渠道混凝土衬砌与基土界面冻胀温度特性研究

Characteristics of frost heave temperature of concrete lining and foundation

通过室内冻结试验,研究渠道混凝土衬砌与渠床基土两材料相互接触界面的温度变化,分析试验结果可知界面温度时程变化可划分为3个阶段:急速阶段、缓慢阶段和平稳阶段。结合材料力学、冻土力学等理论,利用温度场、温度梯度和温度应力计算公式得出界面温度应力变化特性。在冷端温度降低过程初期,混凝土内部温度变化较基土更为敏感;界面温度达-12℃时,界面温度应力的增速由快变慢且存在转折点,该转折点使温度应力对界面的破坏速率减慢,温度应力大于0.4MPa时会对界面有破坏效应;界面温度达-15℃时,应力达到最大值。室内冻结试验与灌区渠道冻胀变化趋势基本一致,具有实践应用价值。

The interface temperature changes between channel concrete lining and channel bed soil two material interaction can be evaluated by an indoor freezing test and the analysis results show that the interface temperature variation can be divided into three stages：rapid stage,slow and steady stage.Combining the theory of material mechanics and frozen soil mechanics and using the computational formula of temperature field,temperature gradient and thermal stress,the variation characteristic of interface temperature stress can be obtained.In the early stage of cold end temperature reduction,the internal temperature of concrete was more sensitive than that of base soil.Meanwhile,when interface temperature reached to-12℃,the interface temperature stress grew from fast to slow and there was a turning point,which slowed the rate of temperature stress on the interface.When temperature stress exceeded 0.4 MPa,it would have a damaging effect on the interface.In addition,when interface temperature reached to-15℃,the stress reached maximum value.The indoor freezing test was basically consistent with the trend of frost heave changes of channels in pouring area,and it was of practical application value.