The Study On Thermal Characteristics And Evaluation Method Of Snow-melting Pavement With Electric Heating Pipes

In cold winter,road traffic is easily affected by the snow or freezing.In this paper,electric heating pipes are embedded in the surface layer of the concrete pavement,which is used to melt the accumulated snow on the pavement.This method of melting is environmentally friendly and efficient,which is good for road traffic safety in winter.In this paper,through theoretical analysis and experimental research,the work which has been carried out is as follows:(1)The structure of the snow-melting pavement with electric heating pipes in the practical engineering is introduced.Based on some reasonable assumptions,the three-dimensional structure of the pavement is simplified to a two-dimensional model.Based on the two-dimensional model,using the linear heat source theory and mirror heat source method,a theoretical model for the snow-melting pavement's temperature is proposed.(2)The indoor heating experiments of the snow-melting pavement with electric heating pipes were conducted.The design and cast of the snow-melting pavement achieved the relevant national standards.The results of the temperature measuring of the pavement surface verified that the proposed theoretical model is reasonable.(3)Based on the experimental results,an empirical model for the snow-melting pavement's temperature is proposed.Comparing the advantages and disadvantages of theoretical model and empirical model,the theoretical model has a wide range of application but some errors;the empirical model has a narrow range of application but little errors.Based on the comparative analysis,the semi-experiential model of the snow-melting pavement is proposed which has the both merits of the two models.(4)In order to reduce the energy consumption and increase the energy utilization rate of the snow-melting pavement with electric heating pipes,the finite element model is established based on the pavement's two-dimensional model.On the basis of the previous heating experiments,the melting experiments of the snow-melting pavements were conducted,and the quality of the melted snow was measured to verify the finite element model.According to the finite element simulation,the effects of four influence factors(heating pipe's embedded spacing,depth,heating power wind velocity)on the energy consumption and utilization rate was analyzed.Combining the finite element model and the response surface method,two prediction models of total heading time and loss energy rate are established.Using genetic algorithm and regarding the prediction models as the adaptive functions,the optimum scheme design of the snow-melting pavement which can achieve the least time-consuming and energy-wasting is obtained.(5)The thermal characteristic values of the surface temperature of the snow-melting pavement—the average surface temperature(T_A)and the temperature nonuniformity coefficient(Cn)are proposed,and the new evaluation index(?)for the pavement's melting performance based on the two parameters is proposed.The effects of heating pipe's embedded spacing,depth,heating power and wind velocity on T_A and Cn are analyzed by the finite element model.The prediction models of T_A and Cn are established by the response surface methodology.Through regression analysis,the formula of temperature characteristic value(T_A and Cn)of?is established.The method which uses the snow-melting pavement's design scheme and wind velocity to predict and adjust the melting performance of the snow-melting pavement is proposed.