Japanese National Committee on Large Dams. Dams in Japan, No. 10
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l.
Introduction
The Tenry
River
rises from
Lake
Suwa
in Nagano-ken
and flows down
south through
the central
part
of Honshu
Island
and
empties
into
the
Pacific
ocean at
the Enshun;da
in
Shizuoka-ken,
and
is one
of thJ
three
l".g"rt'.;;;
rivers
of
Japan.
Sakuma
Dam
was
built
on the
middle
stretch
of the
TenryuRiver.
."^,,,11^1":l91tl:L:l
the
sakuma
project
had been
set
up from long
before,
but
because
of
the insufficient
transportation
raclllues
lor construction,
floods
of as
much
as 7,000mr/sec,
and excavation
of
river-bed
deposits
of as
thick
as 25m,
it was
expected
there
would
be extreme difficulties
€ven with
the engineering
technology
of Japan
at
that time,
and development
had
been
deferred.
However,
due to
extreme power
shortage
after world
wJi
II it was
u"irg
a"i";o"o
that
develop-
ment
of
sakuma
Dam
be carried
out as
early as
possible.
Therefore,
the Electric
po*.r
oJuetoprnent
co.,
Ltd. was
established
to
be assigned
the responsibility
for
deveiopment
on the
Sakuma
site.
.
work.was
staned
in
April
1953, and-
by adopting
iechnologies
from abroad
and
first
mechanizing
work
in Japan,
it was
made
Possible
to
start
operation
in only
3
years,
ind a
great
contribution
was
made to the
recovery
o-f
Japanese
eco'omy.
2.
Topography
and
Geology
- .
The vicinity
of the
damsite
is a steep gorge.
Overburden is
generally
thin with practically
none
at the
left bank
and
thickness
of 1
to 2m
above
mid-height
on
thJ right-bank.
The alluvium
at
the dve;
bed is
ispecially
thick
on the
dght
abutment,
being
as
thick
as 25m
at most.
The
foundation
rock of the dam
is composed
mainly
of biotite granite
which
is
generally
hard
and sound.
-The
granite
at the
right
bank is
completety
decomposed
at sha'ilow
depth.
Thi faults
are
all of
smail
scale, but
those
at
the
uPper part
of
the right
abutment
and
the downitream part
of the
apron
have sheared
zones
containing
clay
of 2m
wide,
and
weathering
of
the former
rs extreme.
3 .
Construction
3-1.
Matedals
The
1'5
mitlion
mr of concrete
aggregates
were
manufactured
from
river
bed deposit
availabte
at
a site approxrmately
3km
downstream
from
the
dam site
aia
crushing plant (700Vhr)
provided
in
the vicinity
of
,rr"
gruJ
pi,l
una *"r"
t.unr-
ported
to
a batching
Plant
at the
left bank
immediately
downstream
of the dam
uy a
uett
convEyer
tiri"'Lt
uppro*i-ut"ty
2km.
Cement
was
traniported
by rail
to Chubu
Tenr)'u
station
approximately
3.5km downstream
of
the
dam,
from where
a
concrete-paved
c€medt
transDort
road
of approximatety
2.5km was built
to'the
batching
plant,
una
""rrr"rrt
was hauled
by
20-t
trailer
trucks-
3-2.
Concrete
Placement
- ^ - -Congrete
was placed
by
two 25t tmvelling
cable
cranes using
6m3 buckets.
Concrete placement
was
started in
January
1955
and
completed
in 20
months,
in Augusi
1956.
Placing
wis done
in
1.5m lifts
and
in" auity
"nJ
montnty
maximum
Placement
volumes
were
approximately
sJoo
and
104,000m1
respectively.
The minimum
unit
c;ment
content was
l60kg/
mr-
3-3
.
Construction
Joints
spacing
of 15m
were
made standard
for
transve$e
joints
and 45m
for
longitudinal
joints.
construction
was
by the
block
method
up
to
EL.
