Observation and analysis on the characteristics of strain induced by frost heave for a full-scale buried, chilled gas pipeline

• Main Author: Yang, Kun
• Other Authors: Huang, Scott, Chen, Gang, Darrow, Margaret
• Format: Thesis
• Language: English
• Published: 2013
• Subjects: Fairbanks; permafrost; Alaska
• Online Access: http://hdl.handle.net/11122/4457

Thesis (M.S.) University of Alaska Fairbanks, 2013 This thesis examines the strain characteristics of a large-scale, buried chilled gas pipeline in the discontinuous permafrost region. A full-scale chilled pipeline gas experiment was conducted in Fairbanks, Alaska. The test pipeline had a length of 105 m and a diameter of 0.9 m. One-third of the pipeline was located in permafrost and the rest was in non-permafrost. The monitoring data were collected from December 1999 to January 2005 including both freezing and thawing phases. In the transition zone between frozen and unfrozen soil, the foundation experienced a vertical movement caused by differential frost heave. The test results indicated that the bending action was the main factor for the pipeline for the circumferential and longitudinal strain distribution of the pipeline. Moreover, linear relationships were developed between frost heave and the longitudinal strain at the top and the bottom (i.e., 0� and 180�) of the pipe. The developed equations can be used to predict the strain of the pipe caused by differential frost heave for future tests with similar site conditions. Chapter 1. Introduction -- 1.1. Overview -- 1.2. Objective of the research -- 1.3. Literature review -- 1.3.1. Frost heave mechanism -- 1.3.2. Soil-pipeline interaction -- 1.3.3. Prior buried chilled pipeline experiments -- Chapter 2. Test facility of a field experiment -- 2.1. General layout of the test facility -- 2.2. Monitoring parameters and instrumentation -- 2.2.1. Air and ground temperatures -- 2.2.2. Pipe strain -- 2.2.3. Pipe movement -- Chapter 3. Frost heave data analysis -- 3.1. Heave rod data -- 3.2. Heave gauge data -- Chapter 4. Analysis of frost heave induced strain -- 4.1. Data processing -- 4.2. Strain development over time -- 4.2.1. Circumferential strain -- 4.2.2. Longitudinal strain -- 4.3. Strain distribution -- 4.3.1. Strain distribution on cross sections -- 4.3.2. Distribution of strain in longitudinal direction -- Chapter 5. Correlation between strain and frost ...