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

Table 5

Stress increment and strain increment during plastic flow of the rock sample.

Step	(MPa)	(MPa)	(%)	(%)			State
	-64.5	0	0.364	-1.23		-64.50	Unloading
	-7.97	1.25	-0.048	0.068		-15.63	Unloading
	3.24	-2.25	0.095	0.053		17.03	Loading
	-9.32	0.66	-0.095	-0.007		-13.37	Unloading
	4.64	0.24	0.048	-0.025		3.17	Loading
	-12.8	0	-0.24	0.209		-12.80	Unloading