HAZARD ASSESSMENT OF ROCKFALL AT YADONG BORDER PORTS IN TIBET

Rockfall disaster is an important geological environment issue for the Tibet border port traffic line. With the Yadong Port in Shigatse, Tibet as the research area, this paper carries out quantitative assessment of the hazards along major highways and the surrounding communities. Through remote sensing interpretation and field survey methods, information on historical rockfall disasters, the spatial distribution of dangerous rock masses along the route, topography, geology and stability status are obtained. Considering the controlled lithologyand terrain conditions formed by the rockfall, the identification of the source area of rockfall is realized based on GIS. Based on Holmgre's correction algorithm, inertial algorithm and friction loss function, Flow-R software was used to simulate the range of the rockfall movement and the threatened traffic zone at Yadong Port was determined. The results show that the coincidence of the scope of GIS identification in the source area of rockfall and the actual field survey is 76.9%, and the fitting precision of the range of the motion simulation and the actual rockfall rolling range is 60.3%. The simulated high-risk impact area accounts for 12.5% of the total study area. The traffic sections affected by the simulation are mainly distributed on the high slope slope body in the southwest direction of the Yadong Port, affecting the length of the road section more than 7000m. The number of grids with a falling rock reaching probability exceeding 0.7 is 2647,which accounts for 1.5% of the total number of grids in the rockfall simulation range, and is concentrated at the place where the curvature value at the bottom of the gulch is large. The research results of this paper have certain reference significance for the evaluation and prevention and control of the impact range of the rockfall of important traffic routes in Tibet port.