Response Of Buried Oil/Gas Pipeline To Seismic Activity In A Slope Site

In Kenya buried pipelines are used for economic transportation of oil andnatural gas. Due to circumstances such as difficult terrain, the pipelines maysometimes be constructed in unstable slopes. In such situations, the owner of thepipeline has an intrinsic interest in guaranting that their pipeline would not rupture orbreak due to unstable soil movement.In this research, a steel pipe with a diameter of0.6m, a wall thickness of0.012m,a steel elastic modulus of2.1x1011Pa and a density of7800Kg/m3is selected forlongitudinal permanent ground deformation and inserted into the soil through thecontact elements target170and contact173. An El-Centro seismic acceleration wavewith peak ground acceleration of4.5m/s/s is input vertically along the pipeline andon the NS directions. Simulations are carried for20s with a time interval of0.02s.A buried steel oil pipe is considered as a structure for transverse permanentground deformation and its performance against a local slope is numerically analyzedby ANSYS program. A relative downward movement perpendicular to the pipe axisis considered. An elastic-plastic model is considered with guidelines provided for inASCE for cohesion-less (sand) soil. Then, some recommendation and probablemodifications are suggested to rehabilitate the buried pipe performance.