Pipeline lateral buckling initiated by the imposed residual curvature method with nonlinear pipe-soil interaction

In order to release the axial compressive force induced by high-temperature difference, the residual curvature method is one of the promising buckle initiation methods to initiate subsea pipeline to buckle in a controlled manner. This paper proposes a mathematical model to study pipeline lateral buckling initiated by an imposed residual curvature with nonlinear pipe-soil interaction. Two jumps, i.e., snap-through buckling and mode transition between modes 1 and 3, may appear during the process of lateral buckling for subsea pipelines when considering the residual curvature and the nonlinear pipe-soil interaction simultaneously. The influence of the lateral breakout resistance and the residual curvature on the buckling behaviour and the critical temperatures of snap-through and mode transition is analysed. The results show that the mode transition is controlled by the lateral breakout resistance. The jump between the pre-buckling and the post-buckling states is controlled by both the lateral breakout resistance and the residual curvature. The snap-through buckling phenomenon can be avoided by reducing the lateral breakout resistance, or by increasing the amplitude of the residual curvature, or by reducing the length of the residual curvature. The mode transition phenomenon can be restrained by reducing the lateral breakout resistance.