Tunnel Probabilistic Structural Analysis Using the FORM

Table 1

Properties of the circular tunnel.

Deterministic parameters		Probabilistic parameters
Parameter	Value	Parameter	Distribution
	0°, 0°	/°	Normal (μ = 30, σ = 5)
	2.5 m	/°	Normal (μ = 25, σ = 3)
	0 KPa	/°	Normal (μ = 55, σ = 7)
	2.7	/°	Normal (μ = 110, σ = 5)
	0	/°	Normal (μ = 70, σ = 4)
Support	No support	/°	Normal (μ = 240, σ = 7)
		/KPa	Truncated normal (μ = 20, σ = 11) ≥0
		/°	Log-normal (μ = 30, CoV = 0.07)
		Ten/KPa	Uniform (0–8)

: dip of th joint set; : dip direction of th joint set.