Frost Heaving Monitoring Research On Small U-shaped Lining Canal Of Ningxia Yellow River Irrigation Area

In the irrigation area of Ningxia, Small U-shaped canal is the main form of agriculture irri gation. However, in the influence of freeze-thaw cycle, the frost heaving damage of canal concr ete lining hinders the irrigation area of farmland water conservancy facilities construction and a gricultural sustainable development.Based on researching a large number of domestic and foreign literatures, discussing the do mestic and foreign research status of frost-resistant of small canal lining, summarizing the new technology and materials of frost-resistant of small canal lining, studying the main factor influe ncing the canals of frost heave damage and frost heaving damage characteristic and mechanism of lining canals. Because the study of frost heaving of small U-shaped canal has not researche d greatly yet, this thesis selects two typical canals in the irrigation area, decorating the given e xperiment, observing the damage of canal lining board, monitoring the frost heaving force, getti ng basic information and data, understanding the frost heaving damage properties, identifying th e most weak part of the canal, looking forward to revealing the small U-shaped concrete lining the inner rules of frost heaving damage, providing technical support of formulating perfect con struction regulations of small U-shaped canal concrete lining, insuring it works well.The specific research results are as follows:(1) In the observation, the frost heaving damage of two arc-plates is the most seriously, d amage types includes:cracks, displacement, fracture, slump, uplift overhead, overall rising, comp rehensive damage. Three arc-plates includes:cracks, displacement, fracture. Integral canal includ e cracks only.(2) Temperature and depth were positively correlated ground temperature, for integral canal, the bottom> sunny side> shady side, external of canal slope lower than internal of canal slope, for two arc-plates and three arc-plates, the bottom> downside of sunny side> downside of shady side> upside of sunny side> upside of shady side. Between geothermal and duration of freezing-thawing period, has a quadratic function relationship, ground temperature is the result of accumulative temperature over a period of time.(3) With the increase of depth, soil moisture content also increases, Before and after freezing-thawing, moisture content is almost the same. In the process of freeze, moisture content reduces. The moisture content of the bottom is highest. Temperature is negatively correlated with frost line.(4) Comparing with other place, the bottom, slope toe is the most fragile place for frost heaving damage, for integral canal and three arc-plate, downside of canal is more severe than upside.