Minor landslides and floods events affecting transportation network in Switzerland, preliminary results

摘要

Roads and railways are threatened by several hazards all around the world, including landslides and floods, leading to the closing of transportation corridors, loss of access, deviation roads and potentially infrastructure damages as well as loss of human lives and also financial, social and economic consequences. Whereas large landslides—over 2000 m2 of area—affecting transportation networks are usually well documented and their consequences on transportation tracks are usually investigated in detail, minor landslide characteristics and consequences are not so well documented even though they are not negligible. Minor landslides on transportation networks are often man-induced, due to slope cut-and-fills. The aim of this study is to characterize minor landslides and floods affecting roads and railways and to evaluate their consequences on infrastructures, track users and authorities. We use data from the Swiss Federal Institute for Forest, Snow and Landscape Research WSL of earth flows, floods, debris flows and rockfalls affecting roads and railways from 1972 to 2014 in Switzerland and a database from the University of Lausanne with similar event types and also snow avalanches affecting roads and railways from 2012 to 2014 in Switzerland. The results shows that 96% of the events that affect roads and railways cause only low direct damage costs and can be categorized as minor landslides and floods events. However as they are numerous, they cost CHF 6 million each year representing 27% of the total event damages. On the long term, this cost is of the same order magnitude that the cost due to larger events but less frequent. The results of this study will be used to build a decision making tool.