A Complete Method to Safeguard the Buried Pipelines Subject to Landslide Effect Available to Purchase

Oil pipelines, whose layout interferes with geologically unstable areas, are subject to the stress caused by the displacement of the soil. In these conditions it is necessary to perform interventions aimed at ensuring the safeguard of the pipelines and of the surrounding environment. The reconstruction of the landslides system active on slopes and its monitoring is at the basis of the study related to the interventions to be done to defend the pipelines; at the same time, the control of the strains occurred directly on the pipes, through the use of strain gauges, provides a framework of the stresses generated on them. The knowledge of the strains occurred on the pipelines and the study of the interaction between soil and structure, through a Finite Element Modelling (FEM), allow the reconstruction of the stressing state of the pipes, in the absence of landslide and the contribution of forces transmitted from the soil to the pipelines. In the realized Finite Element Model, it has been possible to identify the weakest points of the pipelines, such as welded joints, to which have been assigned thresholds to be used as reference while monitoring the pipelines. When the stress accumulated on the pipes gets closer to such thresholds, it is possible to intervene by bringing to light the pipelines, by determining a release of accumulated tensions on them. Such intervention ensures the integrity of the pipelines and avoids oil spill phenomena in order to guarantee the protection of the surrounding territory. In this article it is presented a case study related to three in-operation flowlines, interfering with five different landslide blocks. The procedure for the carried out interventions is presented, together with the results of the modelling performed by associating the results of a ten-year monitoring active on such pipes. Results were presented about the stressing release determined on the section of pipes falling within one out of the five landslide blocks.