渠道混凝土防渗体下土体特性变化试验研究

渠道衬砌结构的冻胀破坏在寒冷地区普遍存在,对其使用效果和寿命造成了很大影响,为了解季节性冻土区渠道防渗体冻胀发生的原因,以梯形渠道弧形混凝土防渗体为例,从渠道衬砌结构的防渗体下土体温度变化及防渗体冻胀位移量变化特点入手,通过在灌区选取典型渠道进行原型原位观测试验,监测不同时间点不同影响因素下渠道不同位置土壤深度处地温及冻胀位移量变化,分析土体各特性的变化机理。结果表明,不同土层深度处土壤含水率的大小为未冻层>临界层>冻土层;不同土壤深度处的温度变化基本相同;10cm厚的保温板的保温效果优于20cm厚保温板的保温效果。研究成果为解决灌区渠道衬砌的冻害及渗漏问题以及未来大中型灌区渠道施工过程中采取有效的防冻胀措施提供了参考依据。

Experimental Study on Soil Characteristics Change under Channel Concrete Impervious Body

The frost heaving damage of channel lining structure is common in cold areas, and has great influence on its use effect and life. In order to understand the reasons that the concrete impervious body frost heaving happen in seasonal frozen channels, arc concrete impervious body of trapezoidal channel was taken for an example. From the aspects of the changes of soil temperature and frost heaving displacement characteristics of anti seepage body in channel lining structure, the prototype observation in situ tests were carried out in the selected typical channel in irrigation area. And then the changes of ground temperature and frost heaving displacement in depth soil at different locations were monitored under different influencing factors and times. The variation mechanism of soil body characteristics was analyzed. The results show that the descending sort of soil water content at different depth are non frozen soil layer, critical layer, frozen soil layer. The change of temperature in different depth soil is basically no difference. The effect of warming plate insulation in 10 cm thickness is better than that of 20 cm thickness. The research provides reference basis for solving the problems of freezing injury and leakage of irrigation channel lining, and taking effective measures to prevent frost heaving in the future construction of large and medium irrigation channels.