pipeline stress analysis

HI ,
I am beginner with caesar II , I need help because I am not sure that my job is safe.
I analyse pipeline leaving on the groud ( oil) and i am using loop each 700 m , when I check the displacement ,caesar gives 100 mm , but during operation the diplacement are more than 2 meters ???
another problem with buried pipeline , can some one tell me why the pipeline go up even it's underground...solt is sand 1 meter depth?
please can someone help me for this case , and normally during construction what we need to known for safety construction.
regards

It is my request. better u discussing with ur senior engineers.

Hi,
Me too a fresher in this field, can be called as a trainee, but traning period almost over, so...

As for yur Qustion, that y buried pipelines become unburied over time.. the one solution to this can be "upheaval buckling" phenomenon.

Ric

I have actually no experience about pipeline but I've read something about "thermal ratchet". I don't know if this is the cause of the 2 meters movement. If your loop is buried underground(I don't know if I interpreted your question correctly), maybe the 100 mm movement was accumulated up to 2 meters through repeated "cool down" and "heat up" of pipe. "Thermal ratchet" can be developed if the pipe moves and create a void, then possibly the soil will collapse filling that void. During "cool down" the pipe will not go back to it's original position because it will be restraint by the soil that fills the void, and maybe the soil that collapse is stiffer than the original soil. Then as the pipe is expanding in only one direction the movement is accumulated. This is only a "wild guess" and only one of the "many possibilities"....If the pipe moves 2 meters this will create a huge force and maybe this is the cause why the pipe goes up above ground...Again this is only one of the "many possibilities"....


Cheers to all,

You have to explain very well what u are trying to tell. 700m of a straight pipeline without any bend is too long, be clear on your problem and send it down. u can paste the model so we can see. also ur operating or design conditions, materials and pipe thickness. let see if we can save ur job.