Study On Hazard Assessment Of Debris Flow And Its Impact On The Planned Railway In Parlung Zangbo

Affected by the uplift of the Qinghai-Tibet Plateau,the topography of the Parlung Zangbo River basin is enormous,the geological structure activity is intense,and the lithology is broken.In addition,the study area has humid climate and abundant precipitation.The developed dynamic landform,abundant loose material source reserves and water supply lead to the development of disaster-inducing environment of debris flow.The debris flows along the Parlung Zangbo river seriously threaten the planned railway line and the personal safety of residents,which is easy to cause large economic losses.In order to identify the development characteristics and disastercausing ability of debris flow in the region and assist the selection of the planned railway line,this paper takes the small hydrological watershed as the evaluation unit to evaluate the susceptibility and risk of debris flow in the Parlung Zangbo River basin at the regional scale based on the field investigation and remote sensing interpretation.Taking the Tianmo gully debris flow,a typical glacier debris flow,as an example,this paper predicts the disaster-causing scale and disaster-causing ability of debris flow in100 years rainfall return periods,and comprehensively analyzes the influence of debris flow on the planned railway.The results are as follows:1.Based on field investigation and interpretation with remote sensing image,the spatial distribution characteristics of debris flow in the study area are revealed;2.Considering the influence of glaciers on the development of debris flow,a light and efficient index system for debris flow susceptibility assessment is constructed with the formation conditions of debris flow,and the debris flow susceptibility assessment is carried out in the Parlung Zangbo River basin.The spatial pattern and distribution law of debris flow susceptibility are revealed,and the map of debris flow susceptibility zoning in the Parlung Zangbo River basin is drawn.3.From the view of debris flow formation,a set of debris flow hazard assessment index system and assessment model with physical significance are constructed by comprehensively considering disaster-causing ability of debris flow and its formation process which includes the source initiation,movement process and accumulation.Taking the Parlung Zangbo River basin as an example,the debris flow hazard assessment is carried out,the spatial pattern and distribution law of debris flow hazard in the study area are revealed,and the hazard assessment results of Parlung Zangbo River Basin are drawn.4.Taking the typical glacial debris flow named Tianmo gully debris flow as an example,the finite difference method is used to predict the disaster-causing scale and disaster-causing ability of the debris flow in 100 years rainfall return periods considering the glacial development and hydrological conditions of the glacial debris flow.The influence of the typical glacial debris flow on the planned railway is analyzed,and the suggestions for the selection of the planned railway are put forward.This paper analyzes the influence of debris flow on the proposed railway from the perspective of the formation process of debris flow,and provides auxiliary decisionmaking for the route selection of the proposed railway in the Parlung Zangbo River basin,and provides scientific support for the government’s disaster prevention and mitigation.