Factor of safety in tunnels

To find the factor of safety in the tunnel with Flac 2D, would it be similar to the example that the program has for a slope with the command:
model factor-of-safety convergence 10…
or do other aspects have to be taken into account? because I get a very high factor

In theory that should work. Although I’m not sure why you would specify CONVERGENCE 10. I would just say MODEL FACTOR-OF-SAFETY and see what happens.