水库坝前水温统计分析

Statistical Analyses of Reservoir Water Temperature near Upstream Dam Face

水库坝前水温是确定混凝土坝体温度场的一个最重要的边界条件，由于受坝址区的气候条件、水库的特征（库容、水深等）、水库运行方式等因素影响，水库坝前水温的分布非常复杂．本文以国内外26个已建工程的坝址气温和坝前水温的多年实测资料为基础，建立了水库水温统计分析的数学模型．坝前水温随时间的变化用余弦函数表示，水温沿水深的分布用指数曲线表示．根据对各工程实测资料的统计分析结果，提出了一套简明实用的计算水库坝前水温的公式．经验证本文公式比现行规范中水库水温的计算公式具有更高的精度．

The reservoir water temperature near upstream dam face is the most important temperature boundary used in determining the temperature field of concrete dam. Affected by the atmospheric condition near dam site, the characteristics of reservoir (reservoir volume, water depth, etc), and the reservoir's operation mode, the reservoir water temperature distribution is rather complicated. According to the measured ambient air temperatures and reservoir water tem-peratures of more than 20 projects, the mathematical model for statistical analysis of reservoir water temperature is established. The reservoir water temperature change along with time is ex-pressed as a cosine function of time. A exponential curve is adopted to describe the distribution of reservoir water temperature. A set of formula for calculating the reservoir water temperature near upstream dam surface, which are simple in expressing and convenient in use, is suggested according to the statistical analysis results of the measured data. It is proven that the formula suggested in this paper is more accurate in determining the reservoir water temperature near up-stream surface than the one currently used.