Buried pipelines subjected to ground deformation caused by landslide triggering

Abstract

Permanent ground deformation is one of the most damaging hazards for buried lifelines such as gas and oil pipelines. The most frequent cause of permanent ground deformation is a landslide. Landslides can be triggered by a variety of causes, yet the factors responsible for the most damaging landslides are water and especially earthquake. The scope of this study is to investigate the response of a continuous buried pipeline subjected to ground deformation caused by landslide triggering, considering two characteristic cases: (a) the pipeline running perpendicularly to the soil movement vector and (b) the pipeline is parallel to the soil movement vector. An idealized landslide of 3D geometry is considered. Due to the inconsistency between the colossal dimensions of the landslide and the much smaller pipe geometry (a combination that would call for a numerical model of several millions elements), the problem is decoupled. In the first step, a "global" free-field model is employed to simulate the landslide evolution, ignoring the presence of the pipeline. The free field analysis provides the input for the second step, in which a "local" detailed model of the pipeline, along with the surrounding soil, is used to simulate its distress. This allows the use of adequately large elements for the global model, and reasonably small elements for the local one, circumventing the aforementioned scale-related problem.