Sometimes underground pipelines are exposed due to vertical scour or lateral migration of streams (or other erosion). One option is to lower the (in-service) pipeline to a new depth that provides sufficient ground cover.
How can I determine the mechanical stresses on the pipe, and determine how much the line can be lowered? Also required is determining what length of trench will be required to accommodate the lowering. What are the relevant codes or standards?
This question is in relation to steel pipelines for both gas and liquids.