In fact this is also my opinion. It is more likely that the vertical changes in direction combined with large thermal expansion cause the problem.
But I still need to prove that Euler buckling did not happened.
The pipeline is miles and miles in length. The pipe size is 8". No questions about shell buckling. It will not happen.
I know the soil characteristics and the spring rate for interaction with the pipe.
The level of stresses is under allowable but the axial buckling happened and the pipe popped...
In http://www.americanlifelinesalliance.org/pdf/ASCE_...
I found calculation for side wall crushing, and ring buckling. Nothing about axial buckling for buried pipe.
I have an 8" pipe size with soil around it.
The operating temperature is around 300F. I have large deflections and possibly large axial forces. The pipeline is restrained axially by friction and sometimes by natural or real anchors.
If the axial forces are high the pipe can buckle. The soil...