Developing a Liquefaction-Related Protocol for the FEED Design Phase of a Pipeline RoW Corridor

Abstract

Soil liquefaction in the free field usually results in the generation of sand craters and volcanoes, as well as in surface ground cracks due to subsidence and lateral displacements. Technical constructions built on or within liquefiable soils may exhibit liquefaction-induced structural damages due to differential settlements, displacements and/or tilting that may lead to their loss of integrity or operational functionality. Oil and gas steel pipelines are typical examples of infrastructures for which appropriate mitigation measures against liquefaction-induced failures are required. For this reason, it is crucial to assess the soil liquefaction susceptibility along the pipeline Right-of-Way (RoW) and evaluate the deformations that may arise due to the occurrence of liquefaction. Since failure prevention and geohazard area avoidance is always preferable in comparison to the design of demanding mitigation measures of the application of post-failure retrofitting, the present study attempts to formulate a protocol that could: (a) be adopted for assessing the liquefaction potential of the various geological formations crossed by a pipeline RoW and, (b) be employed to assess the likelihood of the expected permanent ground displacement (PGD) along or across the proposed pipeline alignment. The proposed approach has been adopted for the studies performed regarding the Front-End-Engineering Design FEED phase of the onshore part of the Trans Adriatic Pipeline (TAP), which crosses the area of Greece and Albania. It is highlighted that this protocol offers a preliminary combined working approach that mainly integrates desktop study and field surveys that should be used for optimizing the pipeline route and define the distribution of the in-situ measurements.