Finite Element Analysis Of Frost Heaving Damage Of Canal With Concrete Lining And Study On The Application Of Anti-frost Heaving Insulation Materials

Nowadays, water shortage has become a "bottleneck" which restrict the sustainabledevelopment of Chinese economy and society, construction of water-saving society isimperative. Because agricultural water is the major part of water consumption, its water useefficiency is not high and the phenomenon of waste is serious, it is top priority to implementwater-saving agriculture. Channel conveyance technology is one of the main water-savingtechnologies in the research and application of water-saving agriculture in China. Preventionof channel frost heaving damage is the key problem of channel water saving technologyresearch. However, the area of seasonal frozen soil distributes about54%of land in China.A large number of channels are destroyed under the action of freezing and thawing, and itnot only affects the normal operation of the project, increases the difficulty of theengineering management maintenance and cost, but also affects the effect of seepageprevention. Therefore, in the process of developing water-saving agriculture, to improve theefficiency of the water saving by the technology of preventing channel seepage, furtherresearching on channel cold injury problems must be made.In this paper, combining with the national "863" plan project <product development andindustrialization development about new materials and new equipment of channelanti-seepage and anti-freeze bulge and water monitoring>, based on consulting a largenumber of related literature at home and abroad, research on the frost heave damage ofconcrete lining channel and the application of thermal insulation material of channelanti-freeze expansion. The research results can provide scientific evidence on channelsanti-freeze expansion design, insulation materials and the selection of its thickness. Themain research results of this paper includes four parts:1、Frost heaving damage mechanism of channel concrete lining, the factors ofinfluencing frost heaving damage and the frost heaving damage characteristics are analyzed.On this basis, the reasonable technologies of anti-seepage and anti-freeze expansionmeasures are put forward, one is to improve the temperature field and humidity field offoundation soil, the other is to select the reasonable cross section form and lining structure. 2、Based on finite element method, take the triangle subdivision unit for example,established the mathematical model which is used for calculating the temperature field,displacement field and stress field in the process of the frost heaving damage of concretelining channel, it provides the theoretical basis for analyzing the frost heaving damage ofconcrete lining channel based on finite element method.3、Regard the foundation soil as the isotropic linear elastic material, and the frozen soiland concrete lining board as a whole, taking the arc bottom trapezoid channel of the maincanal in Jinghui of Gansu Province as the object of study, analysis of heat-structuralcoupling, studied the distribution law of the temperature field, displacement field and stressfield. The results of temperature field conform to the temperature distribution law of thechannel slope and bottom, and is consistent with the frozen soil depth. The results ofdisplacement field is consistent with frost heave deformation condition, simulation resultsmeet the accuracy requirement. The results of stress field show that the parts in the channelwhich are prone to frost heave damage produced large tensile stress.4、Through contrasting and analysing three insulation materials which are hydrophobicpearlite, polystyrene and extruded polystyrene, extruded polystyrene insulation type slabshas the best effects for channel heat preservation under the same thickness. On this basis,analyzed the temperature field distribution and frost heave displacement changes when thearc bottom trapezoidal channel paved different thickness of XPS, according to this, chosethe reasonable thickness of XPS for the channel, the reasonable thickness was4cm.Consequently, provides technical support for selecting the insulation board thickness andconstruction.