Canales Dam clay core

Emplacement

Canales Dam clay core, Granada
Spain

Monitoring of clay core using mutipoint extensometer

Système: 
System SOFO
Domaine: 
Domain Dams & Dikes
Clients: 
IIC
Début des travaux: 
2006
Fin des travaux: 
0
Installation: 
IIC
Courte description: 
The Canales Dam is built on the Genil River, in Granada, Spain. Itwas constructed during period 1975–1989, and exploitation started in 1989. The dam is 156m tall and the crown is 340m long. The dam accumulation is used to produce electrical power, but it is also an important tourist attraction, notably for people who like fishing. The Canales Dam controls the river flow duringthe year, ensuring that there is always sufficient water to keep the river ‘alive’ even during the driest months of July and August. A view of the Canales Dam is given in Figure 1.
Objectifs de contrôle: 
The aim of the monitoring has been crack detection and deformation of the stiff-clay core of the dam. The zone where the cracks can occur was estimated to be between 60 and 110 m deep in the clay core. This whole length was equipped with a 50 m long multipoint extensometer with 10 measurement zones (10 enchained 5 m long deformation sensors). Preparation of the extensometer for the installation is shown in Figure 2. The sensors were installed in a 110 m deep and 30 degrees inclined borehole using a purpose developed installation procedure and special setup. A mass with wheels was attached to the low-stiffness cord and slipped into the borehole. While the mass was pulling the cord into the borehole, the extensometer was attached to the cord, so the cord was used as a guide for the extensometer. The installation procedure is shown schematically in Figure 3. After the placement of the extensometer in the desired position, the boreholewas alternatively filled with grout on the anchor pieces and sand over the active zone, in order not to perturb the strain field in the clay core and to guarantee good deformation transfer from the clay core to each deformation sensor making a part of the extensometer.
Nombre de capteurs: 
10
Résultats: 
The results of the monitoring are not disclosed.
Figure 1: View of Canales Dam
Figure 2: A 50 m long multipoint extensometer ready for the installation in the borehole
Figure 3: Schema of the installation procedure
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