Indian National Committee on Large Dams. Design and Construction Features of Selected Dams in India
Подождите немного. Документ загружается.
r06
PHOTO
5 :
Non-overflow
blocks
at
the left
flank
being
raised
by
lifting
stone
and
mortar
by
Washington
and
Clyde
cranes.
PHoTo
6
: Scaffolding
erected
on the
front
face of dam
over
punts
floating
in
the
reservoir
upstream-
PHOTO
7
:
Work
on the
non-overfiow
blocks
proglessing
monotower
cranes
in sitle by
side
blocks'
simultaneously
with
timber
scaffolding
and
bamboo
walk
way
erected
in
a number
of
flights
suP,
ported
by a
num6er.of
vertical.
horizontal
and
inclined
hemberi of
wooden
ballies forming
a
rigid
frame-
on
the
left
side,
with top at
*83.21
m
(+273.00
ft)
and
cranes
erected
on
rails
on this
platform. Mortar
the
usual
method
of
lifting
by
manual
labour
over
scaffolding
was
resorted
to.
An
innovation
made
for
reducing
the
lift
was
to
supply
mortar from
the
approach
space
to
the
top of
dam
for
-ltlling
materials
*ras
erection of
iteel tubular
scaffolding
As
the
lift
increased still further,
i.e.,
above
1-
115.83
m
(+380.00
ft)
level, the utilization
of manual
labour
became
uneconomical
and
impracticable
and
hence
trestle
bridge
with
monotower
cranes
were
employed.
The maximum
flood
discharge
in
the river
is
<if the
order of
33,980 cumecs
(12
lakh
cusecs)
and
diversion
of flood flows
through
tunnels
and
other
*#s+*..4t'
t07
means
is
not
fcasibre.
Erection
of a
high
erevated
steel
rrestle
to
cover
nearly
ql0
ry
(2.0d0
fti
jengtf,
requires
time.
ard
rar-qe quintity
or
rteet.--
Spun
it;
conve)'ance
of
materials
from
flank
to
flank-
of
the
river
also
is
.
large.
Hence.
n*.J
torn.i'l.un.,
,r,itt
low
level
trestle.
b-ridge
is rhe
most
suitabre
Gchnique
for
raising
the
dam
ii
trre
secono
rtuge
oi.tnrtruction
above
+
il5.g3
nr
(+
3g0.00
ft)
"I.u.t."'ir,.
tift
involved
in
rhis
1.ug. -,_,
from
40
to
llb
n;
(130
to
360
fr).
Another
Blaw
Knox
batchin_e'pi";
with
a
!1t1e^ry 9f
mixers
\
/as
erected
uT
'+
ijs.oz
m
(+420.00
ft)
level
in
this
rrestle
stage.
A 7.32
m
e4
ft)
yiOq
roadrvay
\\'as
formed
at
+
lze.oZ;
(j
420.00
ft)
level.
A
Masonry
ledge
was
fornred
on
the
dolvnstream
face
of
thl
non-"ou..flow
au---r..tion
for
the
roadway.
In
the
spillrvay
dam,
"
;;;l
uifo_e.
*itn
sreel
trestle
columns
bt
1g-29
m'(60
ft)
nei-eht
and
:gull.g
by_
steet
girders
of 12.19
to
iZ.iA'^
(40
to
75
ft)
Iength
rvas
eiected
which
could
be
removed
or
cut
arvay
qfter
the
dam
was
completed.
A-
portion
of
ihe.
spilhvay
dam was
not
covered
*,ith
the
lr;^tl]:_qridge
to
allowfor
peak
florvs
O"ring
floods.
r i
numDers
of
monotower
cranes
designed
6y
Messrs
Fried
Rich
Kocks
of
west
Germany
were
erected
on
the
_partially
built
dam
at 73.15
^
fiiO-f,i'-..nrr.r.
r
nese
cranes
can
handle
a
load.of
g,l3
tonnes (g
tons)
at
a
radius
of 28.2
r-(9?
fr
6 in.) with
a
.upi.ltv
to
rift
yp
1o
gl
m.(200
ft)
height.
