青藏高原地区混凝土冻融环境量化方法  

Quantitative method for freezing-thawing environment of concrete in Qinghai-Tibet plateau

作　　者：李雪峰[1] 付智[1] 王华牢[1] 

机构地区：[1]交通运输部公路科学研究院,北京100088

出　　处：《农业工程学报》2018年第2期169-175,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(51308846)

摘　　要：对青藏高原地区混凝土冻融环境进行合理量化是高原抗冻混凝土设计所面临的首要问题。该文通过对处于同一冻融环境作用等级下的平原与高原地区大气及地表温度特征进行比较,发现相较于平原地区,高原地区因太阳辐射强度大,具有年正负温交替次数更多、温度日较差更大且日最低温更低的环境温度特征。通过将地表温度近似代替混凝土结构物表面温度,结合青藏高原1971-2003年20个地区的典型气象年数据,建立了与最冷月平均气温及年太阳辐照量相关的青藏高原地区混凝土年均冻融循环次数确定方法。利用该方法对青藏高原主要地区混凝土年均冻融循环次数进行估算,结果表明,青藏高原地区混凝土年均冻融循环次数主要集中在150次以上,部分地区甚至大于200次,因此,高原地区应加强对混凝土进行抗冻耐久性设计。最后,该文给出青藏高原地区混凝土结构物抗冻设计等级推荐值。该研究可为青藏高原地区混凝土抗冻耐久性设计提供参考。Owing to the higher annual solar radiation and the thinner atmosphere compared to the plain area,plus and minus temperature appear alternately day and night in the Qinghai-Tibet Plateau.Therefore,concrete cast in the Qinghai-Tibet Plateau should have an excellent anti-frost durability.However,current proposed approaches to quantitatively evaluate the number of freeze-thaw cycles of concrete per year are mainly based on the freezing-thawing environment of the plain area.In this paper,firstly in order to compare the freezing-thawing environment difference between the Qinghai-Tibet Plateau and plains,according to the determining criterion of freezing-thawing environment listed in Code for durability of concrete structure,3 groups of cities from different areas located in the Qinghai-Tibet Plateau and the plains respectively were selected,which had the same freezing-thawing environmental grade.In the meanwhile,because the freeze-thaw damage of concrete usually takes place on the surface and physical thermal parameters between concrete and soil are nearly equal to each other,the land-surface temperature is in good agreement with the concrete-surface temperature.Then the land-surface temperature was utilized to replace the concrete-surface temperature,and the air temperature and land-surface temperature of the 3 groups of cities were compared.The results demonstrate that in the Qinghai-Tibet Plateau the number of freeze-thaw cycles of concrete per year is more,the diurnal range of temperature is much larger and the lowest temperature is much lower than those of the plains.Due to without considering the freezing-thawing environmental difference between the Qinghai-Tibet Plateau and plains mentioned above,it was found that current calculating methods could underestimate the number of freeze-thaw cycles of concrete per year and are insufficient for durability design for concrete in Qinghai-Tibet Plateau.Based on the above analysis,the quantitative method for the freezing-thawing environment of concrete in Qinghai-Tibet Pl

关 键 词：混凝土 温度 太阳辐射 青藏高原 冻融环境 最冷月平均气温 抗冻设计等级 

分 类 号：TU528[建筑科学—建筑技术科学]