A Dynamic Risk Assessment Method for Deep-Buried Tunnels Based on a Bayesian Network

Table 6

Nodes and node ranges.

Nodes	Node range
A1 section size	Medium			Large
A2 construction method	Center diagram method (CD)	Bench cut method (BCM)	Ring cut method (RCM)	Full face excavation method (FFEM)	Center cross diagram method (CRD)
A3 tunnel depth	<15 m		15~25 m	>25 m
A4 surrounding rock level	IV		V	VI
A5 groundwater	No water		Water leaking	Water gushing
A6 mud inrush	No mud		Mud leaking	Mud inrush
A7 prereinforcement effects	Good		Medium	Poor
A8 support timing	In time			Late
A9 construction quality	Good		Medium	Poor
A10 construction experience	Well experienced		Medium	Inexperienced
A11 construction management	Strict		Medium	Poor
A12 support strength	High		Medium	Low
A13 inner-tunnel observation	Normal		Slight cracks	Slip off
A14 arch crown convergence	III		II	I
A15 side wall displacement	III		II	I
B1 objective factor rating	I		II	III
B2 subjective factor rating	I		II	III
B3 monitoring factor rating	I		II	III
C1 dynamic risk rating	I		II	III