The Physicomechanical Deterioration Characteristics and Mesoscopic Damage Analysis of Sandstone under Acidic Environment

Table 4

Fitting parameters of relationship between the peak stress and the elastic modulus and soaking time.

Mechanical parameters	Soaking solution	a	b	c	R^2	Soaking solution	a	b	c	R^2
Peak stress (MPa)	pH = 1 H2SO4	40.916	−0.040	47.154	0.994	pH = 1 HCl	44.057	−0.035	43.783	0.986
	pH = 3 H2SO4	32.189	−0.042	55.909	0.991	pH = 3 HCl	37.846	−0.028	50.125	0.996
	pH = 5 H2SO4	27.477	−0.035	60.648	0.997	pH = 5 HCl	27.541	−0.038	60.607	0.996
	pH = 7 H2O	24.431	−0.021	63.477	0.992	—	—	—	—
	pH = 1 H2SO4	21.534	−0.023	2.857	0.992	pH = 1 HCl	22.677	−0.022	1.717	0.992
Elastic modulus (GPa)	pH = 3 H2SO4	19.151	−0.024	5.256	0.991	pH = 3 HCl	19.989	−0.022	4.427	0.988
	pH = 5 H2SO4	19.307	−0.017	5.552	0.960	pH = 5 HCl	19.082	−0.018	5.477	0.986
	pH = 7 H2O	20.604	−0.009	3.858	0.994	—	—	—	—	—