Development of centrifuge model test equipment for canals in seasonal frozen areas under cyclic action of wetting-drying and freeze-thaw

Seasonal frozen soil accounts for more than half of China's land area. The canals located in the seasonal frozen areas undergo a wetting-drying and freeze-thaw cycle with seasonal change and periodic change of water supply and suspension, thus causing damage to the canal structures. A centrifugal model test system which can simulate the cyclic action of wetting-drying and freeze-thaw under high gravity field is developed. The system consists of wetting-drying system, heat exchange system, sample model box, aboveground water cooler, data acquisition and control system. The wetting-drying system mainly includes the devices of rising and falling of water level and air drying. The heat exchange system includes the devices of semiconductor heat exchange and air internal circulation. The sample model box adopts double-layer heat insulation structure. The aboveground cooling water device can transfer the normal water of 30℃ to that of 3℃~5℃ for subsequent heat exchange system. The data acquisition and control system includes wetting-drying control, heat exchange control, data acquisition and analysis. The system can accurately control the model temperature between -40℃~30℃ and the moisture of soil in the drying-saturated state under a centrifugal force of 50g. It may provide a new important means for investigating the progressive deterioration process and mechanism of canals in seasonal frozen areas, and it can be applied to engineering researches in the fields of water conservancy and transportation in cold and arid areas.