Mechanical and Acoustic Emission Characteristics of Sandstone through Triaxial Unloading Test after Cyclic Freezing-Thawing Treatment

Figure 6

The exterior surfaces of sandstone samples after different freezing-thawing cycles (a) 0, (b) 20, (c) 40, (d) 60, (e) 80, and the corresponding ones after triaxial unloading test (f–j).

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)

(i)

(j)