DDA analysis of the RCC modification for Pueblo dam

Pueblo Dam is a massive head buttress structure founded on horizontally bedded sandstone and shale. Prominent shale beds beneath the structure daylight in the spillway stilling basin excavation downstream of the dam. Due to foundation sliding concerns the stilling basin has been filled with roller compacted concrete (RCC). The DDA model was used to check the stability of the modified structure assuming that no cohesion was available along the base of the RCC-plug/stilling basin lining contact. The DDA method is most effective when the structures are below the limit of equilibrium and movement has started, unfortunately at this point the structure is failing. This is not the case at Pueblo Dam.