180m, while
above
EL.
1E0m where
bottom
widths
iould
be'smaller,
l"rui
roi"r construction
joints
were
eliminated.
ouxlliory- Dom
TYPICAL CROSS
SECTION
*
3_-5.
Foundation
Treatment
kg/cm',
and
the
total
length
was
approximately
6,3000m.
4.
Sedimentation
5.
Power
Generating
Facilities
re82).
H.
Cooling
Pipe
cooling
was
performed
to
prevent
cracking
due
to
heat of
hydration
of cement,
and
precooling
was
also
used
to
hold
down placing
temperature
to 13"C
or under.
ring
hot weather
in
summer
The
upstream
side
curtain grouting
was performed
after completion
of consolidation
grou
at
maximum
and
with
grouting
pressures
between
5 and 35kg/cm,.
Curtain grouting
from
tt
forl_ed
with
depths
of holes
30m
and grouting
pressure
of 30kg/cm'.
The
total
length
of
16,000m.
The points
of consolidation
grouting
were
in a
range of
central
part
,
20m
on
both
upstrr
the
dam
axis,
with
staggered
holes
of 2.0m
spacings
and
hole depthi
of
0.8m.
Grouting
pre
The
sediment
at
the
upstream part
of
Sakuma
Reservoir
is of
good
gradation
with
the g
sand
having
high
suitability
as fine
aggregate
for
concrete.
Howevir,
roads
in
the
surroundi
and
lacking
in
transport
capacity,
olso it
is
difficult
to
broaden
the road,
the hydraulic
adopted,
after
comparable
studies
with
the
alternatives
of ropeway
and belt
conveyor.
Since
major
tectonic
lines
(Median
Dislocation)
intersect within
the
basin,
the geological
{onditions
in the
area
are
ex-
tremely
-unfaYorable.
During the
rainy
season in
June and the typhoon
season in
Septeirber,
since
there are
often to,'en-
tial localized
rainstorms
of more than
200mm
daily, erosion ana
iiiding of
mountaint;nds
ur"
{"-"r..
Because
or tnis,
all
of the
reservoirs
on
the Tenryu
River are
troubled
by rapid accumulation
of sediment.
Sehiment
in
Sakuma
Reservoir
reached
a volume
of
73 million
m3
corresponding
to
23Vo of
the
total
storage
capaclty
in
the
1956
to
1980.
of
a
mere 24
years
from
ng
using
hole depths
of
66m
inspection
gallery
was per-
grouting
was
approximately
am
and
downstream
sides of
ures
were
between
3 and
5
ter
part
good-quality
quartz
of the
reservoir
are
narrow
of
the
sediment
was
Rio
de
Janeiro.
1982.
manv
ln
order
to
economically
perform
slurry
transport,
as reported
under
Q54,
R. 4,
ICOLD
kinds
of
pipe
tests
have
been
carried
out
in
the
Sakuma
area.
A
maximum
306.0m3/sec
of water
is
conducted
from
an intake
tower
of
8.0m diameter
gates
of
width
of
5.0m
and
height
of
8.5m) at
the left-bank
of the dam
through
two
circular
meters
of
7.0m
and
lengths
of 1,180.6m.
These
funnels
bifurcated
at
surge
tanks
to
pass
thro
4.8
to
3.8m
and
lengths
of
147.1m.
Utilizing
the effective
head
of 133.5;,
350Mw
bf po*".
al
Francis
turbines
and
generators
at
a
semi-underground powerhouse
approximately
t.)tm
a<
water
discharged
from
the
station
is directly
taken
to the intake
of
Sakuma
No.
2 Power
Stati
nd
35.0m
high
(2
caterpillar
tunnels
of
inside
dia-
penstocks
of diameters
of
generated
with
four
vertic-
ream
of the
dam.
The
(32MW.
commence
ment
UPSTRE.A,M
VIEW
87
a
i
28.
SAMETJRA
DAM
Location
Nearest
City
.
