Experimental Investigation on Sandstone Permeability under Plastic Flow: Permeability Evolution Law with Stress Increment

Table 10

Values of axial stress, confining pressure, axial strain, circumferential strain, and permeability.

State	(MPa)	(MPa)	(%)	(%)		State
1	12.43	6.00	0.147	0.011		Pre-peak
2	44.22	6.00	0.468	0.041		Pre-peak
3	63.24	6.00	0.628	0.070		Pre-peak
4	80.57	6.00	0.789	0.112		Pre-peak
5	97.34	6.00	1.109	-0.195		Shear yielding
6	40.65	6.00	1.124	-0.698		Plastic flow
7	53.25	6.00	1.140	-0.758		Plastic flow
8	44.56	6.00	1.116	-0.793		Plastic flow
9	48.85	6.00	1.229	-0.800		Plastic flow
10	35.56	6.00	1.125	-0.842		Plastic flow
11	34.42	6.00	1.109	-0.845		Plastic flow