Table 3.

Model parameter identification results in the unloading condition.

Confining pressure (MPa)	Time period	G2 (MPa)	η1 (MPa·h)	G3 (MPa)	λ	η20 (MPa·h)	R2
4	After level 1	2.8116	10.6995	0.0280	1.4628	0.0330	0.9985
	After level 2	5.0531	14.8730	0.1549	25.2962	0.0080	0.9990
	After level 3	12.0426	18.1450	0.5411	24.9442	0.0246	0.9939
	After level 4	3.8941	11.0090	0.2865	11.4404	0.0173	0.9849
8	After level 1	7.8248	5.0745	0.1941	1.4831	0.2162	0.9934
	After level 2	10.1660	9.3348	0.4349	13.8946	0.0445	0.9951
	After level 3	3.3233	3.2988	0.0023	4.5079	0.0008	0.9983
	After level 4	8.9977	15.6245	0.0003	27.4785	0.0001	0.9907
12	After level 1	3.2486	2.8257	0.4599	8.0931	0.0584	0.9909
	After level 2	5.9537	4.1234	0.7569	10.7438	0.0822	0.9838
	After level 3	18.2933	28.5893	0.1578	23.0808	0.0133	0.9902
	After level 4	16.8359	21.1461	0.8046	22.0334	0.0520	0.9928