The Stability Of High Rock Slope About Fudang Tunnel Of Lhasa-Shigatese Railway And Its Transect Line Control

The new Lhasa-Shigatese Railway located at latitude 29°00’～29°30’, longitude 89° 25’～90°45’, at the Qinghai-Tibet Plateau of southwestern China. The railway goes up to west along the Brahmaputra, passing through the Brahmaputra Canyon Area and geothermal area, facing the challenge of numerous of geological issues such as high rock slope stability issue and high geothermal phenomena.This paper studies the new Lhasa-Shigatese Railway Fudang Tunnel. Based on abundant references and a profound understanding on the regional geological setting of the study object, combined with the site geological survey, a systematic analysis and summary was concluded on the geological development condition, mechanics characteristic and on relevant factors of high and steep slope in Brahmaputra Canyon area. And a comprehensive analysis on the high geothermal phenomena in that area and on the unsymmetrical pressure phenomenon which accompany with tunnel construction was drawn in this paper as well.With the application of Barton Model Method, the mechanical parameter of the rock mass structure was confirmed. Combined the Stereographic Projection Method with Finite Element Analysis Method, an analysis of the stability of high rock slope was given. Further, the unsymmetrical pressure condition of the tunnel body was analyzed in manner of applying Finite Element Analysis Method and Mechanical strength analysis Method.Based on the above mentioned analysis, a differential stress contour map was drawn to compare the tunnel body unsymmetrical pressure at recommended location with the tunnel body unsymmetrical pressure at outward & inward location. And with the application of Finite Element Analysis Method, the geothermal forecast would be respectively given on the recommended tunnel location and the outward & inward tunnel location. Combines the geothermal forecast conclusion with the above mentioned analysis on the unsymmetrical pressure, a comprehensive analysis on the three tunnel locations will be given to line comparison and selection to confirm the optimal tunnel location and be given as reference to relevant projects.