UPHEAVAL BUCKLING ANALYSIS OF SUBSEA PIPELINE BY CONSIDERING THE EFFECT OF SEABED FRICTION USING THE POWER SERIES METHOD

In this paper, the upheaval-buckling problem in subsea pipelines due to the effect of friction of seabed soil is investigated. Subsea pipelines are commonly laidunburied. Initial unevenness in the topography of seabed or later under scouring either may result in free spanning and produces upheaval buckling in pipelines. Theabovementioned parameters can also cause serious harmful disasters. In order to evaluate the exact critical buckling loads of submerged pipelines, a numerical model based on power series expansions has been formed. In the proposed numerical method, the approximation function describing the buckling form of pipeline is derived by using the power series method and imposing the boundary conditions. The energy method is then used to evaluate the critical buckling load of subsea pipelines. One comprehensive example including of different types of pipelines are presented to verify the accuracy and validity of this method. The evaluated results are compared to the other available analytical methods. Upheaval buckling analysis of subsea pipelines has been the subject of many researches in the past decades [1, 2]. Some experimental studies on upheaval buckling of buried pipelines were performed by Maltby [3, 4] and Yaylor [5]. Croll [6] used Martinet analysis method and made progresson it for buckling analysis of a clamped column. The study on thermal upheaval buckling load of subsea pipelines by considering the effects of localized and geometricimperfections on stability of mentioned structures was done by Ju [6].