Rapid landslides threatening roads: Three case histories of risk mitigation in the Umbria region of Central Italy

摘要

The geomorphologic and geologic characteristics of the Umbria Region of central Italy,alongwith its urbanization,are the main cause of the widespread landslide risk. In the region,landslide risk is classifiedin a ranking between 1 and 4,where 4 is for the highest level. Shallow landslides,debris flows and rock-fallsare included in this highest level,since they are extremely rapid and intense. Many of these typologies oflandslide recently occurred in the Umbria Region of Central Italy affecting the major road network. Pilot studyareas were selected within the Region where important transportation corridors lie in the zone threatened byrapid landslides. This paper describes the risk mitigation strategies adopted for the selected roads and introducesthe crucial issue of the residual risk management. By presenting different situations,this paper shows how theregional authorities faced the problem,and tries to summarize the answer that they gave to the issue by combiningcountermeasure,information and maintenance actions.