| Snow drifting is a typical natural disaster and can destroy the traffic system in cold regions. Researchers at home and abroad did numerous researches on engineering construction, but they didn't explain the mechanism of snow drifting perfectly. Most of their researches focused on traditional accessory engineering methods, such as snow-wall and snow-fence, and they didn't combine the mechanism of snow drifting and road snow drifting disaster prevention very well. In the JingYiHuo railroad snow drifting prevention project, our researches show that the mechanism of snow drifting are affected by lots of factors, and if one of the factors were changed, the others will change correspondingly. Furthermore the characters of railroad project are always the inducing agent of snow drifting disaster.In this paper, we adopt the typical snow drifting disaster areas, such as embankment, cutting, and semi-cutting, to field meteorological observation and testing including physical mechanics of snow cover and wind velocity of subgrade cross-section. We studied the formation of snow drifting and subdivided it into snow starting, snow transport and snow accumulation. Then we analyzed the formation conditions and influencing factors in each process and their relationship. Based on the new understanding of the characters and mechanism of snow drifting, integrating the idea that the area which wind speed reduces should be the area where snow drifting disaster occurs, we adopt numerical simulation to analyze how subgrade height (depth), slope ratio and incidence wind speed change railroad wind velocity field, then we can find out where the snow drifting disaster areas are. The results show that the numerical simulation wind velocity accorded with the actual observed value .when the embankment is less than 12m, higher embankment, smaller slope ratio and higher background wind speed can reduce the snow drifting disaster; and small slope ratio, high wind speed road-cutting and semi-cutting can reduce snow drifting disaster as well. Deep cutting and semi-cutting are propitious to storage snow, so they can reduce the snow disaster too.In summary, we pose the prevention methods for the railroad snow drifting disaster. That is:Designing reasonable subgrade is the key to reduce snow drifting disaster, and then planting grasses and trees, building snow-offence and snow-wall can help reduce snow drifting disaster more. This research result can offer reference for engineering construction. |
