Two-dimensional DEM-FEM coupling analysis of seismic failure and anti-seismic measures for concrete faced rockfill dam

Abstract

The concrete faced rockfill dam is composed of granular materials and the failure pathways typically exhibits multi-scale mechanical behavior. In this paper, a 2D polygonal DEM-FEM interface coupling analysis program is developed and introduced to the failure analysis of a 100 m high CFRD under strong earthquake. The polygonal DEM is developed to describe the strong-nonlinearity, large deformation and discontinuous of dam. The FEM and seismic wave input method is combined to simulate the dam-foundation interaction. A boned model is proposed to describe the deformation characteristics of face slab and anti-seismic measure. The results indicate that the initial seismic failure of CFRD occurs at the crest zone, and is characterized by the loosening, sliding and even rolling away of the shallow rockfill on the slope. Other initial failure modes include settlement of the dam crest, separation between the face slab and rockfill, downstream sliding of the wave wall and separation between wave wall and face slab. The installation of a nailed protective slab at the upper part of the downstream slope reduces the seismic damage by 27–41 %. The analysis method can intuitively reproduce the seismic failure mode and failure evolution of the CFRD and quantify the effect of the anti-seismic measure.