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

Table 7

The weight of risk indicators.

The 1st-level indicators	Wi	The 2nd-level indicators	Wij
Human risk factors R1	0.2310	Physiological factors R11	0.2936
		Mental factors R12	0.3805
		Technical factors R13	0.3259
Machinery risk factors R2	0.3011	Improper installation R21	0.0976
		Machinery fault R22	0.4023
		Machines in disrepair R23	0.5002
Environmental risk factors R3	0.2200	Natural environment factors R31	0.3566
		Working environment factors R32	0.3250
		Social environment factors R33	0.3184
Management risk factors R4	0.2479	Management mechanism factors R41	0.3055
		Management organization factors R42	0.3868
		Safety management system R43	0.3077