Research On Numerical Simulation Of Wind Blowing Snow At Railway Cut And Disaster Prevention And Control Engineering

Wind blowing snow take place frequently in Xinjiang,Inner Mongolia,The Northeast in north China region,Its affect as many as dozens of railway in the winter,which caused thicker snow on railway and blocking traffic,its leading to the train slow down and even stop,cause huge economic losses.Many scholars at home and abroad do a number of research and put forward that several engineering measures like retaining snow wall,block snow fence etc,to prevent wind blowing snow disaster.Retaining snow wall is an usual sturctures to prevent the railway wind blowing snow effectively,But the existing have been designed lack of theoretical guidance,most of them construct rely on experience,the common problem is height and position of the retaining snow wall was designed unreasonable,so that they can't work completely and the block effect of snow poor.Therefore,To research the mechanism of wind blowing snow,optimization the wind blowing snow setting parameters,put its prevent snow to achieve the best results,make sure the railway safe operation whitch is very important for science and reality.This article research to cutting which is the pypical wind blowing snow of railway area,And with method of fluent optimization design,Combined with previous research materials,To compare net air through the cutting when its smooth change with mixed snow air,Explore the snow accumulate in cutting,And provide the theoretical basis for the snow protection.the paper has carried the simulation study for the first time about the movement characteristic of the wind-snow two phase flow at the leeward side of snow retaining wall under different height of snow retaining wall and different snow speed,and the optimization design of snow retaining wall.Analyze the flow field characteristics of the leeward side of the retaining snow wall,Made the design of the retaining snow wall should be a reasonable parameter in accordance with the flow field characteristics and the amount of snow within the cutting.The main contents of this paper are:(1)This paper introduces the causes of wind blowing snow and the influencing factors to cutting,Discussed the principle of snow starting and snow accumulation,Several theoretical methods and common practical measures for preventing snow and snow are put forward.(2)Toanalysis of the snow particles force,and establish the differential equations of motion of individual snow particles,selecting eulerian two-fluid unsteady model,thenestablished the turbulence k-? two-equation model of snow-snow two-phase flow,At last,used SIMPLEC algorithm tos olve the problem.(3)Used FLUENT to simulate the flow field characteristics of the wind around the road and the snow,The results show that:Compared with the net wind,snow turbulence area is smaller,but the low-speed area affected by the scope of the wind than the wind.Snow flow through the snow wall after the air separation,Into turbulence into the air movement is very complex,the wind-snow-flow rate decreases,so snow particles are deposited on the bed that the road through the snow flow for the lack of saturation state,reducing the amount of snow particles entering the cutting.When the near ground wind speed is greater than the snow particle starting wind speed,the snow particles deposited on the bed are re-energized by the airflow;When the near ground wind speed is less than the starting wind speed,part of the movement of snow will gradually deposited down,stacked snow particles will not be blown again by the wind,but against the location of the air from the role of obstruction,so that more snow particles deposited.Snow particles and air flow through the mutual influence of their own speed and movement characteristics which form a feedback mechanism.(4)The influence of simulated wind snow wall parameters on its leanage field characteristics:When the snow wall is located at different place which n the flow and the line under the conditions of vertical,the velocity of snow flow v=15m/s,and when the height of the snow cover is H =4m.The result is,When the distance from the line of snow when the snow wall L = 30 m then the effect is best.When the height of the snow wall is different,Its leeward side of the air flow in the range of the height of the snow wall is low speed turbulence zone.Height height of 0.5m above the height of the snow wall is acceleration zone,moreover,more closer to the snow wall,the more obvious the acceleration effect.When the height of the snow wall is less than 2.5m,leeward side of the snow area is shorter and with poor snow resistance.The higher the snow wall means stronger the ability to resist snow,but the snow wall to withstand the wind load is also greater and its own stability is also worse.Therefore,Should be multi-channel layout,and avoid increasing height in the design of the retaining snow wall.When the rate with the increase in wind speed lead to turbulence intensity is gradually increasing,at the same time,the ‘Big scroll' gradually downward wind direction indicating that the length of snow on the leeward side of the snow wall gradually increased.Therefore,Consideration should be given to the effects of wind speed when design the retaining snow wall.The greater the wind speed,the distance from the snow cover is also greater,which can determine the height of the snow wall and the distance from the line.(5)When design the retaining snow wall,should according to the actual situation to determine the appropriate snow wall of the material.The design of the retaining snow wall is highly recommended 2.5m~3.5m.When the average winter wind speed is 10m/s~15m/s,its should be arranged in the windside side of the wind between 20m~25m.When the average winter wind speed is 15m/s~25m/s,its should be arranged in the windside side of the wind between 25m~35m.When the average wind speed is greater than 25m/s,In the snow-rich and terrain open flat snow area,should be arranged in a multi-channel measures.