B,v
means
of
a
self-erect-
::i,::]1..'t
tlrg
jib
of
rhe
crane
can
be
lifted
to
any
requrred.
her_sht
*,ithout
dismantling
any part
of
thl
crane.
As
these
cranes
are
fixed
ones,
the'
portion
of
the
structure
rihich
ray
in
the main
a"---r"Ir^turried
and
the
balance
o'iry
retrieved.
The
u.luat
.v.r.
time
of
operation
was
worked
out
to
g
minut.i-
H.n.,
each
crane
could
tackre
about
56.90
tono.r--ii6
tons)
per
hour.
either
of morra.r
or
rubble.
d;;"i;g
thai
tlre
mortar
rveishs
about
2.7g
tonnes/cu
m
(g
tons/
100
cu
ft),
the
crane
could r,r,
iis.5g
.;_"(5,300
.u
ft)
of
nrortar
in
a
period
of
8 hours,
ri,hich
would
be
sulhcient
to
build
about
340
cu
m
(12,000
cu ft)
of
nlasonr-v.
constructron
of
masonry,
,t.e.,
placing
ltlortar
and
fixing
stone.
was
done
'throughout
i;
.iiltug.,
of
consrruction
by
means
of
man-ual
faUoui
lnly.
The
rate
of
consrrucrion
was
zo
labou.;-i;;
ifout
s.so
cu
m (300
crr
ft)
of
masonry
per
du,u
le
average
daily
outturn
of
reriod
of
construction
was
cu
m
(2,55,700
cu
fr).
The
e
and
sand
for
the
average
L (1,00,000
cu
ft)
of
,ur6_
:the
daily
requirements
of
abo ut
r,
400 rvorked
d"ir;?;Ii1;",t
IIl",t'.tl;13:hr:l
the
first
srage
work
on
ihe
ouqt
roi
*ii.r,-
the^'
rubbre
rarries,
the quarrv
labour
ers
and
compressed
air
for
method
of
hand
drills.
Bur.
as
submerged
and
distanf
Bandlakarva
were
tackled
,
the
dam, p,leumatic
drills
wever,
employed.
108
PHOTO
8
:
A
general
rierv
of the
dant in
monoton'er cranes
and
trestle
progress
n'ith timber
scaffolding in
some blocks and nith
bridge
in
some
other
blocks.
until
the
gallery
concrete
was iaid and the
masonry
was
raised
evenly
over
the entire
block.
Concrete
around
the
metal sealing
strips
at the
vertical contrac-
from 0.01
to
0.035
cu
m
(3/8
to
3
cu
ft).
Stones
for
face work
\\'ere
29.21cm
(11$
in.)
in
height
and
38'I
cnr
(15
in.) in depth.
50
percent
of these
face
stones
were
more
than
O.Ot
m
(2
f0
long
and the
headers
\\'ere 0.76 m
(2.5
ft)
deep.
It took
xbout
l0
years
to
piace the
stupendous
quantity of 5.63
miliion
cu
m
(199
miiiion
cu
ft)
.of
rrruronry
and
concrete
in the
dam
(Figure 10),
_
Paucit.v
of fundi
\\'as one
of the
t'actors
that
contributed
to such
faster
than
masonry
dams derivin-s the
benefits eariier.
specially
because the
construction
rvork
on
concrete
dams
goes
round
the
clock,
whereas masonry
is laid
one
layer
per
day during
day
time onh,.
This
miscon-
ception
was
disproved
with the
construction
of
Nagarjunasagar
Dam,
where,
on an
average.
3,540
cu
rn
(1,25,000
cu ft) of
masonry was laid
in a single
shift
of
8 hours
per
da1', regularly for
6
da1's
in
a lveek.
s'itir
the
peak
outturn
figure
reaching
lr
ice the
magni-
tude. Tlie
pace
of
construction
of masonrt'
datn
need
not
lag
behind
that of concrete dam.
