Risk Assessment of Shield Tunnel Construction in Karst Strata Based on Fuzzy Analytic Hierarchy Process and Cloud Model

Table 6

Calculation rules for cloud numerical characteristic of quantitative indices.

Risk level	Ex	En	He
I	Ex1 = (0 + a)/2	En1 = (a − 0)/6	0.01
II	Ex2 = (a + b)/2	En2 = (b − a)/6	0.01
III	Ex3 = (b + c)/2	En3 = (c − b)/6	0.01
IV	Ex4 = c	En4 = En3	0.01