Observation of the behaviour of Foz Tua dam during the first filling of the reservoir

Abstract

The Foz Tua Project is the latest accomplished hydroelectric investment of EDP - Energias de Portugal, located in a tributary of Douro River, close to its mouth, in the northeast of Portugal, which includes a concrete double curvature arch dam 108 m high with a total crest length of 275 m, closing a narrow granitic valley. After a brief presentation of the project, the monitoring system is introduced, reporting namely the automatically controlled remote observations. The overall characterization of the behaviour evolution is presented, noticing the perceived agreement between observations in redundant systems, as well as the sought correlation between related physical quantities. Furthermore, some minor inelastic behaviours related to local adjustments of the dam/foundation structure, as well as the improvements in the designed foundation drainage and piezometric networks which were implemented accordingly to the foundation hydraulic behaviour observed in the last impoundment stages, are also commented. Bearing in mind the adequate behaviour during the first filling of the reservoir and the good fitness of a nonlinear finite element model it was concluded that the dam is apt to the following serviceability state.