Causes of Delay in the Construction Projects of Subway Tunnel

Table 2

Possible ranges and impact degrees for the severity index.

Range	Impact degrees
R = 0	No influence
0 ≤ R < 20	Very low
20 ≤ R < 40	Low
40 ≤ R < 60	Medium
60 ≤ R < 80	High
80 ≤ R ≤ 100	Very high