Study On The Lining Form Of High Groundwater Level Irrigation Canal In Seasonal Cold Area

The frost heave damage of high groundwater channels in seasonal cold areas in my country is very serious.In order to improve the stability of the lining structure,the permeable solid lining structure design of concrete lining boards and gabion gabions is often used.In the non-irrigation period,this structure can allow groundwater to seep back to slow down the frost heave damage of the lining and prolong the service life of the channel.However,the water delivery capacity under the same section size is far lower than that of a full-section concrete lining channel.In order to optimize the lining form to ensure that the channel is not affected by winter frost heave damage and can meet the water-saving benefits,this paper carried out a numerical simulation experiment on the permeable solid lining channel from the channel seepage and frost heave,and used the model test to simulate the numerical simulation.The structure was verified,and finally several lining forms were compared and selected based on the economic characteristics of channel lining.The main conclusions of this article are as follows:(1)The seepage flow increases linearly with the increase of the canal water level,and decreases linearly with the increase of the groundwater level;when the width of the channel solid lining is fixed,the seepage flow per unit head of channels of different sizes is basically the same;the seepage flow increases with the width of the solid seepage Larger and larger,there is a critical permeable solid lining width,about 0.1m under the condition of sandy soil;the seepage flow is the smallest when the permeable solid is arranged in the middle of the canal bottom,and the seepage flow is the largest when the permeable solid is arranged at the bottom of the canal slope;the larger the permeability coefficient of the permeable solid material is,The greater the leakage,the different curvatures of the solid width-leakage curve of different materials,the smaller the permeability coefficient,the smoother the solid width-leakage curve.Through sensitivity analysis,it is known that the difference in water head has the greatest impact on channel seepage,and the channel size has the smallest impact on channel seepage.An indoor model test box was used to conduct a canal seepage test to verify the reliability of the numerical simulation results.(2)The frost heave of trapezoidal channels is unevenly distributed.The deformation of the middle and lower part of the lining slope is large,and the deformation of the lining bottom plate is large in the middle and small at the two ends.The frost heave of the channel shows that the lining slab rises as a whole;the amount of frost heave and the frost heave force It is not proportional.The frost heave force is not necessarily the largest at the place where the amount of frost heave is large.There is obvious stress concentration at the top of the Yin and Yang slopes;when the permeable solid is arranged at the bottom of the canal slope,it is most beneficial to reduce frost heave.(3)When the permeable solids are arranged in the middle of the bottom of the canal,the construction cost per canal length is the lowest.Combining the three indicators of water saving,degree of frost heave reduction and project cost,it is believed that the channel with high groundwater level in seasonal cold area is more suitable to adopt the form of permeable solid lining at the edge.