Research Article

Dynamic Fracture Experiment of Fractured Rock under Dynamic Loading

Table 4

Crack propagation process of Specimen a1 at the loading rate of 19.7 m/s.

High-speed imagesCrack sketchStress (MPa)Loading time (μs)Crack propagation process

28.00
Prepeak
70.5White spots began to occur from the vertex of the prefabricated fracture of specimen, and microcracks occurred locally
35.97
At peak
106.4Cracks continued to propagate, and cracks gradually occurred from the ends of specimen
24.67
Postpeak
147.0More cracks occurred from the ends of the specimen, and cracks propagating from the vertex of the prefabricated fracture had increased width