Analysis on development characteristics of debris flow and route selection countermeasures along the traffic lines in mountain areas of Western China

Affected by topography and tectonics, the eastern part of the Qinghai-Tibet Plateau is characterized by high density, diverse types and frequent outbreaks of debris flows.In order to provide support for the planning, selection, and later operation of the line engineering, we study the development characteristics of debris flows in the transportation corridor and their impact on the project.In this paper, through high resolution remote sensing interpretation, field surveys, and grain analysis tests, the types and distribution of debris flow in the study area have been systematically studied, and corresponding route selection strategies have been proposed.The results show that: ①Rainstorm debris flows and glacier debris flows are mainly developed in the study area, which has the characteristics of wide distribution, multiple types, large scale, and long disastrous chain.The adjacent lines are mostly rainstorm debris flows.②The study area has problems such as difficulty in investigating and identifying potential debris flow ditches, difficult design of disaster chain prevention and control, and harsh plateau construction environment.③The Sichuan-Tibet railway line selection should implement the risk control principle, take disaster mitigation line selection as the leading factor, and actively use InSAR, LiDAR, and UAV technology to conduct surveys on complex sources such as difficult source estimation and unclear identification of potential debris flow gully.The geological conditions of debris flow gully investigation should adopt the "air, space and earth" integrated comprehensive survey technology, and different types of debris flow should be combined with the characteristics of the debris flow to take diverse prevention and control measures.