Subjects: Geosciences >> Geography submitted time 2024-03-01 Cooperative journals: 《干旱区研究》
Abstract： The proposed Aerxiangou section of the Duku expressway, characterized by high mountainous terrain and canyons, faces frequent avalanches due to heavy snowfall and climate change. In this study, a collaborative investigation using UAV remote sensing interpretation and field research identified 92 avalanche points. In addition, elevation, slope, surface cutting degree, ground roughness, maximum snow depth, maximum wind speed, average temperature, and average snowfall were selected as driving factors. A geographical detector was used to examine the relationship between terrain factors, different resolutions, and avalanche stability. The results of this study revealed strong avalanche activity with generally poor stability in the study area. However, it was reassuring to note that most avalanche release and activity areas are located on mountain slopes. The accumulation area lies on the valley floor, a considerable distance away from the planned road route, thus minimizing its impact. Results from the geographical detector analysis suggest positive correlations between interpretations of slope and ground roughness with snow avalanche stability across varying resolutions. The interactive detection results are both double-factor enhancement and nonlinear enhancement, with the latter being more significant than the former. The combination of slope and other factors is crucial for determining the impact of avalanche stability. This study offers reliable data support for assessing avalanche vulnerability and risks, thereby establishing a solid scientific basis for constructing and operating the Duku expressway.
Subjects: Geosciences >> Geography submitted time 2023-12-16 Cooperative journals: 《干旱区研究》
Abstract： This study was implemented to accurately identify the avalanche flow characteristics and flow information, and comprehensively analyze avalanche motion. This study was based on UAV tilt photography technology to obtain high-resolution aerial photography data, taking the avalanche-prone area of Aerxiangou as an example. Through on-site investigation and UAV remote sensing interpretation to detect avalanche activity in a high-resolution manner, the goals were to determine the input parameters of the RAMMS model, to simulate and reconstruct different types of avalanche events on this basis, and to comparatively analyze the differences among the results of conventional ground-based investigation, UAV remote sensing interpretation, and simulation results to explore avalanche activity in different types and different snow layer release conditions. The results of the study show that (1) the avalanche investigation and analysis system based around tilt photography technology, which combines conventional ground- based investigation methods with UAV remote sensing and numerical simulation to verify each other, improves the accuracy of the assessment of disaster development status. (2) In mid- February, the snow on the slopes of Aerxiangou approaches the critical thickness value, and continuous snowfall destabilizes the snow layer and triggers new avalanches. The investigation is still in the disaster breeding stage, the snow layer cracks intensified deformation, the role of the wind snow eave self- weight gradually increased, there is more than the trend of the breaking strength of the snow, and the overall stability is poor. (3) In slope-type avalanches with a snow platform above the slope surface as the potential release area, the release volume can reach 8.2669 × 104 m3, the movement duration is about 128 s, and the flow height of the accumulation area peaks in 120 s at about 3.55 m, the flow velocity is about 18.34 m·s-1, and the impact force is about 32.67 kPa. In addition, the accumulation area is formed into an accumulation with an area of 3369.7 m2 and a volume of 1.8525×104 m3 of the pile. Through mutual verification, the slope-type avalanche does not involve release of the snow platform, and there is a discrepancy between the ground- based investigation results and numerical simulation interpretation results. (4) Trench-slope composite avalanches are released by fracture of the snow layer on the trench-slope, where the depth of fracture is only about 60% of the critical thickness value, the avalanche duration is close to 300 s in this case, and the impact range is 1178.5 m2 in the accumulation area, with an average accumulation depth of 1.64 m. The flushing-out volume is 3107.76 m3, the maximum flow rate in the accumulation area is 6.58 m·s− 1, and the maximum impact force is 17.97 kPa. The results of the ground-based investigation are roughly the same as those of the numerical simulation based on the 3D model. The results of the study have improved the accuracy with which avalanche event information can be acquired and can provide strong data support and a scientific basis for predicting future avalanche potential hazards, risk avoidance, and disaster emergency response.
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