Field Investigation of Soil Heave by a Large Diameter Chilled Gas Pipeline Experiment, Fairbanks, Alaska

• Published in: Journal of cold regions engineering Vol. 18; no. 1; pp. 2 - 34
• Main Authors: Huang, Scott L, Bray, Matthew T, Akagawa, Satoshi, Fukuda, Masami
• Format: Journal Article
• Language: English
• Published: Reston, VA American Society of Civil Engineers 01.03.2004
• Subjects: Applied sciences; Buildings. Public works; Energy; Exact sciences and technology; Fuels; Gas industry; Gas transmission and distribution. Ships. Pipelines. Distribution networks. Compressors stations; Geotechnics; Soil investigations. Testing; TECHNICAL PAPERS; Alaska; United States; North America; America; Differential settlement; Cold regions; Gas pipeline; Instruments; CE Database subject headings: Field investigations; Property of soil; Temperature effect; Permafrost; Experimental study; Field experiment; Soil heave; Hydrology; Alaska; Gas pipelines; Frost effect; Cold climate; Thermal analysis; Monitoring; Ground water
• ISSN: 0887-381X; 1943-5495
• DOI: 10.1061/(ASCE)0887-381X(2004)18:1(2)

A large scale 105-m-long, 0.9-m-diam chilled pipeline experiment was conducted to assess the response of a production pipeline that transits between unfrozen (seasonally frozen) and permafrost soils in discontinuous permafrost regions. Thermal and heave characteristics of the experiment for a three-year monitoring period are reported. In response to the chilled pipeline, the progressive cooling patterns within the permafrost and unfrozen soils were different, resulting in the development of a thermal boundary at the transition zone between the two thermally different soils. The absolute maximum movement of pipeline was 0.197 m near the thermal boundary, resulting in a differential heave of 0.148 m. Three distinct heave phases were identified within the unfrozen soil. Phase 1 of the first 200 days related to penetration and heave above the groundwater table and was characterized by heave rates between 0.211 and 0.237 mm/day. Phase 2 resulted in increased ice segregation due to interaction of the freez-ing front with the groundwater table. This phase lasted from approximately day200 to day 500 and corresponded to a heave rate from 0.206 to 0.313 mm/day. Phase 3 was characterized by a further decrease in the heave rate to about 0.081 mm/day and lasted from approximately day 500 to day 1,056.