Predicting the risk of upheaval buckling (UHB) of buried subsea pipelines remains a challenge within the industry because of the many inherent uncertainties associated with this mechanism. In this paper, it is proposed to further evaluate the effect of the backfill on the overall pipeline response.
With the fast-paced development in pipeline engineering software tools, it is now possible to simulate upheaval buckling easily using an intelligent backfill soil spring (BFSS). In addition to the conventional pipe-soil interaction springs in the axial, lateral and vertical directions, the BFSS captures the interaction between the upheaval movement of the pipe and the backfill soil. With this respect, the behaviour of the backfill material can be properly modelled.
This paper first explains the implementation of an intelligent backfill soil spring (BFSS) and its applications to capture pipe-soil interaction behaviour for UHB analysis. Results are then compared with current available methods, i.e., the solution proposed by Palmer et al. (1990) and benchmarking with ABAQUS. Some key elements pertaining to UHB analysis will be highlighted. The comparison shows that using a backfill soil spring for UHB analysis gives confidence in the design because the behaviour of the backfill material can be clearly visualized.