SMALL DAMS PETITS BARRAGES

sloping core guarantees water impoundment of the dam, the rockfill improves the stability of
the masonry, and the filter layers ensure effective and long term functioning of the clay core.
The Zhaogushe dam has a cross section composed of five parts as shown in Fig. 2.8.
Fig. 2.8 – Cross section of Zhaogushe type overflow dam, China [1].
2.4 STONE MASONRY DAMS
Large pieces of stones have been used in the construction of dams since the
construction of Sadd El Khafara dam, in Egypt, about 20km south-east Cairo, 4.600 years ago,
one of the oldest dams ever registered. In this dam it is estimated that about 17 000 revetment
blocks on both outer faces, each weighing 300 kg, had been carefully placed and part of them
still exist until our days.
Ancient large stone masonry dams, however, are scarce, and most of the large stone
masonry dams in China were built more recently. All together, 1,000 stone masonry dams of
various types were completed from 1949 to 1977.
The reasons for the rapid development of stone masonry dams in China are many. In the
first place, they favor the use of local materials in mountainous regions where rock materials
are available in greater quantity than soils. The volume of a masonry dam is smaller than that
of an earth dam. Masonry dams can save on timber, steel and cement. Moreover, the crest of
a stone masonry dam permits overflowing, thereby solution is rendered easier for river flow
diversion and passage of floods during construction.
Fig. 2.9 – Straw-raincoat dam, China [1].
1 – Dry-laid masonry
2 – Sloping clay core
3 – Rockfill
4 – Filters
5 – Rough interface
6 – Cutoff
7 – Rock foundation
1 – Dumped rockfill
2 – Earthfill clay
3 – Foundation of
sand and gravel
21