Abstract: The geologic condition of the high inlet slope in the Zhexi Hydropower Station Extension Project is complex and the project is difficult to construct. A three\|dimensional FEM model, which includes three sets of crevices, two sets of the staggered rock layers and rock anchors, is established. The construction sequences are simulated in accordance to the actual construction procedure. The results show that the high inlet slope, diversion tunnel and strobe cavern are stable and the excavate construction procedures are reasonable and feasible. But the two sets of crevices and two sets of the staggered rock layers may affect the stability of the high inlet slope, diversion tunnel and strobe cavern. The supporting solutions for these potential instabilities are proposed in this paper. The monitoring results during the construction was validated the analytical results.

Key words: slope engineering, rock mass, numerical simulation, three-dimensional elasto\, plastic FEM, plastic zone