Study On Anti-frost And Frost Heave Of New Channel Insulation In Seasonal Frozen Ground Area

The problem of uneven distribution of water resources in northern China is extremely prominent.In response to the more glaring issue of water resources,the Ministry of Agriculture has proposed a strategic plan for the rational deployment of water-saving irrigation and water resources to regulate water resources.That is,through the canal system,the water in areas with relatively abundant water resources is transported to the northern areas that are severely deficient in water resources,thus mitigating water shortages in the northwest region to some extent.However,in the channels of seasonal frozen ground in northern China,the lining structure of the channel is vulnerable to damage due to the effects of winter freezing and spring flooding,resulting in a large amount of waste of water resources and land salt,affecting the normal operation of the channel management and increasing the Channel maintenance economic costs.At present,lining insulation boards are supported in the channels to weaken the frost heave of the channels.The use of insulation boards with excellent thermal insulation properties and small thermal conductivity can effectively improve the frost heave damage of the channel lining structure.However,in practice,insulation boards are used as the linking structure of the channels.There are still some channels of lining structure uplift phenomenon.The reason has not meant able to fully consider the effect of canal water leakage on thermal insulation panels and the influence of groundwater on thermal insulation panels.This article mainly studies the reasons for the declining insulation properties of the channel lining materials.At the same time,the lining insulation board is sometimes difficult to meet the requirements of anti-frost heaving of the channels because the groundwater is high and it is difficult to eliminate the canal sections.A new idea is proposed—precise heating,insulation,anti-seepage and anti-frost heaving.In the channel,certain thermal compensation is performed on the destructive surface of channels that are prone to frost heave damage,so that the canal soil of the channel does undergo frost heave deformation,thereby preventingthe lining structure from frost heave damage.Research directions and achievements include the following aspects:(1)To study the frost heave profile of the channel,elaborate the frost heaving mechanism theory of capillary theory,second frost heaving theory,freezing,and analyze the influence of various factors on the frost heaving damage of the channel.(2)Study the change of the effective thermal conductivity and moisture content of the insulation material under the two conditions of freezing and non-freezing.Studies have demonstrated that as the moisture content in the insulation board increases,the effective thermal conductivity of the insulation board increases and the insulation performance decreases.When moisture-containing insulation is frozen,the effective thermal conductivity of the insulation board is increased by 5 times compared to the effective thermal conductivity in the dry state.(3)Precisely heating the seepage and frost-swelling channels is to combine the related freezing and infiltration problems in the water-conveying irrigation channels,use the heating and thermal insulation plates to prevent frost heave,and use the self-impermeable layer of the heating and thermal insulation plates to prevent seepage.The temperature of the canal base was used to assess the temperature change,and a certain amount of heat was compensated for the canal soil,which prevented the freezing of the canal soil and the migration of water,thereby preventing frost heave damage.(4)Taking the main canal of Jingtai Power Phase II project as the research object,relying on the ANSYS software platform to simulate the accurate antifreeze and anti-seepage channels,the channel frost heave is modeled and analyzed in the stress field and the temperature field.Precisely heating and insulation anti-freezing and anti-seepage channels,when the channel is frost heaving,a certain thermal compensation is given to the channel to prevent the channel from frost heaving,and the maximum frost heave of the channel is reduced at the bottom of the channel and the position of the channel slope.The amount of frost heave at the bottom of the channel decreased by 46%,and the anti-frost heave effect was significant.