Research On Effect Of Wind Erosion Controlling Of Plate-insert Upright Sand Fence At Cuona Lake Section Of Qinghai-Tibet Railway

This paper focuses on the problem of sand disasters in railways in Qinghai-Tibet Railway,which is a typical railway of plateau,and use the most serious sand-hit road section—cuona lake as an example.The main research is on the multi-row high vertical sand barrier on the right side of K1533,according to the wind speed data and sand discharge amount data obtained from field experiments analyze the protective effect of sand prevention measures.In addition,the paper studies the protective effect of sand prevention measures under different wind speeds and wind direction conditions based on Ansys Fluent,which provides theoretical basis for the prevention and control of wind and sand disasters in the railway of the plateau.The main research results are as follows:(1)The high vertical sand barrier can significantly reduce the near-surface wind speed.The lower the height along the horizontal direction,the smaller the ratio of the wind speed after the barrier to the control point,the more significant windproof effect of the sand barrier.(2)Within the 3m height,the average wind speed after the second sand barrier is the smallest,and the average wind speed after the third sand barrier is the largest;the second sand barrier has the best windproof effect at 2m,5m and 8m behind each sand barrier.At 12m behind each sand barriers,the first sand barrier has the best windproof effect.(3)At different wind speeds,there is a good linear relationship between the logarithm of sand discharge amount and height in the control area within a height of 75cm.The sand in the sand flow is mainly transported to the ground.It will get good results by setting the height to about 30cm when setting up sand prevention measures.(4)The combined sand blocking rate of the three-row high vertical sand barrier exceeds 99.5%when the collection speed is below 13m/s,the comprehensive protection system which consists of multi-row high vertical sand barrier,stone square and gravel pressure sand can reduce the sand transport in the sand carrying flow by at least 99.97%.The effect of sand control is very significant.(5)According to Fluent simulation,the percentage reduction of wind speed was consistent with multi-row high vertical sand barrier at different wind speeds,the greater the wind speed,the greater the decrease in wind speed after the barriers;with the deepening of the protective system,the impact of sand barriers on near-surface wind speed is also increasing.Compared with the wind direction which is orthogonal to the sand barrier,when the wind direction is skewed by 80° with the sand barrier,the height is lower,and the wind barrier effect of the sand barrier is reduced more significantly.(6)Through the Fluent simulation,the sand blocking effect of high vertical sand barriers decreases as the wind speed increases.In extreme weather(the wind speed at the reference point 2m height is 28m/s),the combined sand barrier rate of the three sand barriers is 80.95%,which still has good sand-resistance effect;when the wind direction skews with the sand barrier,the sand moves in the direction of an obtuse angle where the wind direction and sand barrier intersect,resulting in a decrease in the sand barrier effect,and the sand blocking project is set to be perpendicular to the prevailing wind direction to exert the maximum sand-resistance effect.So set the sand prevention project to be perpendicular to the dominant wind direction so as to maximize the sand-resistance effect.