Research on Coupling Degree Model of Safety Risk System for Tunnel Construction in Subway Shield Zone

Table 9

The efficacy value of risk indicators at all levels.

The 1st-level indicators	Ui	The 2nd-level indicators	Uij
Human risk factors R1	0.4008	Physiological factors R11	0.3250
		Mental factors R12	0.4300
		Technical factors R13	0.4350
Machinery risk factors R2	0.4174	Improper installation R21	0.4700
		Machinery fault R22	0.4200
		Machines in disrepair R23	0.4050
Environmental risk factors R3	0.4629	Natural environment factors R31	0.5300
		Working environment factors R32	0.4900
		Social environment factors R33	0.3600
Management risk factors R4	0.4097	Management mechanism factors R41	0.3850
		Management organization factors R42	0.4050
		Safety management system R43	0.4400