In-service hydrocarbons must be transported at high temperature and pressure to ease the flow and prevent solidification of the wax fraction. A pipeline containing hot oil will expand longitudinally on account of the rise in temperature; and if such expansion is resisted

for example by frictional affects over a kilometer or so of pipeline

compressive axial stress will be set up in the pipe-wall. The compressive forces are frequently large enough to induce vertical buckling of buried pipelines

which can jeopardize the structural integrity of the pipeline. In this paper

a theoretical solution of the vertical buckling has been introduced

with regards to the isolated prop initial imperfection cases of the submarine pipelines. Analytical tools are applied to predict the occurrence and the consequence of in-service buckling of a buried heated pipeline in Bohai oil field. An evaluation of this pipeline behaviour has been performed in order to ensure the pipeline structural integrity during operation in demanding loading conditions. The analysing results show that the upheaval buckling is most likely to occur from initial imperfection of the pipeline and the larger the initial imperfection amplitude

the less the axial force required for the upheaval buckling. The dynamic snap will happen for small initial imperfection amplitude. Trenching-burial is one kind of valid protection measures preventing the pipeline from thermal upheaval.