We've had a few users question the theoretical background on this Overburden Compaction Multiplier (OCM). This is a CAESAR II term and does not have basis in theory.

We have it in CAESAR II because it provides additional user adjustment to the transverse stiffness properties of the soil-pipe interaction. As Rich mentioned, we default to OCM=8 and that can be used with the ratio of the pre- & post-overburden densities. For example, if you put half the soil back on top of the pipe in the trench, then the ratio is 0.5 and you may want to use an OCM of 4. Again, this is an additional multiplier on transverse (not axial) stiffness values.

If you have your own soil stiffness and load limit values, you can enter them directly in the CAESAR II soil modeler.