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Abstract Based on the theory of heat transfer，the heat analysis model for single pile foundation in permafrost region is established. Considering the pile exposed to air absorbing solar radiation and transferring heat through natural air convection，phase change in frozen soil and global warming，the change processes of ground temperature and bearing capacity of a single pile in representative humid permafrost region of Qinghai—Tibet plateau in next 40 years are analyzed with finite element method. The effects of pile length exposed to air and annual average temperature on ground temperature and bearing capacity of the pile are analyzed. Results show that solar radiation and global warming would rise the temperature at pile-soil interfaces and reduce the bearing capacity of pile. The longer the pile length exposed to air，the more the absorption of solar radiation which is obvious in winter with temperature rising and bearing capacity declining，while it is not obvious in summer. The initial annual average temperature significantly influences the bearing capacity of pile foundation. When the initial annual average temperature increases by 1 ℃，the bearing capacity of pile decreases by 800–1 000 kN in winter and 400–700 kN in summer.
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Received: 21 December 2012
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2014, Vol. 33 
