Study on Dynamic Mechanical Properties of Bedding Shale Under Impact Load

Abstract In the actual mining process of shale gas, the loads and disturbances imposed on shale by man-made activities are a dynamic process. Therefore, the study of the dynamic constitutive theory of bedding shale under impact load has important theoretical value for the study of fracturing reformation of shale reservoirs and shale gas production. The objective is to explore the dynamic mechanical properties and fracture characteristics of shale with different bedding dip angles under medium and high strain rate loading. The split Hopkinson bar (SHPB) is used to conduct rock dynamic tests on shales with bedding dip angle of 0°, 30°, 60°, 90°. Based on fractal theory, we calculate the relationship between fractal dimension and broken fragments. The results show that the compressive strength and elastic modulus of shale change slowly when loaded at low strain rate, but when loaded at high strain rate, its compressive strength and elastic modulus increase significantly. The failure mode of shale is also transitioned from splitting failure at low strain rate to shear failure at high strain rate. Under high strain rate loading, the impact of loading rate on the dynamic mechanical properties of shale is greater than that of bedding dip. The mechanical behavior of shale under dynamic load is of great significance to the safe exploitation of shale gas and other resources.