关键词: 关键词 白格滑坡, 潜在危岩体, D-InSAR, PFC2D, 稳定性分析

Abstract: At 4:00 am on October 11, 2018, a large-scale rocky landslide occurred in the Baige village of the Bolo Town, Jiangda County, Tibet Autonomous Region, which is located at the upper reach of the Jinsha River. During its sliding, a large amount of debris rushed downslope at a high speed and blocked the Jinsha River, forming a barrier dam. At 5:00 pm on the October 12th, the barrier dam was overtopped and gradually washed by the river to form a drainage channel. At 9:00 am on the13th, the dam was completely flushed open, accomplishing the flood discharge and reliving the danger caused by the landslide. At 5:00 pm on November 3, 2018, the trailing edge of the Baige landslide experienced a sliding rupture, which led to the debris flow, at a high speed, piled up the dam from the first landslide, blocking the Jinsha River again. The height of the second barrier dam was 50m higher than the first one, forming a larger barrier lake. The water level in the barrier lake was reduced by a diversion channel after the first landslide, which avoided the flooding. Based on fieldwork, the author, adopting D-InSAR, has been monitoring the unstable?rock of the trailing edge of the Baige landslide for 7.5 days with interruption. The surveillance?results indicate that there is a slight sliding on the upper side of the landslide and there are four major deformation regions on the upper edge of the landslide. Besides, four measuring data points, selected within four major formation areas, show that the deformation value is 200mm and the deformation rate on the landslide top reaches 300mm/day, which suggests that the current landslide is still not stable and has the risk of blocking the Jinsha River caused by the landslide. This thesis, using PFC2D, simulates the stability of unstable rock on the trailing edge of landslide under the influence of gravity, torrential rain, and earthquake and analyzes the landslide’s stability scientifically in terms of simulation results, aiming to provide references for relevant landslides’ prevention and mitigation in the future. The simulation results show that the unstable rock in the back edge of the landslide will still lose stability under the induced factors such as heavy rainfall and earthquake. It's necessary to take appropriate engineering measures such as slope cutting to administer the unstable rock, and the real-time monitoring and early warning system should be set up to eliminate the hidden danger caused by the slide of unstable rock blocking the Jinsha River again in time. At the same time, this paper also provides reference significance for further understanding the development and evolution process, also the deformation failure mechanism of landslide and debris flow in Alpine regions. It also provides theoretical guidance for emergency measures and disaster prevention and mitigation after a disaster occurrence.

Key words: Keywords Baige landslide, Unstable rock, D-InSAR, PFC2D, Stability analysis