Research And Optimum Design Of Prevention Measures For Drifting Snow Disasters On Expressway

Drifting snow is a kind of multi-phase flow weather phenomenon that scattered snow particles are carried by the air flow and run near the ground.It mainly occurs in the northern and western plateau areas with high latitude and altitude in China.High intensity drifting snow will have a disastrous impact on long and large linear transportation facilities such as railways and highways.Because it is difficult to predict and control the drifting snow disaster itself,and most of the prevention and control measures are not set up in our country,the traffic is seriously blocked and even threatens people's life safety.Therefore,this paper makes a systematic study on the prevention and control measures of the drifting snow disaster on the expressway.Based on the background of a certain expressway in Chengde and Zhangjiakou,Hebei Province,and combined with the existing protective measures,this paper carries out the research on the snow prevention effect of two kinds of snow prevention measures,namely,the snow prevention wall and the wind guide plate,and establishes a prediction model of snow prevention effect considering multiple factors,and puts forward the optimization design method of the prevention and control measures In order to minimize the drifting snow disaster and provide technical support for specific projects.The details are as follows:First of all,the concept of drifting snow,the causes of drifting snow disaster,prevention and control theory and other related theories are summarized,and the common prevention and control measures are investigated.This paper introduces the basic theory of numerical simulation and regression orthogonal test of wind blown snow,which lays a foundation for the establishment and calculation of subsequent numerical model.Secondly,a series of preprocessing work is carried out,including the introduction of basic assumptions of numerical model,determination of wind speed,highway subgrade size,turbulence model used,mesh generation method,model calculation range,boundary condition setting and other parameters setting.Finally,according to the two different prevention and control measures of snow retaining wall and wind guide plate,under various subgrade cross-section forms,five influencing factors are selected respectively,namely,the average wind speed at the height of 10 m near the ground,the height of snow retaining wall(length of wind guide plate),the horizontal distance between snow retaining wall and subgrade(height of wind guide plate),the height of embankment(cutting)and the slope ratio,to determine the orthogonal table.After a lot of numerical simulation and sorting out the results,the test indexes are extracted.Then the regression orthogonal test is carried out to get a comprehensive prediction model of snow prevention(snow transportation)effect.According to the absolute value of each coefficient of the prediction model,the influence degree of each factor is obtained;at the same time,using the prediction model of snow prevention(snow transportation)effect,taking the influence factors of the prevention and control measures as independent variables,the optimization method of a two-dimensional curved surface to find the extreme value is proposed to optimize the prevention and control measures;and the prevention and control effect of the two prevention and control measures is studied,which proves that the feasibility and rationality of the optimization method of prevention and control measures proposed in this paper.