Experimental Study On The Anti-Freezing Property Of Concrete Impervious Structure With Trapezoidal Channel And Curved Bottom

In northern area of China, the soil surface is frozen in winter,will be melted in spring,so the soil surface is experienced periodic frozen and melted. It can lead many water canals'impervious blocks which are located in the soil base to freeze-thaw damage in different positions, different forms and varying degrees. It's the seasonal frozen soil area in Shanxi Province, the freeze-thaw damage of channel lining is very serious. There are 50% of the main constructions, 40% of the canal system buildings and 32% of the canal bodies have been damaged because of the frozen and melted.This article was supported by the project of large and medium irrigation district project of Ministry of Water Resources"experimental study on the anti-freezing property of large concrete impervious structure with trapezoidal channel and curved bottom (Number 20081015)", based on the prototype in-situ observations of 14 species different concrete lining plate with trapezoidal channel and curved bottom, the frost heave characteristics of the canal was studied during the two freezing and thawing time, and this paper revealed the mechanism and the law of frost heaving of concrete lining plate with trapezoidal channel and curved bottom, analyzed the frost heave mechanism and the law of the major factors which influence the frost heaving of channel and the relationship among the factors comprehensive and systematically, compared anti-freezing effects cons with different forms of channel lining and advantages and disadvantages, proposed canal lining program optimization in test area climatic conditions, it established a mechanics model that use atmospheric temperature, channel section and the lining body size and so on as the physical parameters to calculate the frost damage of concrete impervious structure with trapezoidal channel and curved bottom. And on model-based ,Procedured for the preparation of the channels and reinforcement procedures for calculating Stress.The results show that:(1) In the winter, soil water content of channel base surface had large variations over time, water content in deep soil had stable variations relatively. Soil temperature was increased with soil depth. Soil temperature in the same depth was increased from channel roof to the channel bottom in the same time . Freezing index and soil water content, freezing index and soil temperature all have quadratic polynomial relationship.(2) The depth of frost lining plate with channel slope displacement sizes were not same. The displacement sizes near the top of the channel were the lest. The most displacement sizes were near the channel bottom. It had a visible vertical displacement sizes on the channel bottom. Frost crack damage resulting from sunny slope was less than shadey slope which have crack generally. The crack sites of the lining plate were focused on junctions of channel slope plate and arc angle or channel bottom and arc angle in the side of the shady lining plate. Frost heave displacement sizes with freezing index and soil temperature have cubic polynomial relationship. crack width and freezing index have quadratic polynomial relationship. crack width and soil temperature have exponential function relationship.(3) Canal concrete lining with square hole wire mesh or not had greater impact for the frost heave displacement sizes and crack width. Different lining type had different impact for soil temperature, soil water content and frost heave displacement sizes. With comparison, cast-in-situ reinforced concrete with geomembrane and 20cm slabs of vertical gap , cast-in-situ reinforced concrete with 8cm slabs and geomembrane and square hole wire mesh are considered the best linking program.(4) It is feasible that using conventional physical parameters program to calculate frost heave of concrete lining plate with trapezoidal channel and curved bottom. It can obtain a better forecasting result compared with engineering practice when using atmospheric temperature, channel slope angle and channel size and other parameters as variables.The topic takes the anti-frost heave property of channels'impervious blocks which are located in Yezhuang of the western trunk canal in Fenhe irrigation district as a research object. The project mainly studies the structure type of concrete lining plate with trapezoidal channel and curved bottom, the anti-frost-heaving measures. The reasults has practical significance for the key technologies which is badly needed to solve and the problems in the construction of large-scale irrigation area continuous matching project and water-saving reconstruction project. And it is have some scientific significance for the progress theory of hydraulic structure design of the anti-frost . But because of the complexity of the issue and the finite of the methods, many aspects have not yet been resolved or still at the level of qualitative research. it also remained to in-depth study in the further.