青藏高原多年冻土区单桩承载力的长期稳定性  

Long-term stability of bearing capacity of single pile in permafrost area on Qinghai-Tibetan Plateau

作　　者：蒋代军[1] 郭春香[1] 

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070

出　　处：《长安大学学报（自然科学版）》2016年第2期59-65,共7页Journal of Chang’an University(Natural Science Edition)

基　　金：国家自然科学基金项目(51268033);国家自然科学基金重点项目(51236003);长江学者和创新团队发展计划项目(IRT1139);兰州交通大学校青年基金项目(2013030)

摘　　要：为了应对在青藏铁路建设桩基础设计中由于未来气候变暖可能导致的冻土融化及承载力下降问题,以传热学理论为基础,建立了冻土地基单桩地温场的热分析模型,采用有限单元法考虑裸露桩基表面吸收太阳辐射的同时,在大气自然对流换热、冻土相变、气候变暖等条件下,计算分析了典型湿润性永久冻土区在未来30年单桩地基桩土体系的温度变化及其长期承载力的变化趋势。研究结果表明：地表以下3~20m在2010~2040年30年间,天然地温与桩土体系温度随着时间均有升高,单桩承载力在未来时间内有降低趋势;2040年夏季桩基承载力较2010年同期下降了41.5%,冬季桩基承载力较2010年同期下降了28.6%;在未来的寒区桩基础设计中应充分考虑这一＂动态因素＂,对于目前已建成桩基础,提出合理有效的提高桩基承载力的措施是解决这一问题的关键。In order to solve the possible problems of decline bearing capacity and thawing of frozen soil resulting from future global warming in the design of pile foundation in Qinghai-Tibet Railway,thermal analysis model of ground temperature field for a single pile in permafrost was established based on the theory of heat conduction.Considering the condition that pile exposed in air absorbed solar radiation and transferred heat with natural air through convection,phasechange and global warming,ground temperature and long-term bearing capacity changes of a single pile in representative humid permafrost area in future 30 years were calculated and analyzed by using finite element method.The results show that in the coming 30 years,the natural geotherm and the temperature of the pile-soil system 3to 20 m under the surface of the earth become higher as time goes by;the bearing capacity of single pile has the decline tendency infuture.In 2040 summer,the bearing capacity will drop by 41.5%compared with the same period in 2010;in winter the bearing capacity will drop by 28.6% compared with the same period in2010.The＂dynamic factors＂should be taken into account in basic pile design work in cold region in future.For the existing piles,reasonable and effective measures should be taken to improve the piles bearing capacity,which is key in solving the problems.

关 键 词：岩土工程 桩基础 太阳辐射 气候变暖 承载力 长期稳定性 

分 类 号：U416.168[交通运输工程—道路与铁道工程]