Laboratory Investigation on the Effects of Natural Fracture on Fracture Evolution of Granite Exposed to Freeze-Thaw-Cyclic (FTC) Loads

Figure 17

The main frequency characteristics of the tested samples during fracturing. (a–d) The sample IDs are NFG-34, NFG-24, NFG-21, and NFG-30, respectively. The corresponding natural fracture volume ratios are 0.19%, 0.15%, 0.13%, and 0.11%, respectively.

(a)

(b)

(c)

(d)