摘要
作为主动保护冻土的典型措施之一的路堤边坡遮阳板护坡措施，对于减少太阳直接辐射到达地表和降低路堤内部温度起到至关重要的作用，阻隔太阳的辐射，减少进入路堤净辐射量和进入地表的热流，降低路堤土体温度．现场试验结果表明：进入天然路堤边坡表面平均净辐射量为300～350W·m^-2，而遮阳板下路堤边坡表面的平均净辐射量为30～45W·m^-2，其减少程度平均达到天然总净辐射量的80％～90％以上；在遮阳板护坡措施保护下进入路堤土体热流减少50％～75％；遮阳板下地表温度低于天然边坡6～8℃．所有监测结果表明，遮阳板护坡措施能够快速有效地减少进入路堤表面的净辐射量和热流值，从而达到降低路堤表面以及土体内部温度，改善路堤土体温度场，在全球变暖的背景下有效延缓了路堤土体温度的抬升速率，保证了路堤稳定安全，确保寒区道路工程的运营畅通．
Because of the higher elevation and bet- ter atmosphere transparency, the Tibetan Plateau has stronger radiation than other regions, which let the daily variation of ground surface temperature more obvious. The shading board measure is one of the active protecting permafrost measures, which has been adopted, widely along the QinghaiTibet railway and highway. The main contribution of the shading board measure is to cut off the sun radiation directly come to ground surface, and to reduce the net radiation and heat flow entering into the embankment, which ensure the embankment temperature lower, the roadbed permafrost sta- tionary and embankment safety. The field test shows that the mean net radiation into the em- bankment is 300-350 W · m-2, but it is 30-45 W ·m-2 under the shading board, 80%~90% de- creasing of the nature net radiation. The shading board make the heat flow entering into embankment reduce 50%-75%. At the same time, the shaded ground surface temperature is 6-8 ℃ lower than original embankment. All the test results show that the shading board measure can reduce the net radiation and heat flow into the embankment rapidly and effectively, then, it is possibly to lower the embankment height and the temperature inside the embankment, to delay the soil temperature rising effectively under the globe warm back- ground, to ensure the embankment stable and safety, and to guarantee the roads unblocked in cold and permafrost regions.
出处
《冰川冻土》
CSCD
北大核心
2011年第4期778-783,共6页
Journal of Glaciology and Geocryology
基金
中国科学院冻土工程国家重点实验室自主基金项目(SKLFSE-ZY-03)
中国科学院西部行动计划(二期)项目(KZCX2-XB2-10)
国家自然科学基金创新群体项目(40821001)
国家自然科学基金项目(40801022
40801024
40801026
41023003)资助
关键词
寒区
路堤
遮阳措施
净辐射
热流
cold regions
embankment
shading board measure （awning）
net radiation
heat flow
