# Study on Dynamic Mechanical Properties and Failure Pattern of Thin-Layered Schist
## 1 Introduction  
Stratified rock mass is a discontinuous medium with widespread distribution, characterized by macroscopic bedding. It can be classified into two primary types: metamorphic rocks (such as slate, phyllite, and schist) and sedimentary rocks (including shale, sandstone, and limestone) [1, 2, 3]. The mechanical characteristics of layered rock mass are relatively consistent parallel to the layer, while the mechanical properties perpendicular to the layer show significant differences. Due to the anisotropy of stratified rock mass, the failure mode and strength of rock mass in different directions will be different. Therefore, it is very important to master the mechanical properties, failure pattern and stratification effect for stratified rock mass [4, 5]. Numerous scholars have conducted research on the intricate mechanical properties of stratified rock mass. For example, [PERSON] et al. [6] investigated the macro and micro fracture behavior of laminated gneiss and discussed the influence of temperature and bedding angle on the tensile strength. [PERSON] et al. [7] revealed that acid treatment affects the failure pattern of layered limestone and found that there are three main failure modes with the change in bedding angle, namely split failure, sliding failure and mixed failure. [PERSON] et al. [8]explored the relationship between the fracture toughness and tensile strength of shale in relation to the bedding angle and anisotropy degree. [PERSON] et al. [9] conducted Brazil splitting tests and finite element simulations on shale to study how bedding and matrix influence tensile strength and fracture toughness. [PERSON] et al. [10] examined the mechanical properties of stratified rock mass along with four typical failure modes using simulated materials. [PERSON] et al. [11] utilized uniaxial and triaxial test methods to explore different coal samples' mechanical properties at varying bedding angles. The previous studies have primarily focused on the mechanical characteristics of layered rock formations under quasi-static loading conditions. However, during tunnel excavation and mining operations, these rock formations are predominantly subjected to dynamic loads. Therefore, it is essential to investigate the dynamic mechanical properties and failure pattern of stratified rock masses under impact loads [12]. Numerous scholars have made significant progress in exploring the dynamic mechanical features of stratified rock formations. [PERSON] et al. [13] studied the dynamic tensile strength of coal samples under saturated and dry water content conditions using Brazilian disk tension tests. [PERSON] et al. [14] put forward the energy dissipation parameter as an evaluation indicator to study the mechanical characteristics and deformation laws of rock under impact loads. [PERSON] et al. [15] examined the variations in mechanical parameters and failure modes of shale with different bedding angles at varying temperatures. [PERSON] et al. [4] investigated the dissipation of energy during the dynamic fracturing of layered coal rocks. [PERSON] et al. [16] utilized SHPB systems to comprehensively study the dynamic mechanics and absorbed energy of phyllite. [PERSON] et al. [17] performed dynamic triaxial SHPB tests on shales with different bedding angles by numerical simulation and revealed the stress-strain curve, failure process and morphological characteristics of layered shale. Schist is a metamorphic rock with a typical lamellar structure resulting from regional metamorphism. It is characterized by its schistity structure, consisting of lamellar, plate-like, and fibrous minerals arranged parallel to each other with a visible grain size. Due to its internal weak schistity plane, schist is generally considered a transversely isotropic material [18; 19]. [PERSON] et al. [20] conducted triaxial compression creep tests to explore the impacts of the foliation direction and stress level on mica schist's creep behavior. [PERSON] et al.