Upheaval buckling of offshore pipelines buried in loose and liquefiable soils
<p>Pipelines used for the transportation of oil and gas products offshore are often buried beneath the seabed for protection from mechanical damage and for thermal insulation. During high temperature and high pressure operations, these pipelines are susceptible to resurfacing behaviour known a...
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| Formato: | Thesis |
| Idioma: | English |
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2014
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| _version_ | 1826315657711452160 |
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| author | Williams, E Elizabeth S. Williams |
| author2 | Byrne, B |
| author_facet | Byrne, B Williams, E Elizabeth S. Williams |
| author_sort | Williams, E |
| collection | OXFORD |
| description | <p>Pipelines used for the transportation of oil and gas products offshore are often buried beneath the seabed for protection from mechanical damage and for thermal insulation. During high temperature and high pressure operations, these pipelines are susceptible to resurfacing behaviour known as <em>upheaval buckling</em>, a structural response that is strongly influenced by the resistance of the surrounding soil. Despite much previous research on pipe uplift, the influence of the initial soil state – particularly in loose and liquefiable soil conditions – on the uplift resistance and corresponding buckling behaviour of the pipe is not well understood.</p> <p>This thesis presents research that examines the implications of these backfill conditions in the context of the global behaviour of the pipeline. The work consists of plane-strain monotonic uplift experiments focusing on density, rate, and stress level effects on the initial pipe-soil response. This is followed by numerical modelling of the global buckling behaviour using the experimental data as inputs. Finally, plane-strain cyclic experiments examine the possibility of progressive upward displacements over a number of cycles causing eventual upheaval buckling.</p> <p>A key finding from the uplift tests is that very loose backfill conditions may result in a localised flow-around failure mechanism, associated with lower peak resistance and a softer force-displacement response than with the sliding block mechanism that is typically assumed. This leads to lower peak buckling loads/temperatures than those predicted by current design guidelines. High quality data from both the monotonic and cyclic experiments was used to assess and suggest improvements to design guidance for these conditions.</p> |
| first_indexed | 2024-03-06T18:52:35Z |
| format | Thesis |
| id | oxford-uuid:10c2cf4d-ab26-4f2c-82d9-35e15cfa03bc |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-12-09T03:30:06Z |
| publishDate | 2014 |
| record_format | dspace |
| spelling | oxford-uuid:10c2cf4d-ab26-4f2c-82d9-35e15cfa03bc2024-12-01T13:27:40ZUpheaval buckling of offshore pipelines buried in loose and liquefiable soilsThesishttp://purl.org/coar/resource_type/c_db06uuid:10c2cf4d-ab26-4f2c-82d9-35e15cfa03bcCivil engineeringGeotechnical engineeringEnglishOxford University Research Archive - Valet2014Williams, EElizabeth S. WilliamsByrne, BBlakeborough, A<p>Pipelines used for the transportation of oil and gas products offshore are often buried beneath the seabed for protection from mechanical damage and for thermal insulation. During high temperature and high pressure operations, these pipelines are susceptible to resurfacing behaviour known as <em>upheaval buckling</em>, a structural response that is strongly influenced by the resistance of the surrounding soil. Despite much previous research on pipe uplift, the influence of the initial soil state – particularly in loose and liquefiable soil conditions – on the uplift resistance and corresponding buckling behaviour of the pipe is not well understood.</p> <p>This thesis presents research that examines the implications of these backfill conditions in the context of the global behaviour of the pipeline. The work consists of plane-strain monotonic uplift experiments focusing on density, rate, and stress level effects on the initial pipe-soil response. This is followed by numerical modelling of the global buckling behaviour using the experimental data as inputs. Finally, plane-strain cyclic experiments examine the possibility of progressive upward displacements over a number of cycles causing eventual upheaval buckling.</p> <p>A key finding from the uplift tests is that very loose backfill conditions may result in a localised flow-around failure mechanism, associated with lower peak resistance and a softer force-displacement response than with the sliding block mechanism that is typically assumed. This leads to lower peak buckling loads/temperatures than those predicted by current design guidelines. High quality data from both the monotonic and cyclic experiments was used to assess and suggest improvements to design guidance for these conditions.</p> |
| spellingShingle | Civil engineering Geotechnical engineering Williams, E Elizabeth S. Williams Upheaval buckling of offshore pipelines buried in loose and liquefiable soils |
| title | Upheaval buckling of offshore pipelines buried in loose and liquefiable soils |
| title_full | Upheaval buckling of offshore pipelines buried in loose and liquefiable soils |
| title_fullStr | Upheaval buckling of offshore pipelines buried in loose and liquefiable soils |
| title_full_unstemmed | Upheaval buckling of offshore pipelines buried in loose and liquefiable soils |
| title_short | Upheaval buckling of offshore pipelines buried in loose and liquefiable soils |
| title_sort | upheaval buckling of offshore pipelines buried in loose and liquefiable soils |
| topic | Civil engineering Geotechnical engineering |
| work_keys_str_mv | AT williamse upheavalbucklingofoffshorepipelinesburiedinlooseandliquefiablesoils AT elizabethswilliams upheavalbucklingofoffshorepipelinesburiedinlooseandliquefiablesoils |