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

Table 1

Statistical table of the causes of safety risk accidents.

The accident causes	Frequency	Influence factors	Specific reasons
Mechanical injury	11	Human factors	Without certification
			The lack of awareness of security
		Machinery factors	Machines in disrepair
			Improper installation
		Environmental factors	Harsh working environment
		Management factors	Managers neglect their duties
			Imperfect site management
Ground collapse	48	Human factors	Inexperience
			Inadvertent operation
			Low technical capacity
		Machinery factors	Machinery fault
			Improper installation
		Environmental factors	The complex geological and working environment
		Management factors	Managers neglect their duties
			Imperfect management mechanism
			Unsound safe management system
Water gushing and mud-bursting	17	Human factors	Violation operations
			Inadvertent operation
		Machinery factors	Machinery fault
		Environmental factors	The complex geological environment
		Management factors	The lack of awareness of security management
			Irrational organizing structure
Gas leakage and explosion	18	Human factors	Inadvertent operation
			Lack of ability to identify hazards
		Machinery factors	Equipment aging
			Machines in disrepair
		Environmental factors	Unpredictable environment factors
			The complex social environment
		Management factors	Imperfect site management