River
Purpose
Catchment
area
Mean
annual
discharge
Years
of
construction
.
Type
Foundation
Height
Crest
length
Volume
Spillway
Type
Type
and
number
of
gate
.
Maximum
discharge
capacity
Reservoir
Gross
capacity
Effective
capacity
Area
Drawdown
range
Owner
Engineering
by
Construction
by
t
Tosa-cho,
Tosa-gun,
Kochi-ken
Kochi-shi
Yoshino
Flood
control, Maintenance
of normal
function
of the
river
water,
Irriga-
tion, Water
supply and
Hydroelectric
4I7km'z
33m3/s
1967-1975
Gravity
Graphite
schist
106m
400m
1,200,000m,
Controlled
Crest fixed roller
sate
X
6
6.000m3/s
316
X
106m3
289X
10qn3
7.5km'?
68m
Water Resources
Development
Public
Corporation
Ditto
Hazama-Gumi
Co.. Ltd.
\
88
TYPICAL
CROSS SECTION
o-lP
4-1lP-P'
Sameura
Dam,
which is located
on the middle
part
of the Shikoku Island,
has
the largest
gross
storage capacity
in
the
multipurpose
dams
in
present
Japan.
And this dam contributes
much to
both in flood
controiand
wateiutiliiation
of
the
Shikoku
Island
as
the capital facility
of the
Yoshino River Development
project.
1.
Geology
At
the
surroundings
of the dam
site, crystalline
schist
which
is
called
Sanbagawa
zone
is widely
distributed-
89
Sanbagawa
crystalline
schist zone
is between
the edges
of Gross Median
Split on
the north
side and
Mikabu
Split on the
south
side,
and
forms
the main parts
of Shikoku
mountain
range.
The
foundation
of
the dam is mainly
composed
of
grap-hitic
and
siliceous
schists.
Their compressive
strengths
are
good
enough
for
the
foundation
but shearing
strength is
150;170t/nri.
2.
Design
Therefore,
the
feature
of the design
of this dam
is its large fillet
(additional
cross section,
the
gradient
1 : 0.6) on the
side,of
upstream
to
secure
th€ safety against
sliding which
is very important
factor for
designing
cioncrete gravity
dam of
Inrs nersht.
3. Foundation
On the
foundation
of the dam and the
ridge of.th€
ght
abutment, consolidation
grouting
and
curtain
grouting
works
have been
carried
out.
Crcnsolidation
grouting
has been executed
before
mncrete
plac€ment
normally,
but at the
faults
of the right-abutment
grouting
works
have
been
done after concrete
placement.
Grout holes were drilled
in a zigzag
line with
a space of
5m in
the direction
of dam
axis and with
a space
of 6m in the
stream direction. The hole
depth is
tSm witU
a stage
grouting
and
the
hole diameter
is 46mm.
. . _The
main
curtain grouting
works
have
been carried out from the gallery.
The
hole depth
is
50
percent
of the dam
height
at
this
point
and
the minimm
depth is 15m.
The holes were bored
in a ziga.g
line with
a space
of 3m. The
sub
curtain grouting
have
been carried out
on the footing
of the upstream
side. The hole
depth
is 2b
percent
of the dam
height
at this point
and
the minimm depth
is 10m.
The holes were drilled with
a space
of 3m.
4,
Construction
.
.
Because
of
the large
base
thickness
(about
100m), for
the concrcte
placement,
block
construction
method
(3
block
divi-
sion)
under
El.
301m
and construction
method without
longitudinal
joint
above El.
301m were
adopted.
The deDth of
one
concrete
lift is
2m
wbich
is divided 4laye$
to be vibrated.
. _The
dam
condete
Placement
was
performed
by using a
one-tower-travelling
cable crane (the
fixed
tower on the
right-
bank,
the
travelling
tower
on the left-bank).
The
hoisting capacity is 20t
lyhich
is the targest
for
carrying
concretJ in
Japan.
