基于MDT的地震滑坡道路可通行性空间分布快速评估方法研究

Rapid Evaluation of Road Traffic Capacity with Influence by Earthquake-induced Landslide Using MDT

摘要:

如何预测地震滑坡道路可通行性空间分布是快速评估中的一个难题,为解决这一问题,本文提出一种基于MDT的地震滑坡道路可通行性空间分布快速评估方法。该方法包括3个步骤:①定制路段单元,将路段作为地震滑坡道路可通行性评估的基本单元,利用GIS将评估区内的道路划分成路段,制作每条路段两侧180m的缓冲区;②对路段进行地震滑坡属性赋值,统计各缓冲区范围内不同地震滑坡敏感性水平的像元数量,将统计结果作为对应路段的地震滑坡属性;③路段可通行性空间分布推断,利用MDT模型计算道路可通行性,最后进行地震滑坡道路可通行性空间分布制图。利用该方法对我国2008年汶川M_S8.0、2014年鲁甸M_S6.5和2012年彝良M_S5.6、M_S5.7地震灾区进行研究。其中,汶川地震灾区用来进行地震滑坡道路可通行性空间分布快速评估方法的建立和方法有效性的评价,鲁甸地震灾区和彝良地震灾区则用来对所建立方法在相似区域可移植性的评价。通过计算P值来检验模型的统计学显著性,并通过计算kappa值来评价模型反演结果与实际情况的一致性。结果表明模型计算出的道路可通行性是判断地震灾区道路是否因地震滑坡中断的良好指标;在允许一定误差的情况下,利用MDT模型进行地震滑坡道路可通行性空间分布快速评估的方法可以移植到其他相似区域。

Abstract:

The evaluation of roads damage and the traffic function state have a very important impact on the earthquake relief work. The decision-maker can make a better reasonable and effective earthquake relief strategy with a better understanding of the road traffic capability conditions. However,this question has long been plaguing scientists engaged in the earthquake disaster risk assessment. So far there is no better solution yet. To solve this problem,the authors develop a new method of rapid assessment of the traffic capacity(TC)mapping influenced by EIL using MDT. The method consists of three major procedures:①Customizing road section(RS). The RS is regarded as the basic unit of the TC evaluation influenced by EIL. On GIS platform,roads in the study area are divided into basic units,in which a buffer(180m)for each RS is created;②Calculating the number of each earthquake-induced landslide susceptibility level's cells on every buffer. The calculated results are taken as the RS's landslide attribute;③Using MDT to make TC map. To test our new model,four historical earthquake events,i.e. 2008 Wenchuan,Sichuan M_S8.0 earthquake,the 2014 Ludian,Yunnan M_S6.5 earthquake;and the 2012 Yiliang,Yunnan M_S5.6 and M_S5.7 double earthquakes,are selected for the case study,in which the Wenchuan earthquake case is for testing the effectiveness of our new model. The other two cases serve for testing the practicability of our model for the future earthquake disasters in other places in China. P-value and kappa coefficient were used to examine the model's statistical portability. The results show that the computed TC values are good indicators of blocked-road occurrences,and the MDT can be extrapolated to other study area and the developed approach can be used in various magnitude earthquake events.