PFC2D-Based Analysis of the Effect of the Axial Loading Rate on the Mechanical Properties of Backfill
Table 3
Backfill destruction mode at different loading rates.
Axial strain (mm/s)
2e − 3
2.5e − 3
3e − 3
3.5e − 3
4e − 3
Analysis of the law of destruction
0.1
The model fails mainly through tensile failure. Over time, the tensile strain reaches a peak, and the specimen is violently destroyed
1
The compressive strength of the model increases, and the crack develops slowly compared with that at 0.1 mm/s. After reaching the peak strain, the crack rapidly develops
10
Tensile failure occurs, and the cracking stress increases. After the peak strain is reached, the crack rapidly develops
50
The crack distribution gradually densifies, no longer limited to the axial direction. The destruction mode is tensile failure accompanied by shear fracture
100
Tension failure is accompanied by secondary fracture. The destruction is more severe at high speeds, and the cracks are densely distributed
