The deformation of abutment slope during impoundment poses great challenges to the working behavior and long-term safety of the arch dam. According to the monitoring data of impoundment and slope, slope deformation, valley width change, and arch dam chord length change are systematically analyzed and studied. It is pointed out that the deformation of the dam body and foundation is an irreversible plastic deformation and is evidently correlated with impoundment. Based on the unsaturated effective stress principle of fractured rock mass and the action mode of the reservoir basin pressure, the deformation mechanism of abutment slope has been discussed. The large-scale 3D nonlinear finite element model is established based on numerical analysis, and the deformation mechanism during impoundment and the effect of the effective stress change on the displacement and stress of the dam body are analyzed. The results indicate that effective stress can elucidate the valley contraction to some extent and that the contribution of the reservoir basin pressure is small. Slope deformation is beneficial to the dam displacement to some extent. Moreover, it has a negligible influence on the dam surface stress. However, the junction of the dam and foundation needs to be given special attention.

Slip-friction of faults and joint fractures is of great significance in the study of rock mass structural engineering stability and earthquake generation mechanism. Laboratory friction experiment is a great method to determine the frictional strength of rock interfaces. A large number of low-velocity experiments has been conducted to explain the friction mechanism in the regime of direct shear mode. However, the friction mechanism in the regime of vibration mode has rarely been studied. To study the slip-friction mechanism of rock interface under the vibration mode, a dynamic friction experiment with two blocks on a vibrating platform was performed. The experiments were conducted with hard granite samples at a vibration frequency of 1–10Hz, vibration amplitude 0.5–5mm, and normal stress of 0.5–4.5MPa. The results demonstrate that slip- and frequency-weakening phenomena were noticed and the general quantitative relationship of the three characteristic friction parameters is μ 3 > μ 1 > μ 2. Moreover, the normal stress has a significant effect on the weakening degree of the friction coefficient, and the change in the surface roughness may correlate with the change in the weakening degree.

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