Mechanical Properties of Sandstones under Initial Unloading Damage

Table 1

Compliance statistics of strain confining pressure.

Confining pressure (MPa)	Unloading capacity
	0.00	40.00%	66.67%	73.33%	80.00%	86.67%	93.33%	100.00%
12.5	100.00	0.080	0.106	0.118	0.145	0.162	0.196	0.337
13.0	93.33	0.070	0.082	0.096	0.120	0.146	0.189	—
13.5	86.67	0.067	0.078	0.091	0.117	0.142	—	—
14.0	80.00	0.067	0.078	0.085	0.115	—	—	—
14.5	73.33	0.063	0.072	0.084	—	—	—	—
15.0	66.67	0.063	0.072	—	—	—	—	—
17.0	40.00	0.060	—	—	—	—	—	—
20.0	0.00	—	—	—	—	—	—	—