Construction
in masonry can
be
as
speedy
as
in
concrete.
provided
suitable construction
technique
and
programming
are
devised.
On
Nagarjunasa,qar
Dam.
rubble
was
conveyed
to the top
of the
blocks in
the
night
time
and manufacture
and
convelrance
of
mortar
and
laying of
masonrl'I done
in
the
day
time in
order
to
speed
up the
rvork.
This
was
again
in
spite
o1'the
fact
that even
the convevance
of
rubble
and
mortar
\\'as
simultaneousil'
to reap early
benefits
from
tlie
project.
Masonry
construction
is aiso
cheaper
leading
to
plenty of
emplo)'ment
potential for
labour
inasmucb
109
PHOTO
9 :
.{nother
vierv
of thc
partly
comp)eted dam
in the spillnay blocks
kept
high and nith
as operations
such
as
breaking stone
to
suitable sized
aggregate
and
erection
of
form
work
and shutterin_e,
etc.,
involved
in
the
case of concrete,
can be
avoided.
Conveyance
of
stone
and send from
quarries
to dam-
site
by
lorries
by
manual
loading
and
unloading
and
lifting
stone
and
mortar to
top of
danr
by
head loads
over
scaffolding
in
the
lirst
sta,ee
of
construction
of the
dam
are
the other factors
that led
to abundant
employ-
ment
of
labour
and economy
in
cost.
The
rvinding
scaffolding
over rvhich
thousands
of
labour
carried
enormous
blocks
of
cutrock
and
other construction
materials
like
rnortar
and
concrete over
long
distances
and
great
hei-eht
was
a
stirring spectacle
harking
back
to
the
age-old days
of the
great
temples
of
South
India
and ancient
Pyrarnids of
Egypl.
Nagarjunasagar
Project
ranks
first
in
man
power
urilization among
the
modern gigantic
projects
of
its
kind
in rhe whole
rvorld.
Another
outstanding
feature of
this
gigantic
dam is
that
the
entire
ccnstruction
right
from
the
i,nvestigation
stage
was
nranned by the
Ind
ian
engineers.
tt
is
a
monum:irt
to
the
indigeilous
technical
-skill
and talent.
This
marnillorh
project
constitutes
the
pride
of tndia
and
the
hope
of Andhra
Pradesh.
The
permissible
leakage
through
the
masonry
at
arty
elevation
is
0.05
and
0.245
iitres/minisq
m
(0.01
and
0.05
gpm/sq
ft)
of
the surface area in
the
front
rmpervious
zone
and
the
rear zone respectively,
at a
pressure
equal
to
1i times the
maximum
head
of
i10
in
floods
nith
nronotorver
cranes
and
trestle
bridge
overfow
oler
the other
spilhvay
blocks
kept low.
water
at
that
elevation.
Permeabiiity
tests
were
conducted in blocks
22
to
64
through holes drilled
in masonry.
On
an average,
three
holes
were
drilled
per
block in
trvo
rows,
two
in
the upstream row at
about
2.44
m
(8
ft) lrom
the
front face
of
dam and one
in the downstream row
at
about
27.43
m
(90
ft) down-
siream of
the
axis of
dam.
Out
of a
total of 127 holes
drilled
and tested.
percolation
in
56 holes
was nil
and,
in theother remaining
holes,
it varied
from 0.006
to
to
I4.68
litres/min/sq
m
(0.0012
to
3.00
gpm,lsq
ft)
at a
pressure
of
l.l6
to 2.46
kglcm2
(25
to 35
p.s.i.).
When
the
holes
rvith
excessive
seepage
were
_e,routed,
the
grout
intake was
very little,
the maximum
in
any
hole
grouted
being
only
7.75
bags. Even after comple-
tion
of
the
dam
and
building
up
the reservoir to the
M W.L., the seepage
collected
in the first
1'ear
of
fiiling,
i.e,
in
the
year
1974,
was
400
litres/min.
(88
Spm),
as
against the
p:rrnissible
seepage
of 56,370
litres/min
(12,400
gpm)
at
M.W.L.
