Research On Temperature Characteristics Of Ventilated Embankment With Porous Tubes Based On Local Non-thermal Equilibrium Theory

The ventilated embankment with porous ventilated tubes inside is a bran-new engineering measure, whose nonlinear temperature characteristic was studied in this paper.1. Refrigeration mechanism of ventilated embankment with porous tubes inside was presented, which is that air cool embankment by heat convection inside embankment medium under conditions of low temperature and windy weather, and is different from common ventilated embankment in nature.2. The theory model of ventilated embankment with porous tubes inside was presented. Coupling problem between fluid and solid was solved by Brinkman model in the region of porous media; Fluid and porous medium were looked as two kinds of different continuous media, and on the basis of local non-thermal equilibrium theory average temperature of solid phase and gas phase was defined in REV; Heat transfer in porous medium was looked as the exchange of heat between solid phase and gas phase; Double energy equations were solved by means of sequential coupling.3. The phase change phenomena of frozen soil were simulated based on Characteristics of Heaviside staircase function and Gaussian jump function, and convergence and stability were improved.4. The temperature characteristics of the ventilated embankment with porous ventilated tubes inside, common ventilated embankment and common embankment were simulated under two different climatic conditions, and the calculated results indicate that two kinds of ventilated embankments heighten the upper limit of frozen soil. The better one is the ventilated embankment with porous ventilated tubes inside.5. Governing differential equations of ballast embankment were presented and modeled based on the model of the ventilated embankment with a porous ventilated tube inside. The calculated results indicate that ballast embankment can heighten the upper limit of frozen soil to protect the frozen soil.