It
took
about
four
yea6
to complete
the concrete worki.
For the
longitudinal
and
iansversal
joints,
joint
grout-
rng was
executed
after
lowering
the tempenture
of dam
body to the final
stable temfrerature
by an
artificial
concrete
cool-
ing
by embedded
pipe
coil.
.
To
divert
stream
flow
during construction
of the
dam, two-stage dive$ion
method
was
adopted
because
of the large
peak
discharge
of
flood,and
topographical
and
geological
features
of the dam
site.
5.
Intake
In
order
to divert
clean and sutface
warm
water,
selective intake was
adopted.
The
q/pe
is a
steel semicirqular
triple
leaf
roller gates.
It is
normally
operated automatically
in harmony
with reservoir
surface viried
to
take
suface water
but
oPerated
manually
in
case
of flood time.
The maximum
intake discharge
is 65mr/s
at the
depth
of
water
intake
is
4m.
At
present
this facility
is effectively
functioning for
the
purposes
above-mentioned.
90
UPSTREAM
VIEW
29,
SHIMAJIGAWA
DAM
Location
Nearest
City
.
River
Purpose
Catchment
area
Mean
annual
discharge
Years
of construction
.
Type
Foundation
Height
Crest
length
Volume
Spillway
Type
................,.
.....
Uncontrolled
Type
and
number
of
gate
......................
-
Maximum
dischalge
capacity
.................
750m%
Reservoir
Gross
capacity
..........
20.6x lffmj
Effective
capacity
...... 19.6X
1Om3
Area
..................
...,.
0.gkm.
Drawdown
range
.................................
49.6m
Owner
................
...........
Ministry
of Construction
Engineering
by
...............
Ditto
Construction
by
.....................
J.
v.
of Obayashi-Gumi,
Ltd.,
and
Omoro-Gumi
Co.. Ltd
1.
Profile
Shimajigawa
dam
is
a concrete
gravity
dam constructed by
Ministry
of Construction,
Near
the dam
slte the
dver bed
rs
nan_ow
where
the valley
is
so-called V-shaped gorge
of steep slopes
of about
40 degree
at both
abutments.
The founda-
tion
of
the
dam
mainly consists
of
sandy schist, green
schist and
black schist.
The
feature
of this
dam
is that it
is a natural
regulation
type
having
no
gates
but utilizing
an orifice
and crest for
flood
regulation
since
it has
only a
relatively
small
catchment
area.
Shinnanyo-shi,
Yamaguchi-ken
Shinnanyo-shi
Shimaji
Flood
control,
Maintenance
of normal
function
of the
river
water
and
Watersupply
32km2
1.4m3ls
1976-198r
Gravity
Sandy schist,
Green
schist
and
Black
schist
89m
240m
317,000m'
"r$$
s
GENERAL
PLAN
91
2. RCD
Method
The design
of
SNmajigawa
is comparatively simple
since it is a
gateless
orifice-equipped dam. In view of the topog-
raphical
and
geological
conditions of the damsite,
it was difficult to
install
a
mobile cable crane,
and because of the condi-
tion that this was
to be of medium size for a
gmvity
dam, the RCD
(Roller
Compacted Dam-concrete) Method was
adopted for
the first time for dam-body construction in Japan.
This RCD Method consists of altering the conventional
method of
consolidating concrete using intemal vibmto$ to use
general-purpose
construction equipment
for transporting
and
placing
concrete to spread it out in a layer over a
wide area. The method aims for rationalization of construction
through
compaction
of lean-mix, zero-slump conffete
with vibratory rollers.
3. C-onstruction
by RCD method
(1)
Concrete manufactured at
the
batching
plant
using a
forced-mixing type mixer was discharged
into bucket. This
RCD was
of exta-dry consistensy of z€ro slump and
lean mix design and maximum
size of the coarse aggregate is
80mm.