Even this
quantum
of
seepage was
on
the
decrease
year
by
year
and,
in
tire
year
197I
,
it
carne
down
to
t Sg.
Z
iitres/min.
(4l.1gpm).
Thus,
the
seeprge
through this
nlasonry
dam
is
found to
be
not
only
far less than
rvirat
can
be
safely
alloweC but aiso much
Iess
than
rvhat
can be
expected
even
in
concrete
dams.
By using
face
storte
rvork
rvith
coursed rubble
masonry
in
rich cement
mcrtar
rvith
surkhi adrnixture
on the
front
face
of
the
dam, considerable
rvatertightness
is
achieved
in masonry
rvhen
compared
to concrete,
with the
result
that
masonry
dams
are
less
perileable
than concrete
datls.
PHOTO
l0
:
The dam
under construction during the
nights under
flood lights.
PHOTO
11
:
An aerial
rierv
of
the
completed
dam tt'itlt
overflow.
r11
9.3
Construction
of
Earth
Dam
(l)
Lrrr
ElnrH
Deu
pgr.ce.nt
of
clay was
spread
to
a
thickness
of lS.Z4
cm
(6
in.)
by
manual
labour
and
consolidated
eirher
by
manual
labour
or
with
a
D6
tractor.
This
process
was
continued
till
all the undulations
in
the
foundation
rock
were
covered
and
levelled.
Otherwise
movement
of
heavy
machinery
for consolidation
would
disturb
the
foundation
strata.
In
the semi-pervious
zone,
however,
so much
treatment of
foundation
surface
was
not
necessary
and
hence
not
given.
After
the
initial
layers were laid,
the
embankment
cornpact gravelly
soils. Each
layer
thus laid
was
compacted
to
98
percent
of
proctor's
density.
In
order
to attain
this compaction,
about
35
passes
were
given
to
both
impervious
-and
semi-pervious soils.
During
the
early
years
of construction
when
earth
moving
machinery
was
available,
shovel-cum-dumper
and
dozer-cum-scrapper
combinations were used for
the conveyance
of
borrow
soils at a
lead
of
6.4 km
(4
miles).
Nearly
6,79,680
cu
m
(24
million
cu
ft)
of
borrow
soils
were
done
with
this machinery. Subse-
quently,
when
some
of the
machinery
was
diverted
to
other
projects,
5.08 tonnes
(5
tons)
lorries were
engaged
for
conveyance
at leads
ranging from
6.4 to
12.8
km
(4
to
8
miles).
About
7,08,000 cu
m
(25
million
cu ft)
of borrorv
earth was
conveyed
by lorries. The
peak
outturn
achieved
with the help of
lorries
was
56,640 cu
m
(2
million cu
ft)
by
engaging
about 120
lorries.
Rockfills
on
upstream-and
do*nstream
'sides
wffe
,
constructed
with
quartzite
stone
available
nearby
and
rt2
I0. Comple-tioo.-gf
D"q,
Initial
Reservoir
Filling
and
Operation
(Photos
8
to
ll)
gradual
stages at
the rate
of
about
1.52m
(5
ft)
per
fortniglt.
In the.follorving
_year
1975,
the
gates
were
tested for operation.
Free
flow
was
allowed
over
the
spillway
_by_keeping
all
the
gates
open
at
the commence-
ment of the flood
season
and
-reservoir
level
not
exceeding
+173.74
m
(-FSZO
ft)
was
maintained
throughout the
flood
season.
When
the
inflow
started
decreasing
in
the
month
of
September,
the reservoir
was-bujlt
up
t_o
a level
of
+
176.78
m
(+580
ft),
raising
gradually
ar
the
late-of
0.30 m
(l
ft)
in
4g hours.
Th;
reservoir
was.
further
impounded
to
the FRL
of
10.3 The
following
rules
were
framed
and
followed
for
operation
of
the
reservoir
with crest
gates.
(f)
Releases
for
the reservoir
into
the river
down-
stream
shall
be
done
through
the chute
sluices
till the
reservoir
level
rises
to
*
167.34 m
+5+?
ft), when
the
spillway
can discharge
"
453.12 cumecs
(16,000
cusecs).
