CHARACTERISTIC ANALYSIS AND KINEMATIC SIMULATION OF ROCKFALL ALONG SHEXING VILLAGE SECTION OF QINGHAI-TIBET RAILWAY

Three important traffic projects were built along Lhasa-Yangbajing section of Tibet. They include Qinghai-Tibet Railway, 109 national highway(G109) and the 6th national highway(G6), as well as a large number of transmission lines. However, the mountains in this area are high and steep, thus rockfalls frequently occur. The rockfall poses a great threat to the safe operation of transportation and transmission. At present, the analysis and prediction of rockfall hazards are mostly based on the two-dimensional method of topographic profiles, which limits the movement direction of rockfall and makes it difficult to effectively assess their impact range. To solve these problems, the authors take the rockfall along Shexing village section of Qinghai-Tibet Railway as an example. They analyze the distribution of fallen rocks, the occurrences of rock mass structural planes, the characteristics of dangerous rock areas, and the kinematic simulation of rockfall. They use the methods of field investigation, high-precision three-dimensional surface topography modeling based on UAV aerial photography, and three-dimensional numerical simulation of rockfall. Through the simulation, the influence range, the arrival probability, the dominant motion paths, the height and kinetic energy of the fallen rocks are obtained. The results show that the rockfall mainly threatens the transmission lines and 109 national highway, and have rarely effects on Qinghai-Tibet Railway and the 6th national highway. The relevant simulation results are also instructive for the determination of the extent, height and mechanical strength of the protection facilities for rockfall.