Is it ok to modal Buried pipe with differential settlement as Restraints with Gap in +Y
Please give your opinions and suggestions.

Many thanks

You will need to model your pipe and then run the buried modeller function. Once you have done that you will need to apply cnode displacements in the new buried model at the points where you expect settlement to occur. This is time consuming and annoying when you have to remodel pipe routing (or if you want to put in more break elements), but as far as I know, it's the only way.