Study On The Reasonable Thickness Of Anti-seepage Channel And Thermal Insulation And Anti-freezing Measures Of Thermal Insulation Layer Which Is Made Of Concrete In Cold Region

At present, the seepage control of canal is the commonly used measure in water-saving projects inChina and have achieved good results, but in northern area of our country, the canal engineering oftensuffers from cold damage, because the majority of seepage control of canal use concrete slab, whichbelongs to the rigid material and whose tensile capacity is relatively small, so when suffering frost, it iseasy to damage. The frost prevention channel engineering in most of the northern irrigation district is now aproblem that should be solved quickly in the construction of water conservancy project. Benzene boardinsulation anti-freezing measure is one that has developed in recent years. However, the laying thickness ofconcrete is still not clear, which is very easy to cause the circulation pattern of design–Construction-redesign.This will cause a lot of unnecessary waste. Through theory analysis and computersimulation, we find the law of benzene board laying thickness of benzene board which will have certainguiding function for future design.The main work and achievements are as follows:(1) It summarizes the research status of frost heaving in three aspects, which are the main researchprogress situation of cold damage, the frost heaving prevention measures and the frost heaving progress athome or abroad.(2) Through the analysis of the capillary theory, second, segregation frost theory frozen heavemechanism theory, analyzing on the main factors of roost heave soil, moisture, temperature, load, soildensity and channel to channel etc separetely, and according to different structural forms such astrapezoidal, trapezoidal, U shape, we have a further analysis of the characteristics of damage of concretelining channel.(3) based on the finite element theory, models are set up with the real examples of Gansu Jing totaldry trapezoid and arc base trapezoidal channel and the North Channel of Baoji Gorge Irrigation District.Through the finite element software ANSYS, the temperature field of frost heaving stress field anddisplacement field was simulated, and the simulation results and the measured results were compared. It ison this basis that verifying the obtained thermal insulation board is provided with different thickness of thefrost effect. Temperature distribution of the slope of Yin and Yang has obvious differences. Temperaturegradient slope is higher than that of the sunny slope and the slope of the frozen depth distribution andtemperature distribution is basically the same, so the slope and ditch bottom frost depth was higher thanthat of the sunny slope; channel slope deformation value is the largest, and the slope and ditch bottom issmall, the canal bottom tilts inside the channel obviously. The channel had a whole lift and the orientationof small deflection in sunny slope under the action of frost heave.(4) By the analysis and comparison of no insulation measures and laying of polystyrene insulationlining two simulation, it can be found that the benzene board has small coefficient of thermal conductivityand can effectively prevent or slow negative temperature entering the channel soil, and improve the soil temperature, thus reducing the channel lining failure. Seen from the stress and deformation, the amount offrost heaving is reduced greatly, and the easiest position to produce cracks area in the slope stress value isalso significantly reduced to a permissible value. According to the analysis of the different thickness ofbenzene board insulation model simulation, it can be obtained the reasonable thickness of the canal sectionof insulation benzene plate on the sunny slope is6cm, and shady slope ditch bottom8cm.