3:45 PM - 4:00 PM
[SVC30-08] Outline of driving test on ashfalls covered roads in Mt. Fuji
Keywords:Volcanic Disasters, Disaster Prevention, Disaster Management, Ash Fall, Road Traffic
Volcanic ashfall can impact the communities and social infrastructure, although it is unlikely to result in the loss of human life. The possibility of driving on ashfalls covered roads is an essential issue in preparing disaster prevention plans for evacuation, the passage of emergency vehicles, and secure logistics. On the other hand, there are few driving tests on ashfalls covered roads in Japan (Kyushu Regional Development Bureau in 2015, Kagoshima City in 2018, and Mt. Fuji Sabo Office, Chubu Regional Development Bureau in 2021). The possibility of driving and braking distance due to thickness of ashfall and slope have been verified those tests, but the number of cases is insufficient to be used as a reference for disaster prevention planning.
In this experiment, to verify the effects of volcanic ash grain size and thickness on braking distance and driving, courses were built in the parking lot of Fuji Hokuroku Park in Yamanashi Prefecture, and the experiment was conducted from October 22 to November 8, 2021. Moreover, approximately 70 organizations, including local governments, fire departments, police departments, and lifeline-related companies, brought their vehicles to conduct driving tests. Nineteen patterns of courses were set up with different grain sizes and thicknesses of volcanic ash in three courses: flat, sloped, and curved. The sloped course was set to a slope of 5%, an average slope in Fujiyoshida City since previous tests have shown slopes of 10% to 12%. We prepared fine-grained volcanic ash from Mt. Fuji (less than 1mm), coarse-grained volcanic ash from Sakurajima (about 2mm), and Hōei scoria from the 1707 eruption of Mt. Fuji (about 5~10 mm). For the flat course, we prepared dry conditions courses with volcanic ashes of each grain size at thicknesses of 1 cm, 5 cm, and 10 cm, and we also prepared wet conditions courses of the fine-grained volcanic ashes. A 20-30 cm thick scoria course was also prepared. We prepared 5 cm and 10 cm thick fine-grained volcanic ash and scoria courses in the slope course. The curve courses were set up 1 cm thick of fine-grained volcanic ash on a flat surface curve (R=30) and a downward curve(R=30) with a gradient of 2.5%. Nine vehicles were used in the experiment to examine the effects of different vehicle weights and drive systems. If the vehicle could not be driven, the test was conducted with metal or plastic chains attached to the drive wheels.
As a result of the experiment, front-wheel drive and rear-wheel drive vehicles could not run on volcanic ash of 10 cm or more, as in the previous results. On the other hand, all-wheel-drive vehicles could drive on any thickness of ash. The tendency of the braking distance was different depending on the particle size. In the future, we plan to analyze the test results in detail and use them for disaster prevention measures such as road closure criteria and evacuation route selection.
In this experiment, to verify the effects of volcanic ash grain size and thickness on braking distance and driving, courses were built in the parking lot of Fuji Hokuroku Park in Yamanashi Prefecture, and the experiment was conducted from October 22 to November 8, 2021. Moreover, approximately 70 organizations, including local governments, fire departments, police departments, and lifeline-related companies, brought their vehicles to conduct driving tests. Nineteen patterns of courses were set up with different grain sizes and thicknesses of volcanic ash in three courses: flat, sloped, and curved. The sloped course was set to a slope of 5%, an average slope in Fujiyoshida City since previous tests have shown slopes of 10% to 12%. We prepared fine-grained volcanic ash from Mt. Fuji (less than 1mm), coarse-grained volcanic ash from Sakurajima (about 2mm), and Hōei scoria from the 1707 eruption of Mt. Fuji (about 5~10 mm). For the flat course, we prepared dry conditions courses with volcanic ashes of each grain size at thicknesses of 1 cm, 5 cm, and 10 cm, and we also prepared wet conditions courses of the fine-grained volcanic ashes. A 20-30 cm thick scoria course was also prepared. We prepared 5 cm and 10 cm thick fine-grained volcanic ash and scoria courses in the slope course. The curve courses were set up 1 cm thick of fine-grained volcanic ash on a flat surface curve (R=30) and a downward curve(R=30) with a gradient of 2.5%. Nine vehicles were used in the experiment to examine the effects of different vehicle weights and drive systems. If the vehicle could not be driven, the test was conducted with metal or plastic chains attached to the drive wheels.
As a result of the experiment, front-wheel drive and rear-wheel drive vehicles could not run on volcanic ash of 10 cm or more, as in the previous results. On the other hand, all-wheel-drive vehicles could drive on any thickness of ash. The tendency of the braking distance was different depending on the particle size. In the future, we plan to analyze the test results in detail and use them for disaster prevention measures such as road closure criteria and evacuation route selection.