(2)
Concrete discharged into a bucket
(4.5m1)
was hauled underneath a stationary cable crane
(13.51)
installed near the
dam
axis by bunker line and was conveyed to the
dam body by the cableway.
iii.r
b
TYPICAL
92
CROSS
SECTION
(Overflow
Section)
ro
5m
Concretes
Grade
Max.
Sizs
Agg.
mm
w/c
(w/c+
F)
Fly
Ash
Ratio
(F/C+F)
o/o
Sand-
Agg.
Rutio
(sla)
Vo
Slump
cm
Air
Contenl
Vo
Water
(w)
kg/m3
Cement
(c)
kg/ml
Fly
Ash
(F)
kg/mr
Fine
Agg.
(s)
kg/mJ
Coarse
Aee.
(61
kg/ml
Admix.
kg/m3
A
80
0.591
30
34
4r
1.5
3.5+l
130
C-tF:220
610
r,377
0.55
154
66
B-l
80
0.808
30
34
1.5+1
105
C*F:130
749
1,476
0.325
91
39
B-2
80
0.87s
30
34
1.5+1
105
C*F:120
752
1,482
0.30
84
36
C
80
0.491
30
JI
4+1.5
3.5+1
740
C*F:285
593
1,347
0.713
199
86
D
80
0.761
30
34
4+ 1.5
3.5+1
r37
C*F:180
687
1,353
0.45
126
54
(3)
Concrete
conveyed
by
cable
crane
was
temporarily
received
at a
mobile
hopper (14.0m3)
set
on the
dam
body
from
where
it
was
hauled
by
dump
truck.
(4)
Surfaces
to
be
concreted
were
primed
by
uniformly
spreading
mortor
manually
to
a
thickness
of 1.5m
on
concrete
and
2m
on bedrock-
Bedding
motor
spread
on horizontal
construction
joints
before
placing
of concrete
is ex-
tremely
effective
in
preventing
rock
pockets
due
to
segregation
at
the
time
of
dumping
and
in
facilitating
band
at
the
joints.
(5)
Concrete
hauled
inside
the
dam
body
area
by dump
iruck (1lt)
was
dumped
on
the
horizontal
construction
joint
surface
and
spread
evenly
in
a thin
layer
by bulldozer.
An
extremely
wide-area
layer
system
was
adopted
for
concrete
placement
with
spreading
done
by bulldozer
(12t),
Transverse
joints
were
provided
lift
by lift
employing
a vibratory
press-in
type
joint-.itt"r.
The vibratory
joint-.
cutter
developed
at
Shimajigawa
Dam
used
a backhoe
as
the
basic
machine
ind
made
transverse
joints
by
forcing
in
a
galvanized
steel
plate
(thickness
0.27mm)
after spreading
by
bulldozer
(8)
compaction
was
done from
the
surface
using
a Bw-i00
vibr;to;y
roller
(70
with
two passes
without
vibration
and
nule passes
with vibration
made
in the
case
of a 50cm lift.
(9)
Slnce
there was
no
bleeding
as with
conventional
dam
conqete,
and practically
no
laitance,
green
cuung
was
per-
formed
after
elapse
of
a
given
length
of time
using
the brushes
or a
motorizel
t;;;;;-;;'.:;;;"
loose
rock
and
mortar,
upon which
washing was
done with
water.
(10)
For
curing,
besides
continuous-
cooling
after placement
by water
sprinklers
and
water
mats,
separate
misting
de-
vices
for water
jets
were
installed
on ihe
darn
body to
eject
water
into
the
air
so that
the work
site
would
con-
tinuously
be
enveloped
in a
misty
condition.
In
the winter
time,
the
surface
of
"on"t","
fru""J-was
cured
provid-
ing
heat
with
electric
heating
mats and
incandescent
lamp.
4.
Quality of
RCD
core
boring
was
preformed
from the
dam
body
and
as a whole
the
trends
described
below
were
recognrzed.
