摘要
通过对混凝土大坝冻胀变形机制的分析,本文对冻胀变形统计分析模型的冰冻因子的构成进行了改进,采用了定周期、定初始角的周期函数因子和气温滞后作用因子等两类因子构成冻胀变形的因子集。对丰满大坝坝顶廊道真空激光准直典型位移测值的模型分析表明,改进的统计模型具有以下特点:(1)拟合效果优于或接近传统模型;(2)模型的物理意义更为明确合理,可以较好地解释历年"双峰"现象。温度分量仅反映传统意义上的简谐温度场变化所产生的结构变形,温度分量的变幅及相位可以正常地得到反映;(3)可以对季节性冻胀的影响进行直接分析,对变化量值进行一定的估计;(4)与传统模型相比,冻胀模型回归结果中的水位分量、时效分量相差不大。从资料分析的角度来看,增加"冻胀因子"并未使问题复杂化。总体来看,本文所建立模型方法是有效的。对于冻胀问题较为严重的混凝土大坝如丰满,有必要采用考虑冻胀因子的模型进行分析,以了解及评价冻胀对变形性态的影响,对大坝老化评估也是很有意义的。
In this paper, freezing factors in the statistics model of frost heaving deformation were improved through the mechanism analysis of frost heaving deformation of concrete dams. The factors group consists of two kinds of factors, they are period function factors of given period and given initial angle and air temperature hysteresis effect factors. The improved models were used in the analysis of crest displacement of Fengman dam. It showed that new models have four advantages as following： a） they are better than traditional ones in terms of fit goodness; b） they have clearer physical meaning so that they can be used to explain ＂two-peak＂ phenomenon in the past years; c） they can be used to directly analyze the effect of the seasonal frost heaving and to estimate the varying scope; d） the reservoir-level component or the time component is close to that in traditional model. Totally, the new model is effective. This method can be used for analysis of frost heaving deformation of concrete dam like Fengman dam, as well as for aging evaluation.
出处
《大坝与安全》
2007年第4期28-32,共5页
Dam & Safety
关键词
混凝土坝
冻胀变形
统计模型
冰冻因子
老化评估
concrete dams
frost heaving deformation
statistics model
freezing factors
aging evaluation
