribution characteristics are mixed and interwoven with shear-tension-implosion failures, with a tendency to aggregate from the boundaries towards the interior of samples. (ii) The AE fracture strength of various lithologies predominantly ranges from −8.25 to −5.25, with peak frequencies observed between −7 to −6. The sequence of AE-based B-values, ranked from highest to lowest, is as follows: red sandstone > green sandstone > slate > granite > blue sandstone > basalt. (iii) The T-k distribution for various lithologies follows CLVD (+)-first. (iv) A significant correlation exists between the energy-time density and the B-value. Rocks exhibiting high energy dissipation capacity are characterized primarily by small-amplitude AE events and small-scale fractures, whereas those with low energy dissipation capacity are mostly marked by large-amplitude AE events and large-scale fractures. These research findings provide a fairly solid theoretical basis for understanding the fracture mechanisms and energy dissipation behaviors of rocks subjected to impact loading.

Laminated rock bodies are prevalent in engineering applications, making the investigation of their damage characteristics and evolution patterns under impact loading critical for ensuring engineering safety. Despite this importance, the relationship between energy dissipation and the crushing mode of laminated rock bodies remains underexplored, particularly regarding the influence of lamination orientation on their dynamic response. To bridge this scientific gap, this study conducts rock impact tests in the presence of various lamination angles (0°, 30°, 60°, and 90°) and employs digital image correlation (DIC) technology alongside acoustic emission (AE) monitoring and fracture sieve analysis to systematically examine how lamination orientation affects energy dissipation patterns, crack propagation behavior, and fragmentation characteristics in rocks. The results indicate that the lamination angle has a significant influence on the energy dissipation characteristics of rocks. When the lamination orientation is parallel or perpendicular to the direction of shock wave propagation, the rocks exhibit a low intensity of energy dissipation, a singular crushing mode, restricted crack propagation, and a relatively stable fragmentation process. Conversely, laminated rocks with oblique intersections demonstrate complex damage modes due to the combined effects of shear and tension, wherein significant large-scale crack propagation occurs, exacerbating structural instability. Analysis of AE b -values corroborates these observations, revealing that the development of microcracks in rocks with diagonally interbedded laminations along the impact direction is more prone to result in large-scale destabilization and damage. This study elucidates the damage mechanisms and directional characteristics of laminated rocks subjected to impact loading, thereby providing a vital theoretical foundation and technical support for the safe design of engineering structures and related construction practices.

To investigate the mechanical behavior and energy evolution characteristics of various rock materials under impact loading, dynamic impact tests were conducted on five representative rock types using a split Hopkinson pressure bar (SHPB) apparatus, combined with X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The dynamic mechanical response, energy characteristics, mineral composition, and associated microstructural features of these typical rocks were systematically analyzed. The results show that basalt exhibits the highest peak strength, followed by blue sandstone and granite; all three display typical brittle failure characteristics, whereas red sandstone and green sandstone demonstrate greater ductility and plastic deformation capacity. By introducing the energy-time density index, the energy-time density of the rocks ranks from strongest to weakest as follows: green sandstone, red sandstone, granite, blue sandstone, and basalt. An innovative dynamic strength–energy-time density mapping model was established to elucidate the clustering and distinguishing characteristics of these rock materials. Assay results and mesoscopic images confirm the relationship between mineral composition and the fine structure of rock fragmentation mechanisms, highlighting that the critical transition from intergranular to transgranular fracture is the key mechanism governing impact pulverization. Furthermore, fractal analysis reveals that higher fractal dimensions are associated with more complex microcrack structures and may correlate with the corresponding energy dissipation intensity. These findings provide profound insight into the failure mechanisms of rocks under dynamic loading, offering significant theoretical value and engineering application prospects, particularly in fields such as mining excavation and rock mass stability assessment.