Data part, apply safety factor calculation time-steps

control_timestep 40 1.e-4 1.0
control_timestep_iterations_automatic 40 1.e-3 1.e-5 1.e-2
control_print 40 -time_current -post_node_rhside_ratio
control_print_history 40 -post_point_dof 10 -disy

control_print_gid 50 -yes

Look first back at the material definition where the friction angle and cohesion are lowered between time 1 and time 2. We will now use time-steps to determine where between time 1 and 2 the slope becomes unstable. The records control_timestep 40 with control_timestep_iterations_automatic 40 together define automatic time-steps, which will be taken till instability occurs. The record control_timestep defines an initial timestep of 1.e-4 and total time increment of 1.0. The record control_timestep_iterations_automatic specifies that the maximum allowed value of the error ratio -post_node_rhside_ratio is 1.e-3, the minimum allowed time-step size is 1.e-5 and the maximum allowed time-step size is 1.e-2. Tochnog will decrease the time-step size if that is needed to keep the error ratio below 1.e-3. If that is not possible anymore, due to instability caused by low friction angle and cohesion, the calculation is terminated. Later we will discuss how, using the current time of the terminated calculation, the safety factor can be calculated.