| China is a traditional agricultural country.There is a serious waste of water for agricultural irrigation.Channel lining is the most important measure to improve the rate of water for agricultural irrigation.In seasonal frozen soil areas such as northern China,the frost heave damage of canal engineering can not be ignored,which seriously wastes agricultural water.Therefore,it is of great practical significance to study the damage of canal lining structure caused by the frost heave of canal foundation soil in Shenyang area.In order to study the channel frost heaving problem in the northeast seasonal frozen area,extensive investigation and research on the frost heave of the irrigation channel in Shenyang area was carried out,and the relevant literatures on frost heave research at home and abroad were combined to determine the main factors affecting the frost heaving of the channel foundation.The soil,the low temperature required for frost heaving,and sufficient water supply.The trench soil in Shenyang area was selected as the test object,and a test device with a cylindrical soil model with a diameter of 10 cm and a height of 15 cm with bottom and surrounding insulation and lateral restraint was designed and manufactured to meet the one-way freezing condition from top to bottom.The whole test device is composed of a sample cylinder,a low temperature freeze-thaw test machine,a water supply system,a data acquisition system,a frost heave measuring instrument and a temperature measuring instrument;Basic experiments were carried out and a series of indoor frost heave tests were designed.The sample has a compaction of 0.9,a moisture content of 16%,22%,28%,34%,and the cooling rates are 4 ° C / h,6 ℃ /h,8 ℃ /h until the temperature drops to-25 ° C and Control test at a constant temperature of-25 ° C.The variation law of different soil temperature of the frost heave of the canal soil in Shenyang area was determined under the two conditions of open system with groundwater recharge and closed system without groundwater recharge.The results show:By analyzing the displacement field of the sample during freezing process,the maximum frost heave is 6.1 mm and the minimum frost heave is 0.93 mm under open system conditions.The maximum frost heave is 4.1 mm and the minimum frost heave is 0 mm in the closed system.Therefore,under the same freezing conditions,the frost heave of the specimen under the open system condition is larger than that under the closed system condition.The frost heave of the 34% moisture content sample is greater than the water content of 16%,22% and 26%.The higher the water content,the greater the frost heave ratio.By regression analysis,the regression equation with good fitting results is obtained.Within the given range,the maximum frost heave ratio of the soil under the closed system is 3.31%,and the maximum frost heave ratio of the soil under the open system is 4.35%.The frost heave rate can be used to obtain the frost heave of the foundation soil of the canal in Shenyang,and the appropriate thickness of the canal insulation layer in Shenyang is optimized.In the absence of groundwater recharge and groundwater recharge,the thickness of the benzene plate required for the trapezoidal section is 10.17 cm and 10.78cm;the thickness of the benzene plate required for the trapezoidal section at the bottom of the arc is 6.11 cm and 7.77cm;the benzene required for the large U-shaped section The plate thickness is 7.74 cm and 8.69 cm.From the perspective of safety performance,engineering cost and construction technology,the trapezoidal section at the bottom of the arc is the optimal section form. |
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