青藏铁路沿线滑坡泥石流灾害风险分析

Risk analysis of landslide and debris flow disasters along the Qinghai-Tibet Railway

以多重风险评估方法为基础,运用自然灾害风险研究的理论和风险评估模型,结合青藏铁路沿线历史灾害数据、地图数据、气象数据以及实地调查数据等,建立了滑坡、泥石流灾害历史致险性和潜在致险性的分析方法,构建了以2014年青藏铁路沿线数据为基础的物理暴露、应灾能力和脆弱性分析指标体系。通过对相关24项指标体系综合分析计算,得出青藏铁路沿线滑坡、泥石流灾害综合风险图。结果显示:青藏铁路沿线滑坡、泥石流灾害高危险区有5个区段,西格段西宁-湟源路段、关角山隧道附近以及格拉段的拉萨河谷路段滑坡、泥石流灾害风险最高;当雄-羊八井、安多-那曲路段以及唐古拉山-温泉路段属于中等风险;青藏铁路全线较低风险的路段有3段,分别是青海湖盆地的海晏-天峻路段、柴达木盆地的锡铁山-南山口路段、青南高原的昆仑山口-清水河路段,说明格拉段自然灾害风险大于西格段,西格段滑坡和泥石流分布比较集中,威胁路段较短,而格拉段滑坡和泥石流分布较为分散,威胁线路较长,其风险高于西格段。总体来看,青藏铁路沿线滑坡、泥石流集中分布在山区路段,高原面、盆地、宽谷路段线程长、区域广,绝大多数路段基本没有滑坡、泥石流等灾害威胁。从分析过程和结果来看,笔者认为青藏铁路沿线滑坡、泥石流灾害的致险性与风险的分析结果能较好的吻合,说明在青藏铁路沿线滑坡、泥石流风险评估的结果中,致险性占主导因素。从总体分布情况来看,地势平坦的地方均处于低风险区,说明沿线地形因素是滑坡、泥石流灾害的关键要素之一。

Landslide and debris flow are considered the third nature disasters in the world. Qinghai-Tibet railway is of high risk,so it is very important and necessary to assess the risk of landslide and debris flow disaster accurately and objectively for avoiding harm from disasters. Based on the theory of natural disaster risk research and risk assessment model,selecting 24 landslide and debris flow disasters along the Qinghai-Tibet Railway and historical disaster data,map data,meteorological data and field survey data along the Qinghai-Tibet railway,and by using the method of Multi-risk assessment,this paper established an analysis method for historical risks and potential risk of the landslide and debris flow,built an analysis index system for physical exposure,vulnerability and disaster response capacity based on the data of Qinghai-Tibet railway in 2014,and worked out a comprehensive risk map about landslide and debris flow disasters along Qinghai-Tibet railway. Results show that the high-risk group of landslide and debris flow disasters along Qinghai-Tibet railway has five sections. Therein,in section of Xining-Golmud,Xining-Huangyuan,near the tunnel of Guan-Jiao Mount and Lhasa Valley,the landslides and debris flows risk are the highest;in section of Damxung-Yangbajing,Anduo-Naqu and Tanggula Mount-Hot Springs,the landslides and debris flows risk are in middle level;the landslide and debris flow risk in the rest sections are low,which include three sections as section of Hai Yan-Tianjun in Qinghai Lake Basin,Mountain of Xitie-Nanshankou road in Qaidam Basin and Kunlun Pass Qingshui River in Southern Qinghai Plateau. It indicates that the natural disaster risk in Golmud-Lhasa section is greater than that in the west,the landslide and debris flow distribution in west section is concentrated and the threat section is shorter,while the landslide and debris flow distribution is relative dispersed in Golmud-Lhasa section and the threat section is longer. Overall,landslide and debris flow mainly distributed in mountain sections;for the Plateau,basin,wide valley sections,there is almost no landslides and debris flow disasters because of their long thread and wide area. The risk is consistent with the risk causing,indicating that the risk causing is the dominant factor in risk assessment of landslide and debris flow. Besides,judging from the overall distribution,all flat areas are in low-risk areas,showing that terrain is another key factor in risk assessment of landslide and debris flow.