EXTRACTION METHOD OF IMPORTANT ROAD SECTIONS TO REDUCE ISOLATION RISK DURING EARTHQUAKE IN A MOUNTAINOUS AREA

Abstract

 Isolation of small hamlets may occur in mountainous areas due to road blockage induced by slope failure during an earthquake. In this study, we developed a method to systematically extract the road sections that should be prioritized when taking measures to reduce the isolation risk of hamlets. The road network is modeled as a graph consists of nodes and links, and the critical degree of each link is calculated. The critical degree of a link was defined as a value obtained by multiplying the population isolated when the link was blocked by its probability of closure. Through a case study, it was shown that the isolation risk of hamlets could be effectively reduced by preferentially reinforcing links with a high value of the critical degree.