Nonlinear Viscoelastic-Plastic Creep Model of Rock Based on Fractional Calculus

Table 1

Creep parameter identification results.

Shear stress (MPa)	G (MPa)	η (MPa·mm^−1·h)	ξ1 (MPa·mm^−1·h^β1)	β1	ξ2 (MPa·mm^−1·h^β2)	β2	R^2
5.084	132.366	2.869 × 10^20	44.301	0.018			0.9958
8.132	135.856	2.108 × 10^25	51.949	0.024			0.9954
11.180	138.087	5.454 × 10^25	57.345	0.031			0.9967
14.228	139.375	7.411 × 10^27	51.804	0.034			0.9943
17.276	168.487	4.476 × 10^18	37.525	0.043	2.101 × 10^16	13.605	0.9928