GLOBO{bICA
DAM
The Globoilica dam was
constructed on
the river
Crni
Drim i'n Macedonia. This dam
Greates
part
of the head for
the
.remote'
insta'llations of
the Globodica
power
station.
The
power plant
is
installed
on
the discharge of 50 m3/s,
and
rated
power
of 42
MW.
The bedrock in the dam site
area
belongs to the Tertiary
and Ouaternary
formations
and
consists of
stratified
li-
mestones. On
the left
slqpe
of the dam
profile,
stretches
a
zone
of
red hornstiones
and
clayey
sichists.
The dam siter
underwent con-
si.derable tectonic rnovement
so that systems of
frissures
and cracks
?,re
h,ighly
pro-
nounceci
as
'well
as
the
rock
mass
permeability.
The thickner;s
of
the river
deposit
on the dam site area
is approximately
12
m.
The
dam is of the
rockfill
ty-
pe
with
a
thick
clay core
and wide transition zones.
The dam was
founded
on al-
luvial deposits. lmpermeabili-
ty
of alluvial deposits was
obtained by a thick
grout
curtain executed from
three
grouting galleries
below the
clay core. Tlre
grout
curtain
consists of 18 rows
of bore-
holes
whir;h
were
grouted
with
thyxotropic
arouting
mi-
xes.
The gr,out
curtain was
exe-
cuted
inr three rows. The
high
permeabilitll
of the
rock
rea-
ches
as
tar
as some hun-
dreds
of meters
deep but the
grout
curtain
was
constructed
with
a maximum depth
of
74
m. The
measureri water
los-
ses, after
tlre
hasin
had
been
filled
up,
showed
that larger
groutin,g
worl<s would
not
have
been economically
ju-
stifiable.
The
diversion of water
du-
r.ing
construction was
per-
formed
by a cofferd'am
22
m
high
arrd
b11
a diversion
tun-
nel.
Morning
glory
sp,irllway
of 1,10t1
m37/s capacity
is con-
nected
to
lthe
outlet
tunnel.
This
turnnel drains into
the
chute which ends
with a ski
jump.
The
radius
of the
spill-
way
at ther cr'est is
36 m,
while the radius
of the
tun-
nel
is
19
m.
By
observations measure-
ments
of clamr displacement
have
been encompassed,
measur,ements
o,f
the core
setting
and of
tpore
pressures
in
the core, recording
of the
ground
water
tables and spe-
cial
observatiorns of
percola-
tions and
pressures
in
the
grout
curtain
in
alluvium
to-
getlher
with
periodical
che-
mical water
ilnalyses.
Mea-
surrgments harre
shown that
the dann behaviour is
sati-
sfying.
In November
1967
the
dam
sunyivedl
an
earthquake
of
about 6.5o MCS
without
un-
dsl'going
any
damages.
1. Dam
2. Cofferdam
3.
Spillway
4.
Chute
with
ski
jurnp
5.
Diversion
tunnel
-
bottom
outlet
6.
Headrace
'trunnel
7. Gatehouse
8.
Grouting
gallery
-
grout
curtain
I Barrage
2. Batardeau
3, D6versoir
4.
Coursier
avec saut
de
5.
Galerie
der
d6rivation
6. Galerie
d'amen6e
7. Chambre
des vannes
8. Gal,er:ie
d'injection
i
GROUND
PLAN
OF THE
SITUA'IIION
DU BARRAGE
vidange
de
fond
_l
l
l
l
_l
l
l
I
I
I
I
1
1
I
I
1
L
I
J-
t
114