Environmental Engineering Reference
In-Depth Information
Figure 15.26.
Foundation treatment and plinth design San Juana Dam (Marulanda and Pinto, 2000).
The plinth is constructed using concrete with strength of 21 MPa at 28 days using metal
or timber forms. This is followed by grouting of the foundation either downstage or
upstage.
15.4.2
River diversion
Generally the river is diverted by tunnels but many projects have allowed for overtopping
of the rockfill embankments provided protection measures to prevent unravelling of the
downstream face are taken. These measures include steel reinforcement of the rockfill and
gabions anchored into the rockfill. In large rivers a diversion strategy is chosen to opti-
mize the tunnel size incorporating a “priority” section which has a low probability of
being overtopped (
Figure 15.27
).
15.4.3
Embankment construction
All types of granular fills have been used in CFRDs, selected as appropriate for the differ-
ent zones. Quarried high strength rock such as granite or basalt has been used in all zones.
Lower strength rock is usually placed in the central or downstream part of the dam.
Compacted alluvial gravel has proved to be an excellent rockfill with a high modulus. The
