Mechanical Response of Castlegate Sandstone under Hydrostatic Cyclic Loading

Figure 8

Average peak volumetric strain of every five cycles during the tests. Tests conducted with 8-hour cycle rates are plotted against the cycle number (a) and time elapsed (b), while samples hydrostatically loaded with 4-hour cycle rates, 2-hour cycle rates, and no stress cycling are plotted against the cycle number (c) and time elapsed (d). CG_010 in (c) only shows the strain during cycling, while CG_010 in (d) shows both the initial static period (~5 days) followed by the initiation of stress cycling.

(a)

(b)

(c)

(d)