Inverse analysis on motion characteristics of "10·10" Baige landslide in Tibet

Abstract:

In order to obtain the movement law and characteristics of the "10·10" Baige landslide, based on the three zones (initiation zone, accumulation zone, and impact zone) and six stages of motion (instability and failure of the main body, initiation of traction zone, high-speeding slide in the air, impact on the opposite shore, turn-backing collision and jet of water and sand, and secondary slip of the pileup dam) of the Baige landslide, the accumulation state of landslide debris body and its impact shape in the other side of the river (in Sichuan Province) were analyzed. Adopting the calculation method proposed by Sheidegger and the energy transformation calculation method, five characteristic points considering impact height were selected to calculate the velocity of landslide debris body during each motion stage. Results show that the landslide initiated with a velocity of 2.2 m/s, and the velocity of the landslide body increased constantly from the initiation zone to the shear outlet. The maximum velocities of the five characteristic points were H₁ 67.0 m/s, H₂ 73.0 m/s, H₃ 73.7 m/s, H₄ 73.2 m/s, and H₅ 68.3 m/s, respectively. When the sliding body in the traction zone reached the shear outlet, the velocity was 70.2 m/s. The velocities in main slide zone and resistance zone gradually decreased from the middle to both ends, and the velocity was the highest in the main sliding direction of the landslide, up to 73.7 m/s. The energy released at least 10^10.8 J when the whole sliding body moved, causing vibration equivalent to the surface bedrock earthquakes of 4.0 to 4.7 magnitudes. The study of the motion characteristics of "10·10" Baige landslide on the basis of the geomorphic features of landslide impact will deepen the understanding of the kinetic mechanism of Baige landslide and provide reference for the prediction, mitigation, and prevention of similar geohazards.