Creep Parameter Inversion and Long-Term Stability Analysis of Tunnel Based on GP-DE Intelligent Algorithm

Table 1

Creep parameters of the Cvsic model.

Sample	Axial stress (MPa)	Gk (GPa)	GM (GPa)	ηK (GPa·d)	ηM (GPa·d)
Gneiss	5	0.74	3.90	0.92	66.5
	10	0.53	3.56	2.71	192.61
	15	0.39	8.58	4.33	284.15
	20	0.28	9.72	7.06	442.98
	25	0.26	7.47	8.80	232.15