Study On Air Cushion Effect Of High-speed And Long-runout Landslide Triggered By Earthquake

On May 12, 2008, an 8.0 M earthquake struck Wenchuan county, Sichuan province of China, causing a huge number of death and injuries, and great loss of properties. Due to the extremely high magnitude, long duration of vibration and complicated geo-environment in disastrous area, the earthquake triggered a huge number of rockfalls and landslides. Especially the high-speed and long-runout landslide, based on the air cushion effect, produced extremely severe geohazards.Based on the Donghekou landslide, which was the typical high-speed and long-runout landslide triggered by Wenchuan earthquake, using numerical wind tunnel test and numerical analysis method, this thesis has researched air cushion effect of high-speed and long-runout landslide. The research work and results involves several aspects as follows:1. Using the Fluent program, which is the Computational Fluid Dynamics software, the author simulates a former wind tunnel test model. By contrasting the numerical results with the previous entity model test results, the comparison is very satisfactory.2. The numerical model wind tunnel experiment aimed at air cushion effect of Donghekou high-speed and long-runout landslide has been accomplished. On the base of numerical testing research, the paper studies different factors which influence the air cushion effect of flying landslide.3. The paper puts forwards the differential equations in the course of flying of large high-speed landslide. Using numerical wind tunnel test results and numerical analysis method, this thesis has researched movement law of high-speed landslide affected by air cushion effect.The results show that the flying distance considering air cushion effect is more reasonable by comparison with the field observation. Because of air cushion effect, the flying time is longer and the flying distance is farther than those without consideration of air cushion effect. The study preliminarily reveals the dynamic features and movement law of high-speed and long-runout landslides triggered by earthquake, and provides the scientific bases for disaster prevention and reduction in seismic disastrous area.