Offshore pipelines and ice gouge geohazards: comparative performance assessment of decoupled structural and coupled continuum models

Abstract

Offshore pipelines in ice environments may be subjected to unique geohazards such as seabed ice gouging. These events involve nonlinear processes including large deformations and strains, contact mechanics, and failure mechanisms. Current pipeline engineering design practice employs decoupled, structural finite element modelling procedures to assess system demand and capacity. The inherent error and uncertainty within this approach drives conservative engineered solutions. Physical modelling and continuum numerical simulation tools complement this engineering framework to improve confidence in predicted outcomes. The relative performance of engineering models, used in current practice, and numerical simulation tools, including structural and continuum finite element modelling procedures, to predict the deformation and strain response of a buried pipeline subjected to an ice gouge event is examined. Refinements to the numerical modeling procedures and establishment of a consistent and compatible reference framework for the performance evaluation differentiate this study from others, which are subsets of the current investigation. For the parameter analysis conducted, within an equivalent reference framework, the outcomes demonstrate key factors, including superposition error and directional load decoupling, that influence model error that may not be as significant as previously considered. The scope and extent of this outcome is not fully understood and requires further investigations to delineate the significance across a wider parameter range.

Performance of Corrugated Steel Culverts Buried in Shallow Cover Depth and Subjected to Environmental Deteriorations

“…are not influenced across the range of parameters investigated. The numerical simulations suggest a transition in the culvert mechanical response related to the cover depth, which is consistent with current practice, analysis and research studies on the behaviour of buried structures (Pike and Kenny, 2016, Roy et al, 2015, Roy et al, 2018.…”

“…The continuum finite element modeling procedures were developed using Abaqus/Standard 6.13 software and adopted the same approach as the verification procedures. For soil/structure interaction problems, including energy pipelines, lifelines and culverts, the cover depth has a significant influence on the soil stress, load transfer processes and failure mechanisms , Roy et al, 2015, Pike and Kenny, 2016, Roy et al, 2018. In this study, the culvert was placed at different cover depths, 450 mm (H/Dv=0.…”

Upward Pipe–Soil Interaction for Shallowly Buried Pipelines in Dense Sand

“…Pipelines embedded at 1 ≤̃≤ 4 in dense sand are the focus of the present study, although it is understood that in some special scenarios ̃ could be outside this range, for example, for surface laid offshore pipelines in deep water (Dutta et al 2015) or the pipelines in ice gouging areas (Pike and Kenny 2016).…”