Experimental Study on Physicomechanical Properties of Deep Sandstone by Coupling of Dry-Wet Cycles and Acidic Environment

Table 4

Variation of k value of sandstone specimen under different conditions.

Stage of A-W-D cycles	pH = 4	pH = 5	pH = 6	pH = 7
	k	k	k	k
Stage I	0.960	0.970	0.974	0.983
Stage II	0.938	0.953	0.965	0.974
Stage III	0.899	0.923	0.935	0.953
Stage IV	0.849	0.886	0.905	0.924