Dynamic and Static Combined SHPB Experimental Study on the Mechanical Properties of Fractured Sandstone

To study the influence of fracture inclination angle on the dynamic mechanical properties of sandstone under dynamic and static combined loading conditions, impact compression tests were conducted on prefabricated fractured sandstone specimens with inclination angles of 0°, 15°, 30°, 45°, 60°, 75°, and 90° using dynamic and static combined SHPB test device. The results show that: Under dynamic and static combined loading conditions, the dynamic stress-strain curves of prefabricated fractured sandstone specimens with different inclination angles are located below the complete sandstone specimen curve. As the inclination angle of fracture increases, the dynamic compressive strength, dynamic strain, dynamic elastic modulus, and average particle size of fragments all show a variation of first decreasing and then increasing, and the inflection point is located at fracture inclination angle of 45°. When the fracture inclination angle is 0°, the failure mode of the specimen is tensile failure along the loading direction, while failure mode is tensile-shear composite failure for fracture inclination angle of 15° ~ 60° and shear failure for fracture inclination angle of 75° ~ 90°. Moreover, the fragmentation degree of the specimen is largest at fracture inclination angle of 45° and is smallest at 0°.