tlement at the base under a fill height of 183 ft. is 0.01 ft. No. 2 was placed on weathered rock, and settlement at the base under a fill height of 117 ft. had reached 0.21 ft. in November 1964.
Aluminium casings were installed in the embankment for measuring lateral movements with a slope in- dicator. Unfortunately, this instru- ment went out of service soon after coming into use. However, a settle- ment torpedo similar in principle to the U.S.B.R. torpedo enabled the internal vertical movements of each section of the casing to be measured.
оп
Surface settlement points and de- flection points were constructed each of the downstream berms as well as on the dam crest.
No ap- preciable surface settlement or deflec- tion has yet been recorded.
Summary
Approximately 1.6 million cu. yd. of materials were required to con- struct the Lower Shing Mun Main Dam which is a composite rock-and earth-fill embankment. Cost of this embankment is HK$15 million.
The earthfill used was completely decomposed granite which was ob tained from the hills nearby. Because of its abundance in Hong Kong, its high shear strength when properly compacted, and its good workability,
CIVIL ENGINEERING & PUBLIC WORKS
decomposed granite has been proved to be eminently suitable for earth dam construction.
were
The consulting engineers Binnie & Partners, London, and Scott & Wilson, Kirkpatrick & Part- ners, Hong Kong. The main contrac- tor was Nishimatsu Construction
Company Ltd.. Japan, and
the
transport sub-contractor was Oriental Development Co., Ltd., Hong Kong.
References
1.
2.
3.
RUXTON, B. P. & BERRY, D. (1957). Weathering of Granite and Associated Erosional Fea- tures in Hong Kong. (Geological Society of America, Bulletin Volume 68, pp. 1263-1292). LAMB, D.W. (1962). Decompos- ed Granite as Fill Material, with Particular Reference to Earth Dam Construction. (Sym- posium of Hong Kong Soils, Hong Kong Joint Group of The Institutions of Civil, Mechanical and Electrical Engineers, 1962). Bishop, A. W. Kennard, M. F., & PENMAN, A. D. M. Pore Pres- sure Observations at Selset Dam, (Proceedings of the Conference on Pore Pressure and Suction in Soils, London, 1960).
5.
BISHOP, A. W. (1957). Some Factors Controlling the Pore Pressures set up during the Con- struction of Earth Dams. (Pro- ceedings of the 4th Internation- al Conference on Soil Mechanics and Foundation Engineering, London 1957).
APPENDIX
Contractor's Plant for Embankment Construction
No.
Plant
3
D8 Bulldozer,
Caterpillar
2
B8U Bulldozer,
Caterpillar
2
D7 Bulldozer,
Caterpillar
6
Use
977 Traxcavator,
Caterpillar,
21⁄2 cu. yd.
955 Traxcavator,
Caterpillar
134 cu. yd.
Main dam, quarries borrow areas and access roads.
Main dam and quarries
PRESSURES
( X 1,000 LB PER SQ.FT.)
24
23
2차
31
20
19
17
16
15
14
נן
12
11
10
9
A
2
Motor Grader, Caterpillar
Main dam & access roads
4.
"Earth Manual" U.S. Depart- ment of the Interior Bureau of Reclamation.
2
38B Face Shovel,
Ruston Bucyrus, 11⁄2 cu. yd.
1
Face Shovel, Smith,
34 cu. yd.
Filter plant
and quarries
END OF CONSTRUCTIO
1
Truck Crane, Smith,
Main dam
25 tons
and others
1
Self-propelled
pneumatic-tyred
roller, Sakai, 22
tons
PIEZONETER
1
Vibrating steel roller,
Vibra-Verken,
4 tons
ABOVE PIEZOMETER
1
Vibrating pneumatic-
1
tyred roller, Japan į Machinery, 10 tons
Pneumatic-tyred
roller, Southwest,
40 tons (On hire
Main dam
compaction
OVERBURDEN PRES
OVERBURDEN PRESSURE
ABOVE
from P.W.D.)
PORE PRESSURE
1
Vibrating Wacker-
Plate
'
2
2
Vibrating Soil Com.
PORE PRESSURE CS
pactor, Shinwa
Kikai Kogy
с
4
Johnson Rammer
- 1
- 2
1964
'OCT1NOV'DEC! JAN'FEB MAR APR MAY JUN JUL AUG' SEP 'OCT NOV DEC | JAN |
1963
1964
5
Dump Truck, Foden,
1965
11 cu. yd.
110
901
9 8 2 8 2
Quarries and
19
Dump Truck, Isuzu,
main dam
6 cu. yd.
55
CI
50
40
3
C5
30
20
19
'OCT ' NOV' DEC❘ JAN' FEB 'MAR' APR MAY JUN 'JUL' AUG' SEP 'OCT NOV DEC | JAN
1963 1964
1964 1965
1
and access
roads
Filter Plant, 75
ton/hr.
End Tipping Lorries, Borrow areas
(hired locally)
Water Tanker, Isuzu, Main dam
1300 gal.
and Main
dam
Main dam
Crushing Plant, 50
ton/hr.
PORE PRESSURE
OVERBURDEN PRESSURE (%)
Fig. 7. Pore pressure recorded by piezometers C1 and C5 with relation to construction
Far East Architect & Builder December, 1965
77
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