Soil-Pipe Interaction in Subsea Pipeline Upheaval Buckling

Sub-sea pipelines are buried in shallow waters as protection against snagging by fishing lines, ship's anchors, andhydrodynamic forces. The soil cover provides resistance to upward movement of the pipe which is caused by thermallyinduced axial loading, a phenomenon known as upheaval buckling. A safe buried pipeline design must take into account a reliable evaluation of the pipe-soil interaction. The simulation of soil-pipe interaction must considerappropriate contact elements and pipe roughness, which is less investigated. In this paper the effects of pipe roughness and contact elements on soil response is investigated using finite element analysis. The frictional contact behavior varies between smooth to rough conditions and various friction coefficients are implemented. The soil uplift resistance toward pipe movement also is investigated and the normalized uplift force is calculated. In order to model large penetration, ALE method is used. The results reveal that pipe roughness considerably increases the amount of soil uplift resistance. Moreover, the findings suggest that a friction coefficient in the range of 0.3 to 0.7 can provide a good estimation for frictional behavior of the pipe-soil upward interaction

Keywords:

Subsea pipeline , Upheaval buckling , Contact elements , Uplift resistance , Roughness , Deep failure