基于气候学分析的寒区混凝土衬砌渠道冻害机理研究

Research on Frozen Damage Mechanism of Concrete Lining Canal Based on Climatology Analysis in Cold Regions

为了进一步分析寒区渠道衬砌冻害机理,从气候学角度,基于能量平衡原理,采用原型观测试验,研究了渠坡日平均日照时长和太阳辐射量的分布规律及其与渠基冻结特征的关系。结果表明,试验条件下,渠坡横断面各部位冻结期日平均日照时长、总辐射和净辐射呈不对称不均匀分布;渠道从渠底靠近阴坡坡脚3/4处至整个阴坡,日平均太阳净辐射为负值,渠基能量处于亏损状态;阴坡平均冻深为阳坡的1.5倍,阴坡平均冻胀量为阳坡的1.7倍。渠基能量收支的横向差异产生的横向不对称不均匀分布的温度场是渠道冻害的主要原因。

In order to further analyze frozen damage mechanism of lining Canal, daily average sunshine duration and solar radiation distribution laws of canal slopes and their relationships with canal foundation freeze characteristic were studied combined with prototype measurement from the perspective of climatology and the goal of energy budget. The results indicate that： solar radiation energy loss was the root cause of ground soil＇s freeze; the daily average sunshine duration, global and net solar radiation was lateral asymmetry and inhomogeneous in different parts of canal slope cross section; from three quarters of the canal bottom to the northern slope toe, the daily average net radiation was negative and canal foundation energy was under deficit; average frozen depth of northern slope was 1. 5 times deeper than that of southern slope, and average frost heave of northern slope was 1. 7 times greater than that of southern slope. The lateral asymmetry and inhomogeneous thermal field caused by lateral energy balance differences of canal foundation was the main reason of canal＇s frozen damage.