Seismic Analysis for the Foundation of a Tailing Dam in Peru

Cecilia Torres Quiroz,
Geomat Ingenieria, Lima, Peru, ctorres@geomatingenieria.com
Herbert Miguel Ángel Maturano Rafael
Geomat Ingenieria, Lima, Peru, mmaturano@geomatingenieria.com
Celso Romanel,
PUC-Rio, Río de Janeiro, Brasil, romanel@puc-rio.br

SUMMARY: The tailings dam studied in this paper is located in the department of Ayacucho, in Peru, a region of high seismic activity. The foundation consists of a surface layer of moraines and residual soil, followed by a layer of argillite material whose resistance increases with depth. The argillite stratum is deeper near the left abutment, and it is important to estimate its influence on the seismic response of the tailings dam. A simplified method consists in the selection of a representative profile characterized by the distribution of the shear wave velocity with depth. For the analysis of the dam behaviour, two models were used: a simple model for 1D seismic response based on the propagation of vertical shear wave through a layered viscoelastic medium and a 2D numerical model based on the finite element method and specific constitutive relationships for the different soil types. Results for 1D and 2D analyses are quite similar, although the 2D analysis permits a better accuracy because it includes topographical effects due to geometry of foundation site.