(1)
of 91.
specimens
at age
91 days.
only onqwas
less than
110kg/m,
troq[ej
'niii
,h.;;;;;ii;;,,';:,
for the
various
_^.
samples
being
150kg/m,
at
upper
layers
and
190kg/ml
at lower-layers.
(2)
There
was practically
no
difference
between
upp-er
and lower
layers,
and
it
was possible
to
place
conqete
which
was
comparatively
good
and
uniform.
(3)
The permeability
coefficient-was
about
1x 10-?--'qn/sec,
and
even.though
the
upper
section
appeared
relatively-
porous,
there
was
no fear
of
reakage,
and it looked
extremery
good
in
overall
visuJ
insoection.
(6)
(7)
;er-
ssbq--
I
=-
F\
L
-
EL 300
i
Crest
lengtfi
2499
t
t5
Olq
o
--
225
o
UPSTREAM
FACE
93
30.
SHIMOKUBO
DAM
Location
Nearest
City
.
River
Purpose
Catchment
area
Mean
annual
discharge
Years
of
construction
.
Type
Foundation
Height
Crest
length
Volume
Spillway
Type
Type
and
number
of
gate
Maximum
discharge
capacity
Reservoir
Gross
capacity
Effective
capacity
Area
Drawdown
range
Owner
Engineering
by
Construction
by
Kamiizmi-mura,
Kodama-gun,
Saitama-ken
(right
bank)
onishi-cho,
Tano-
gun,
Gunma-ken
(left
bank)
Fujioka-shi
Kanna
Flood
control,
Maintenance
of normal
function
of the
river water,
Water
supply and
Hydroelectric
323km'z
9.2m3ls
1959-1968
Gravity
Green
schist
I29m
598m
1,345,000m3
Controlled
Crest radial gatexz
and
Orifice
radial gateX2
1,600m3/s
130X
106m3
120X.
106m'
3.3km'?
73.7m
Water
Resources
Development
Public
Corporation
Ditto
Kumagai-Gumi
and
Hazama-Gumi,
Ltd.
1.
Geology
The
geology
of the dam
site is mainly
greenish
schist of tie
polaozoic
era.
2.
Design
The project
consists
of a
main and an auxiliary
dams, and takes the shape
of
"L"
in the plan.
Both dams
are condete
gravlty
structures.
The
contact of the main
and auxiliary dams is not
a key
joint
but
a conventional
joint.
Tranwerse
and tongitudina.l
joints
are
crmented by
joint
grouting
after artificial
cooling
by embedded
pipe
coils was
completed.
However,
the
ioint
at the contact
of main and auxiliary dams was
not
grouted.
From
topographic
configuration, the
auxiliary dam is constructed
on a ridge on
the
ght
bank
and the ridge itself
structurally
functions
as a
part
of the auxiliary
dam. The rock
surface of the ridge
in the reservoir
side is faced with
con-
crete
slab
and asphalt,
as
protection
against weathering
and seepage
of water. Between
the
bedrock and
facing,
porous
coqcrete
is
placed
to
drain water which appeared
into the drainage tu[nel
and then
released
to the downstream.
3.
Foundationtreatment
Foundation
treatment for both
the
main and
auxiliary dams is carried
out by consolidation
and curtain
groutings
to
make
the
formation
firm and watertisht.
4.
Construction
Blastfurnace
@ment
was used for the
concrete.Sand and coa$e
aggregates
(max
150mm)
were
manufactured ftom
quarry
run
rock.
Construction
facilities
for
the dam were designed
to suite the topography of-the
site and
shape of
the dam. Concrete
placing
facilities
adopted
are
jib
cranes mounted
on trestles constructed at
the different
elevations.
5.
Intake
_^I9.u!91V
warm
water
for idgation.
a selective
intake tower to dralv surface water
was
installed
in
3
years
from 1975
to 1978.
This
facility
is effectively
functioning
for the benefit of the inigation in
the downstream
Dlains.
94
PLAN
TYPICAL
CROSS
SECTION
95