Environmental Engineering Reference
In-Depth Information
socorridos pumping station and water storage tunnel
at Madeira island
J.M. Brito, s.P.P. Rosa & J. santos
Cenorgeo, Engenharia Geotécnica, Lda., Lisboa, Portugal
J.a. sousa & a. Pedro
FCTUC, Coimbra, Portugal
aBsTRacT: The socorridos pumping station and water storage tunnel are located at Madeira island,
Portugal, and are part of a system conceived to reutilize the water flow from the socorridos hydroelectric
plant. This facility includes an underground cavern with 26 m high, 12 m wide and 44 m length, and a
tunnel 1250 m long with a storage capacity of 40,000 m
3
. The rock mass at the site is of volcanic origin
with most of the excavation performed in a mass of volcanic breccia and basalts but with consolidated
alluvia recent deposits located in the roof arch of the cavern. a description of the main characteristics of
the project is presented and the results predicted by the design are compared with the values given by the
instrumentation.
1
inTRoDUcTion
The multi-purpose hydraulic system of socorridos,
located at Madeira island, is composed of a vast
network of reservoirs, tunnels and channels with
the purpose of producing electric energy and sup-
plying water to the region.
The socorridos pumping station and water stor-
age tunnel belongs to this system, which comprises
storage capacity, which receives, during the day,
the turbined water of socorridos's hydroelectric
power plant; ii) an underground pumping station
including four vertical powerful pumps that, dur-
ing low-consumption periods, mainly during the
night, feed, in a period of six hours, the water back
to a reservoir located 460 m above, in order to be
reutilized by the turbines of the existent hydroelec-
tric plant; iii) an auxiliary tunnel (with direct access
to the water storage tunnel and to the lower half
section of the pumping station; iv) a water gallery
connecting the hydroelectric plant to the pumping
station; and a sand discharge gallery associated
with the sand extraction system conceived.
Due to its high complexity, particular care was
assigned to the design and construction of the cav-
ern for the pumping station (
Fig. 2
).
The main concerns were the geological and
geotechnical characterization of the rock mass,
the complete numerical modelling of the con-
struction process and the observation scheme to
be adopted during the execution of the relevant
works (cenorgeo, 2005).
Figure 1.
General plant of the hydroelectric system.
a)
b)
Figure 2. a) General view of the superior half section
of socorridos pumping station and auxiliary tunnel; b)
interior view of the pumping station.
