Dynamic Mechanical and Water Saturation Softening Characteristics of Phyllite under Impact Loading

To study the influence of saturation on dynamic mechanical behavior and energy absorption in layered phyllite, phyllite specimens with varying bedding angles (0°, 30°, 60°, 90°) and moisture conditions (dry versus saturated) were prepared, and then a dynamic impact test was carried out by using the Split Hopkinson Pressure Bar (SHPB) test system. Finally, the mechanical properties and energy absorption characteristics of the specimens under varying bedding angles and saturation levels were analyzed. The results show that the deformation and failure mode of phyllite are influenced by the combined effects of bedding dip angle and moisture conditions. The mechanical parameter variation follows the sequence 0°>90°>30°>60° for bedding angles, with saturated specimens exhibiting lower values than dry specimens. Specimens predominantly exhibited crushing failure at 0° inclination, shear failure along bedding planes at 30° and 60°, and compressive bar instability at 90°, while showing higher degrees of fragmentation under saturated conditions. Experimental results demonstrate that saturated phyllite specimens exhibit higher energy dissipation density across all tested bedding angles compared to dry specimens, with maximum energy absorption occurring at 0° inclination angle and minimum dissipation observed at 90° inclination angle.