Experimental Investigation of Block Fracture Influence on P-Wave Propagation in Block Rock Mass

This article experimentally investigates the characteristics of $$P$$ -wave propagation in block rock mass when blocks fracture transversely and longitudinally. The velocity of $$P$$ -wave, rock block acceleration, kinetic energy, displacement response, and the time–frequency response of rock block were analyzed. The results show that when the rock block fractures, the $$P$$ -wave velocity decreases, the acceleration response duration time increases, and the maximum acceleration and kinetic energy decrease. However, transverse fractures show a more evident decrease in the acceleration and kinetic energy near the fracture area, and longitudinal fractures show a more evident decrease in the displacement amplitude far from the fracture area. On transverse fractures, the dominant frequency of acceleration and kinetic energy leads to a low value near the fracture area, but the dominant frequency of displacement—to a high value. Longitudinal fracture leads to a dominant frequency of block response occurrence time delayed far from the fracture area.