(ri
)
(iiil
(tv)
(')
The
chute
sluices
shall be
closed
when the
reservoir
level rises
above
+ 167.34 m
(+
54e ft).
All
the
crest
gates
shall
be kept
open
at
the
be-einning
of the
flood
season.
During
the
preceding
period
of flood
season,
all
the
crest
gates
may
be
closed
or
operated,
as
the
case may be, at
the
appropriate
time
for regulation
of
rvaters
from
the
reservoir,
taking
into
consideration
the inflow
pattern
and
the
quantum
of
water
to
be
impounded
in
the reservoir.
The
crest
gates
shall be
operated
in
such
a way
as
to
keep
a uniform
opening
for all
or
most
of
the
spillway
vents to the
extent
possible.
(vi)
The
crest
_q.ates
shall
not
be
operated for
a
partial
opening
of
1.52 m
(5
ft)
and below,
(viii)
I-f
any
v_ortex
formation
is
observed
upstream
due
to differential
gate
openings in
ddjacent
vents,
the
gatg
openings
ihall
be
regulated
suitably
to
avoid
the
same.
(ix)
If flow
through-
end
spillway
vent hits
the
training.
ryell,
the
gatebpenings
shall
be
re-eu-
lated
suitably
to
avoid
the
same.
^lppendix-I
Salient Features
of Nagarjunasagar
Dam
Location
2.4
km
(l+
miles) dorvnstream of Nandikonda
village.
Miryalaguda
Taluk,
Nalgonda
District, Andhra
Pradesh.
Latitude 16"
34'23"
N.
Longitud
e
T9"
18'
47" E.
Hydrology
catchrnenr
area at
I
215;
1g5
sq km
-
the
damsite
J 1Sf
,bt:
sq
rniles)
l
i
,.t
cumecs
(100
cusecs)
l
58,340
cumecs
(20.60
lakhs
J
cusecs)
I
45,310
cumecs
(16.00
lakhs
J
cusecs)
(10.61
lakhs
+
179.83
m
(+
590.00 ft).
+
181.05 m
(+
594.00
ft).
+
r21.92 m
(+
400.00
ft).
Mean annual rain-
I
fall in
the catch-
|
89
cm
(35
in.)
ment
)
lffil
,l,?'::'Jl#.
]o
',u *
Maximum
observed
flood
at
Vijaya;
wada
anicut
Minimum
dry
weather
flow
1,0O0-year
design
flood
Routed flood
Reseryoir
Full reservoir level
Max.
water-level
Dead storage level
')
F
30,050
cumecs
)
cusecs)
ham
(34.34
M
acre-ft)
113
Masonry
Dam
Length
of
spillway
dam
Length
of
non-overflorv
dam
Total
length
of
masonry dam
Maximum
heisht
of
dam
above
deepest
f5undation
Height
above
average river
bed
Top
width
of
dam'
Max.
base
width
of dam
Overall
width
of roadwav
on
top
Deepest
foundation
level
1
Average
river
bed
level
Spillway
crest
level
Top
of
crest
gates
Top of
dam
Invert
level
of
flip
bucket
Crest
gates
Chute sluices
47r
m
(1545
ft)
979
m
(3211ft)
1450
m
(4756
ft)
124.66
m
(409
ft)
rc9.7
m
(360
ft)
8.53
m
(28
ft)
97.s4
m
(320
ft)
9.30
m
(30
ft
6
in.)
+s9.74
m
(+196
ft)
+74.68
m
(*245
ft)
*166.42
m
(
*5a6
ft)
*
179.83 m
(*
590 ft)
*
184.40 m
(+
6os f0
+73.15
m
(+240
ft)
26
Nos. of
size
13.72 m x
13.41
m
(45
ft
x
44 ft)
2
vents of size
3.05
m
x
7.62m
(10
ft
x
25
ft) with
sill at
+137.16
m
(*
450 ft)
Penstocks
Ri-eht
canal head
sluice
Power
sluices
Earth
Dam
Length
of
left earth
dam
Length
of right earth
dam
Total
length
Maxirnum
height
Top
width
Top
level
Quantities
Masonry
-
Concrete
Total
quantity
for
)
masonry
dam
J
Cement
Steel
Earth
work for earth
dam
Estimated
Cost
Min.
drawdowir
level
+
155.45 m
(+
510.00
ft).
