About Coupled Eulerian Analysis( pls help)

Hi!

Good Day.

Please note that I want to model a pipeline
which is on ground surface using CEL. I have applied the geostatic stess
only in step-01. But at the end of step-01, pipe is starting to move
upward. I do not apply any force on pipe but it seems to me that pipe
experienced some force which push it to move upward. Also, I do not
apply any gravity load for pipe.

Please advice.

Thanks in advance.

Sincerely-
sujan