新亚欧大陆桥新疆段环境灾害分布规律

The Distribution of Environmental Disasters of Xinjiang Line in New Eurasian Continental Bridge

根据实地调查和收集到近四十年资料， 分析新亚欧大陆桥新疆段环境灾害成因、类型及成灾方式， 阐明了陆桥新疆段以洪水、风沙灾害为主要类型的灾害特点， 通过对不同灾害类型的时空强分布的统计分析， 揭示了灾害过程春季３～４ 月以盐碱土不良路基、风沙灾害为主， 夏季６～７ 月份以洪水为主的灾害时空活动特点和区域分异规律。

Various disasters, such as flooding, strong wind, sandy disaster, roadbed disasters and so on, often occurring along Xinjiang Line of the New Eurasian Continental Bridge, have seriously been affecting on the railway transportation. Flooding disaster, mostly takes place during Spring and Summer because of rainstorm and thaw snow water and often lead to roadbed sinking, train speed-limiting, even transportation ceasing. The flood could be occurred at 15mm/10min or 25mm/1h of day critical precipitation in Shanshan Railway Section, and above 30mm/d of that in Urumqi Railway Section. Windy and sandy disaster, in form of turning over train, digressing and burying railway line, is a particular type of disaster owing to several famous windy areas such as “Yandun windy area”, “Baili windy area” and “Sanshili windy area” in Shanshan and Urumqi Railway Sections. It is observed that the passes between hills in which the windy speed can reach to 8～12 grade because of windy accretion, are the key locations where often take place windy disasters. It is also discovered that sandy disasters could be occurred only when the windy speed of rising sand reaches above 6 m/s. Roadbed disasters, derived from clammy loess roadbed and salty-alkaline roadbed, taking the form of side-slope sliding, roadbed sinking and silt turning up owing to the seasonal changes of water and heat conditions, generally lead to railway-track transforming, train speed limiting, even transportation ceasing. This type of disaster, mainly distributing in Shihezi and Kuitun Railway Sections, takes place in Spring when the temperature rapidly rises to 10~15℃ and precipitation comes forth or in winter when the thickness of snow deposit on shade slope reaches above 20 cm. From the view of spatial distribution of disasters, Liuyuan section, accounting for 23 25% of total, is the most; Shanshan section, accounting for about 21%, is the next; Shihezi and Kuitun sections, respectively accounting for only 13 97% and 6 99%, is the least because this line just run for 11 years. But then, comparing the frequency and the density of disasters, the average of disasters occurring in Liuyuan section is actually not more than that in Shihezi, even Kuitun section, and Urumqi section is the top area not only in the density, but also in intensity. From the view of temporal distribution of disasters, the intensity of disaster taking place in 1990's is far stronger than that in the past years because the flooding disasters in this region tends to increase in the late 20th. a century. Most of disasters, about 57 57% of total, appear in July and June because the rain season comes up generally in these times. In addition, flooding disasters often come forth in June and July, and windy and sandy disasters mostly in April and roadbed disasters in Mar and April.