Abstract:

The presence of joint surfaces in rock masses primarily causes the attenuation of shock stress waves, leading to reduced explosion energy and blasting effectiveness. To investigate the dynamic mechanical properties, stress wave transfer law, and energy transfer law of granite with different joint dip angles under low strain rate impact loads, impact tests were conducted on jointed granite using the split Hopkinson pressure bar (SHPB) device. The tests involved three different impact pressures and four different dip angles. The results indicate that: (1) In rock samples with joints, the peak stress decreases with the increase of joint dip angle and increases with the increase of impact load. (2) The transmission coefficient initially increases and then decreases with increasing joint dip angles, and initially decreases and then increases with increasing impact load. (3) The energy transfer coefficient initially increases and then decreases with the increase of joint dip angle. For intact rock samples and rock samples with joint dip angles of θ = 0º and 45º, the energy transfer coefficient decreases with the increase of impact load. For rock samples with joint dip angles of θ = 15º and 30º, the energy transfer coefficient of first decreases and then increases with the increase of impact load.

Key words: dip angles, jointed granite, SHPB impact test, dynamic response, low strain rate