Study On The Influence Of Wind Speed And Wind Direction Angle For Snow Drift On Expressway Embankment In Bashang Area Of Zhangjiakou

In winter,55.2% of China’s territory is located in areas affected by snow drifting disasters,such as the Northeast,Northwest,North China,and Southwest regions.The severe snow on highways not only causes traffic interruption,but also easily leads to traffic accidents and casualties.Due to the unique regional characteristics of the Bashang area in Zhangjiakou,snow drifting disasters on highway frequently occur.Domestic and foreign scholars have achieved many results in the study of snow drifting disasters,but there is relatively little research on the Bashang area in Zhangjiakou.This thesis combines the climate characteristics of the Bashang area in Zhangjiakou and uses ANSYS Fluent to conduct 3D numerical simulation of the flow field around highway embankments.It analyzes the influence of steady-state wind speed and wind direction angle on the wind speed,flow field distribution,and shear velocity of characteristic points on the embankment,and determines the upper limit values for the design of the most unfavorable inflow wind speed and road wind direction angle.Based on the size of the embankment in numerical simulation,establish an embankment model in a 1:50 ratio,conduct wind speed tests on the embankment model,and compare the measured results with the numerical simulation results to verify each other.Using wheat bran as a simulation medium for snow,conduct snow redistribution experiments to analyze the impact of transient wind speed and wind direction angle on the snow redistribution around embankments.This thesis provides theoretical reference for the selection and design of expressway routes in the Bashang area of Zhangjiakou.The main research conclusions are as follows:(1)The inflow wind speed v=9m/s is the most unfavorable inflow wind speed that causes the greatest degree of snow drifting disasters on highways in the Bashang area of Zhangjiakou.As the wind speed of the incoming flow increases,the degree of influence on the wind speed and shear velocity at the characteristic points in both directions of the embankment is greater,and the degree of improvement is greater,resulting in a continuous decrease in the snow area around the embankment.(2)There is a corresponding relationship between the wind speed weakening area and the snow particle deposition area,and the snow particle deposition area can better reflect the actual distribution of snow around the embankment.As the wind angle increases,the snow accumulation area around the embankment continues to increase.The upper limit design value of the wind direction angle for the road section where snow drifting disasters are prevalent in the Bashang area of Zhangjiakou is α=60°.(3)The wind speed variation law of embankment model is basically consistent with that obtained by numerical simulation.The error between model test results and numerical simulation results are less than 2m/s,which can be verified by each other within the allowable range.(4)The influence of transient wind speed and wind direction angle on the distribution of snow accumulation around embankments follows: 1)As the incoming wind speed and wind direction angle increase,the degree of snow erosion on the windward side continues to increase,and the degree of snow deposition on the road surface and leeward shoulder continues to decrease,and the degree of erosion continues to increase.The degree of snow deposition at the foot of the leeward slope continues to increase;2)As the incoming wind speed increases,the distribution of snow on the road surface and leeward side is more affected by the length of the highway;3)As the wind angle increases,the redistribution of snow at various locations on the embankment is less affected by the length of the highway.