Data part, apply excavation time-steps

control_timestep 200 1.e-2 1.0
control_print 200 -time_current -post_node_rhside_ratio
control_mesh_delete_geometry 200 -excavation_0
control_mesh_delete_geometry_element 200 -quad4

control_print_data_versus_data 210 -time_current 0 0
-post_point_dof 0 -disx
-post_node_result 0 -velx

control_print_gid 220 -separate_index

We discuss here how the first excavation can be done in Tochnog; the other excavations are done quite similar, and you can find them in the input file tochnog/test/tutorial/tutorial_3.dat.

The control_timestep 200 records specifies that time steps of size $1.e-2 s$ should be taken until a time increment of $1.0 s$ has been done. This increment value of $1.0 s$ is arbitrary, since we do not use mass inertia in the calculation and so time is only a pseudo loading variable to specify the sequence of events in time. With control_print 200 we ask for printing of the current time in the calculation, and also the error ratio (see tutorial 1 for a discussion on the error ratio, or otherwise see the users manual). The -post_point_dof 0 -disx denotes that from all -post_point_dof records the one with index 0 should be used, and from that record the first value should be taken (numbering inside records starts of 0 in Tochnog). The -time_current 0 0 is a bit tricky: since there is only one -time_current record you need to specify a dummy 0 for the index, and the second 0 denotes again the first value in the record, so in fact the current time. Now the first excavation area as specified by the geometry quadrilateral excavation_0 is actually excavated by the record control_mesh_delete_geometry 200; record control_mesh_delete_geometry_element takes care that only quad4 soil elements will be excavated, we don't want to excavate the truss_beam elements (which are also located in the geometry quadrilateral).

control_reset_dof 330 -disx -disy

In the experiment the reported displacements are relative to the deformations after the second excavation. In the calculation this is obtained by the control_reset_dof record, which sets the displacements to null after the second excavation.