铁路沿线雪害形成机制及其工程防治措施

Formation mechanism of snow disasters along railways and their engineering prevention and control

实地调查、观测和对铁路沿线气象要素的分析与推算结果表明,在所研究的丘陵地区,最大风速平均值为14.0m/s,30年一遇的最大风速与最大积雪深度分别为20.3m/s和160cm,冬季平均降水量达153 2mm,为风吹雪灾害的发生提供了物质与动力条件。在风吹雪多发区,路堤防风吹雪的适宜高度为200～1500cm,路堤若低于200cm,路面易形成风吹雪沉积;若路堤的边坡较陡,则路面不易形成风吹雪沉积;路堑边坡的角度越小,路堑越深,路堑走向与主导风向的夹角越小,风吹雪沉积越不易发生;风吹雪的防治应以防风吹雪走廊和下导风板为主,并辅以侧导板、挡雪墙等防雪工程。雪崩灾害主要发生在崇山峻岭区,阳坡雪崩危害相对较小;阴坡雪崩危害大。铁路选线时明线工程最好选在阳坡,永久性建筑物或设施要尽量避开沟槽雪崩的运动区和堆积区。在所有的隧道出入口,隧道要再向外延伸3m,上方修建导雪堤;在工程建设过程中,要求尽少破坏铁路两侧的植被。

By field observation and laboratory investigation,the meteorologic elements and wind field changes along Jinghe-Yining Railway are analyzed. Results indicate that the mean value of the maximum wind speed is 14.0 m/s, the maximum wind speed and the maximum snowcover depth occurring once every 30 years are 20.3 m/s and 160 cm respectively, and the average precipitation in winter is 153.2 mm. It is considered that the suitable height of subgrade for preventing drift snow disasters is in a range of 200～1500cm, and the drift snow deposition can easily occur on the pavement if the subgrade is lower than 200 cm; the drift snow deposition may not occur if the subgrade slope is steep, the cutting slope is gentle, the cutting is deep, and the angle between the cutting strike and the prevailing wind direction is small. It is suggested to prevent and control drift snow disasters with corridors and lower wind-guiding boards mainly, and with side wind-guiding boards, walls for blocking drift snow deposition, etc.,secondly. Avalanche ocoures mainly in mountain region, avalanche occurred at south side of hill has low hazard, oppositely,avalanche at north side is more dangerous than that at south side. Railway should be built at south side of hill in these region, the buildings and facilities should be far away from the active area of the avalanch. At the opening,the tunnel should be elongated about 3 meters and guide-dike should be built at up-side; during construction of the project,the vegetation should not be destroyed.