Effect of abutment movements on nonlinear seismic response of an arch dam

Abstract

Abutment movement that induces a reduction of the valley width in the periods of initial impoundment has been observed in a few high arch dams. In this article, the effect of the abutment movement on the nonlinear dynamic response of arch dams subjected to strong earthquakes is studied. The 285.5 m high Xiluodu arch dam is analysed. The results show that the abutment movement of 65–110 mm after initial impoundment leads to upstream displacements and a significant increase in compression stress in the arch dam under static conditions. When subjected to strong earthquake, the abutment movement results in a much larger opening of contraction joints in the middle part of the dam and prevention of opening of the other joints on both sides. Additional damage cracking is likely to occur in the surface outlets and the mid-level orifices. The damage cracking on the dam–foundation interface appears to propagate from the upstream face towards downstream, especially near the abutments where it extends one fourth thickness of the interface and is possible to damage the grout curtain.