Abstract:
The safety of concrete arch dams depends to a large extent on the soundness of the
foundation rock mass. The large arch dams presently under design and construction apply very
significant loads to their abutments and foundations. The assessment of the foundation stability
requires the analysis of the potential failure mechanisms defined by the major rock mass
discontinuities and joint sets. For dams located in areas of intense seismic activity, the analysis
needs to take into account the potential effects of earthquakes, not only on the concrete arch,
but also in the nearby rock discontinuities. The discrete element method is a major numerical
tools for discontinuum modelling, allowing the analysis of block systems defined by multiple
joint planes. In the paper, the key issues involved in its application to arch dam foundations are
reviewed. In particular, the representation of the discontinuities in models intended for failure
analysis is discussed. The evaluation of safety factors under static loading is addressed. The
framework for seismic analysis of arch dams is also examined, namely the dynamic boundary
conditions. Options to analyse the dynamic dam-water interaction and model calibration issues
are discussed, based on practical examples.