17:15 〜 19:15
[AHW22-P11] Rockfall Susceptibility Analysis of Taiwan's Forest Roads Using RHRS Risk Assessment
キーワード：Hazard, Rockfall, RHRS, Slope Unit
Jun-Da Forest Road, located in Xinyi Township, Nantou County, Taiwan, is a popular route for hikers and campers, particularly after the COVID-19 pandemic in 2020, which leed to a surge in outdoor recreational activities. However, the road traverses geologically sensitive areas, making it highly susceptible to rockfalls, landslides, and fallen trees, especially after heavy rainfall and typhoons, the sole access route and its narrow road width increases the disaster risks. Although slope stabilization techniques have advanced, the increasing frequency and intensity of rainfall have resulted in recurrent slope hazards, making road safety maintenance increasingly challenging. therefore, risk assessment for mountainous areas is a critical issue.
This study integrates hazard, vulnerability, and exposure factors with the Rockfall Hazard Rating System (RHRS) developed by the U.S. Federal Highway Administration to assess rockfall disaster risks. First, numerical terrain and rainfall event data are collected to compute landslide susceptibility values using a Geographic Information System (GIS) as the hazard indicator. RHRS is applied to evaluate slope vulnerability based on factors such as slope height, rock roughness, roadway width, rockfall history, frequency, magnitude, and engineering conditions. Second, exposure indicators are derived by estimating average daily traffic volume, vehicle length, and speed using established formulas. At last, the analysis is conducted using slope units as the primary evaluation basis, where hazard, vulnerability, and exposure indicators are weighted equally and multiplied to determine the total risk value. The study validates its findings using construction road safety inspection result data and compares them with previous studies that assessed risk based solely on landslide susceptibility using road mileage as the analysis unit. Results indicate a projected accuracy improvement of 5–15%. GIS-based visualization is employed to enhance interpretability. The findings aim to provide a more detailed and accurate risk assessment framework, offering regional management agencies a scientific basis for effective design and maintenance strategies.
This study integrates hazard, vulnerability, and exposure factors with the Rockfall Hazard Rating System (RHRS) developed by the U.S. Federal Highway Administration to assess rockfall disaster risks. First, numerical terrain and rainfall event data are collected to compute landslide susceptibility values using a Geographic Information System (GIS) as the hazard indicator. RHRS is applied to evaluate slope vulnerability based on factors such as slope height, rock roughness, roadway width, rockfall history, frequency, magnitude, and engineering conditions. Second, exposure indicators are derived by estimating average daily traffic volume, vehicle length, and speed using established formulas. At last, the analysis is conducted using slope units as the primary evaluation basis, where hazard, vulnerability, and exposure indicators are weighted equally and multiplied to determine the total risk value. The study validates its findings using construction road safety inspection result data and compares them with previous studies that assessed risk based solely on landslide susceptibility using road mileage as the analysis unit. Results indicate a projected accuracy improvement of 5–15%. GIS-based visualization is employed to enhance interpretability. The findings aim to provide a more detailed and accurate risk assessment framework, offering regional management agencies a scientific basis for effective design and maintenance strategies.