I am working a study for buried pipeline in a landslide (depth 1.8m). We’ve got 60 displacement points according a monitoring survey on this area.

We want to determine critical areas of the pipeline.

I have proceeded in the following way:

1. Modeling design path (buried piping with both ends fixes, virtual anchor).
2. Apply the 60 displacement vectors over the pipe. The assumption is that pipe moves following the landslide

According my results, for step 1 there are not overstress, but for step 2, I ‘ve got huge values of stress (2000% !!!)

Would you advice us the following please:

How to model this phenomenon?.

What tools should I consider?

CNODES . How apply them in this case?

Please, help me

Regards,

Carlos

Assuming the measurements are of the surface soil displacements, you could conservatively assume the displacements at depth are the same (they should be less) and apply the displacements to the soil spring, not to the pipe. You will need to add connecting nodes to each soil spring and a displacement field for each connecting node...it's a lot of work so make sure you have the soils modelled as acurately as you can, because if you 'rebury' the model you have to start over.

This isn't the intended use for the soil spring modelling so be aware you may be entering into the non-linear stress/strain range, as well as non-linear geometery (large displacements). For studies like this I keep my comments to either the pipe has yielded or not, don't report stress values above yield.

What is the criterial, the support teoric?, why use cnodes and not single displacement?.
I need undestand the reason, for me supported.
__________
Carlos GM

Hmm hard to explain that one in just words.

Read the Guidelines for the Design of Buried Steel Pipe, by ALA/ASCE.

Chapter 8 does an excellent job of explaining the technique.