Multiparameter Inversion Early Warning System of Tunnel Stress-Seepage Coupling Based on IA-BP Algorithm

Table 1

Rock mass parameter table.

Parameter	E (GPa)	c (MPa)	ϕ (°)	K (10^−7 m/s)	A (10^−21)	n
Range	30∼50	2.5∼3.3	26°∼30°	1∼10	2∼4	0.5∼2.5