Tunnel Probabilistic Structural Analysis Using the FORM

Table 3

Results of deterministic analysis considering the mean values of random parameters (scenario 1).

Block code ()	Key-block geometry					Performance ()
	Volume () m^3	Joints area () m^2	Excavation face area () m^2	Joints trace length () m
0 0 0/UUU	0.1906	0.9486; 0.6044; 0.5544	1.3972	3.3441; 2.3024; 3.0437	∞ (stable)	∞
0 0 1/UUL	0.0098	0.0630; 0.2109; 0.0650	0.2768	1.0916; 1.7541; 1.3197	47.08	46.08
0 1 0/ULU	0.6032	1.1896; 1.3302; 1.9408	2.5946	3.8899; 3.5865; 4.3141	18.33	17.33
1 0 1/LUL	0.6032	1.1896; 1.3302; 1.9408	2.5946	3.8899; 3.5865; 4.3141	3.05	2.05
1 1 0/LLU	0.0098	0.0630; 0.2109; 0.0650	0.2768	1.0916; 1.7541; 1.3197	8.97	7.97
1 1 1/LLL	0.1906	0.9486; 0.6044; 0.5544	1.3972	3.3441; 2.3024; 3.0437	1.05	0.05

UUL: key block created by combination of 1st and 2nd joints upper half spaces and 3rd joint lower half space (based on BTM; see [6]).