Abstract: Having experienced 5·12 Wenchuan earthquake and 4·20 Ya’an earthquake, the left bank accumulation body in front of a hydro-junction has degraded in its stability and physico-mechanical parameters. Although the accumulation body is stable in general at present, its overall stability will have a significant impact on the safe and stable operation of downstream hydro-junction when similar earthquake occurs again. In view of this, we calculated the permanent displacement of the accumulation body under earthquake action by using FLAC^3D and Newmark Method. We conclude that the displacement of the accumulation body is mainly located in the small part above the pressure body, and the maximum displacement is 0.56m. Furthermore, we estimated the stability of the accumulation body according to the displacement and plastic zone. The accumulation body will still be stable as a whole under similar earthquakes, with only local shallow surface creep. The result offers a basis for ensuring the safe and stable operation of the downstream hydro-junction.

Key words: prediction of accumulation body stability, earthquake action, FLAC^3D numerical calculation, Newmark method, creep, mechanical parameters