防雪栅对铁路路堑风致雪堆积防治效果研究

Study on Effect of Snow Fences in Preventing Wind-induced Snowdrift on Railway Cuttings

针对铁路路堑易发生严重积雪灾害的问题,采用风洞试验方法,研究了防雪栅在减轻风致积雪灾害方面效果,为铁路线路防灾工程设计提供参考。在风洞中,首先分别试验了在6.5、7.5、8.5 m/s风速下边坡比为1∶4和1∶1.5的路堑内雪粒堆积演化过程;然后布置防雪栅,在相同试验条件下观测其在减轻路堑积雪灾害方面的效果;最后根据测量数据计算对比有无防雪栅时路堑路面积雪量差异,定量评估防雪栅防治效果。此外,采用数值模拟手段分析防雪栅、路堑周围流场变化情况,进一步解释防雪栅的防雪机理。结果表明:上风侧坡度较缓的半开敞式路堑积雪严重;防雪栅能有效减轻路堑积雪灾害;漂移雪粒首先在背风侧距离防雪栅较远处沉积,随吹风持续积雪范围向两端延伸;防雪栅使来流风速在其背风侧急剧减弱致使漂移雪粒发生沉积,雪粒输运强度减小,从而实现挡雪减灾目的。

Aiming at the serious snow disasters on railway cuttings,wind tunnel test method was used to study the effect of snow fences on reducing wind-induced snow disasters,which provides reference for practical disaster prevention engineering design of railway line.In the wind tunnel,the process of snow accumulation in the cuttings with a slope ratio of 1∶4 and 1∶1.5 was first tested at 6.5,7.5 and 8.5 m/s.Under the same test conditions,the effect of reducing snow deposition in the cuttings was observed after snow fences were built.Finally,the difference in snowdrifts on the railway and in the railway cuttings with or without snow fences was calculated and compared according to the measurement data,to quantitatively evaluate the effect of snow fences.In addition,numerical simulation methods were used to analyze the changes of the flow field around the snow fences and cuttings,further explaining the snow prevention mechanism of snow fences.The results show that the semi-open cuttings with a gentle slope on the windward side has serious snow accumulation problems.The snow fences can effectively reduce the snow accumulation in the cuttings.The drifting snow first deposits on the leeward side farther away from the snow fences.As the wind blows,the snow accumulation continues and extends to both ends.The snow fences sharply reduce the incoming wind speed on their leeward side,resulting in the deposition of drifting snow and the reduction of the snow transport intensity,thereby achieving the purpose of snow disaster control and prevention.