Numerical Simulation Study On Snowdrift Disaster Prevention Along Beijing-Zhangjiakou Intercity Railway

The phenomenon of snowdrift is frequent in many areas of China,and in severe cases,it has an extremely bad impact on the building structure and traffic routes,and it is easy to cause casualties or major economic losses.As an important mode of transportation connecting Beijing and Zhangjiakou,the Beijing-Zhangjiakou intercity railway is located in the mountainous and hilly area,and is prone to strong winds and snowfall in winter,which has the potential danger of snowdrift disasters.With the Beijing-Zhangjiakou intercity railway as the engineering background,it is necessary to study the impact of snowdrift disasters on the Beijing-Zhangjiakou railway and ancillary structures.Based on the wind and precipitation data in the Beijing-Tianjin-Hebei region,this thesis studies the spatial distribution of snowdrift disasters,the deployment effect of snow prevention facilities and the uneven distribution of wind-induced snow in the Beijing-Zhangjiakou intercity railway,and the main research results are as follows:(1)Analyze the formation mechanism of Snowdrift.Based on the wind speed data and precipitation data in the Beijing-Tianjin-Hebei region from 1969 to 2016,the snowdrift along the Beijing-Zhangjiakou intercity railway were analyzed,and the sections prone to snowdrift disasters were obtained.Among them,Zhangjiakou Station has a high wind level and is prone to snowdrift disasters,and the extreme wind speed and extreme snowfall along the Beijing-Zhangjiakou intercity railway are calculated during the 50-year reproduction period.(2)Through the fluid simulation software Fluent,the wind flow field simulation of the cube model is carried out,and the wind flow field distribution map around the cube is obtained at different wind speeds and wind direction angles,and the influence of wind speed and wind direction on the snow distribution around the building is indirectly analyzed,and the snow distribution law around the building is summarized.The influence of wind direction angle under extreme wind speed during the 50-year re-emergence period on the snow distribution of different roof structures was studied,and the snow distribution characteristics of different roofs under different wind directions were obtained,and suggestions were made for the revision of the current building load specifications.(3)Establish the actual size of the embankment model,simulate the embankment height,embankment slope and flow field around the embankment when the wind deflector and snow barrier are laid through the fluid simulation software Fluent,analyze the influence of the embankment height and slope and the deployment of different parameters of snow prevention facilities on the distribution of snow around the embankment,and then obtain the prevention and control effect of snow prevention facilities,and put forward reasonable suggestions for the prevention and control of snowdrift disasters of Beijing-Zhangjiakou Intercity Railway.This thesis studies the distribution of snow around buildings and in the roof area,and provides reference suggestions for the revision of snow load specifications on building roofs and the design of snow resistance of houses.In addition,the distribution of snow under different railway snow protection facility parameters is analyzed in order to find out which parameters can achieve the best snow protection effect,so as to ensure the safe operation of the railway,which is of great practical significance.