Geomorphological Spatial Model of Risk Analysis for Natural Disasters in Heritage Railway Tunnel

Abstract

Flood event in Ijo Tunnel led to disruption to schedules and train routes. The objectives of this research are to determine the susceptibility, vulnerability, capacity, and risk, to analyze the geophysical and geotechnical condition, and to compile the strategy of disaster mitigation of Ijo Tunnel. A spatial approach based on landform analysis was performed to establish the disaster components. Geophysical and geotechnical investigation was conducted to describe the condition of the affected region. A field survey was accomplished to collect data and to study supporting works of literature. The descriptive analysis was completed to determine strategy and recommendation in flood and potential landslide mitigation. The result depicts that Ijo Tunnel holds multi-disaster risk such as floods and landslides. The occurrence of floods is induced by extreme rainfall and inability of drainage channels to retain water. The landslide potential is influenced by morphological factors and composting materials in Ijo Tunnel’s region. The existence of spring fracture on the north slope also contributes to increasing the slopes’ landslide potential. The flood mitigation measure can be carried out by building a well-prepared drainage system and watershed and surface runoff management. Areas with a high level of landslide susceptibility can be overcome by building permanent retaining walls and pipes on slopes to reduce the soil saturation level.