Title Development of freezing-thawing processes of foundation soils surrounding the China-Russia crude oil pipeline in the permafrost areas under a warming climate
Author Li Guoyu; Sheng Yu; Jin Huijun; Ma Wei; Qi Jilin; Wen Zhi; Zhang Bo; Mu Yanhu; Bi Guiquan
Author Affil Li Guoyu, Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, Lanzhou, China
Source China-Russia crude oil pipeline in permafrost regions in northeastern China, edited by Jin Huijun, G. Gay and M.C. Brewer. Cold Regions Science and Technology, 64(3), p.226-234, . Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0165-232X
Publication Date Dec. 2010
Notes In English. Based on Publisher- supplied data GeoRef Acc. No: 309512
Index Terms climatic change; construction; design; foundations; freezing; frost heave; global change; global warming; permafrost; pipelines; pipeline freezing; soil mechanics; taliks; thawing; thaw depth; China; Asia; China-Russian oil pipeline; climate change; cyclic processes; depth; Far East; freeze- thaw cycles; frost heaving; Mo'he Station; northeastern China; numerical models
Abstract The proposed China-Russia Crude Oil Pipeline (CRCOP) will be subjected to strong frost heave and thaw settlement of the surrounding soil as it traverses permafrost and seasonally frozen ground areas in Northeastern China. The freezing-thawing processes, the development of the maximum frozen cylinder in taliks and thawed cylinder in permafrost areas, and the variations in the maximum freezing depths under the pipeline in taliks and thawing depths in different permafrost regions near Mo'he station, the first pumping station in China, were studied in detail using numerical methods in this paper. The inlet oil temperature at Mo'he station was assumed to vary from 10 to -6C in a sine wave form during the preliminary design phase. Research results showed that the freezing-thawing processes of soils surrounding the buried pipeline had distinct differences from those in the undisturbed ground profile in permafrost areas. In summer, there was downward thawing from the ground surface and upward and downward thawing from the pipeline's surface once the temperature of the oil rose above 0C. In winter, downward freezing began from the ground surface but upward and downward cooling of the cylinder around the pipeline didn't begin until the temperature of the oil dropped below 0C. However, in the undisturbed ground profile, downward thawing from the ground surface occurred in summer and downward freezing from the ground surface and upward freezing from the permafrost table occurred in winter. The maximum thawing depths and thawed cylinder around the pipeline in warm permafrost enlarged with elapsing time and decreasing water content of the soils. In taliks, the maximum freezing depths and frozen cylinder around the pipeline kept shrinking with elapsing time and increasing water content of the soils. The freezing-thawing processes and development of the thawed and frozen cylinders around the pipeline were muted by any insulation layer surrounding the pipeline. Insulation had better thermal moderating on the heat exchange between the pipeline and the surrounding soils during the early operating period. But its role slowly weakened after a long-term operating. Research results will provide the basis for assessment and forecasting of engineering geological conditions, analysis of mechanical stability of the pipeline, foundation design, and pipeline construction and maintenance.
URL http://hdl.handle.net/10.1016/j.coldregions.2009.08.006
Publication Type journal article
Record ID 65006595