Waterspread
area
285
sq
km
(110
sq miles),
Gross
storage
capa-'1.
11.56
TMCM
(405
TMCF
city
at
FRL
r
+izs.slml+ sgo r,l
j
or 9'37
MAF)
I,ive
storage
capa-
I
city
above
MDDL
!
5.56
TMCM
(195
TMCF
or
of+155.45m
,
4.51
MAF)
(+
slO
ft)
j
:
)
l
rt4
8
Nos.
of 4.88
m
(16
ft)
diameter with
centre
line
El. 123.4
m
(405
ft)
9
vcnts
of
size
3.05m
x 4.57 m
(10
ft
x 15
ft) rvith
sill
at El.
+
149.05
m
(+489
ft)
3 Nos.
of size
4.57mx11.58rn
(15
ft x
38 ft) with
sill
at El.
+
146 m
(+
479 rt)
2,560
m
(8,400
lt)
853 m
(2,800
fr)
3,413
m
(11,200
ft)
25.9
m
(85
ftt
9.30 m
(30
ft 6
in.)
*
185.93
m
(+610
ft)
4.842
M
cu
m
(
l7l
M
cu
ft)
0.793
M
cu
m
(28
M
cu ft)
5.635
M
cu
m
(199
M
cu
ft)
11.22 lakh tonnes
(11
lakh
tons)
61,200
tonnes
(60,000
tons)
2,29
M cu
m
(81
M cu ft)
Rs.
85.8
crores
Append,ix-II
Selient
Features of
Nagarjunasagrr
Cuals
Jawahar
Canal
(Right
Main Canal)
Lal
Bahadur
Canal
(Left
Main
Canal)
(l)
Length of nain
canal
203
kry1394
kn
(126
mites/ 178
km/300 km
(
l1 I
miles/
-
(phaselultimat
e)
245 miles)
187
miles)
(2)
Maxinum bed
width
73.51
n176.25
m
28.96 m
(95
ft)
'
'
(phase/ultimatc)
(241
frl250 ft)
(3)
Depth
of flow
(hesd
rcach) 3.60
m/4.575
m 6.40 ml6.7l
m
.
(phase/ultimate)
(11.8
fvl5.0
ft)
(21.0
fu22.0
f0
(4)
Maximum
discharge
312 cumecs/595
cumecs 312 cumecs/425
cumecs
-
(phasc/ultim4te)
(11,000
cusecs/21,000
cusecs)
(11,000
cusecs/15.000 cusecs)
(5)
Hcad
regulator :
(a)
Sill level
+
149.05
m
(489.00
ft)
+
149.05 m
(489.00
ft)
(b)
Ventway
9
vents
of 3.05 m
x 4.575
m
3
vents of 3.05
mx 7.62 m
(10
ft x 15 f0 each
(10
ft x 25 ft)
eech
(6)
Lcn8th
of branchcs
and
5,342
km
(3,320
miles)
7J72 km
(4'830
niles)
distributaries
(7)
Lcngth of
field channels
14,480 kn
(9,0@
milos)
9,655 kn
(6,000
miles)
(8)
Nct iniqablc
arca
4.?5
lalh ha/7.605
lakh
ha 3.97
lath ha/4.45 lakh ha
'-'
ip6t"lo-tti-"61
G1.74
fakh
dcrcs1l8.78
lakh
acres)
(8.80
lakh acies/11.00
lakh acrcs)
(9)
Man
power
45,0@
34'000
(lO)
Estimated cost
Rs. 211.8
brores
Rs. 201.4 crores
115
s,
.
a'+a--ll