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Tile or brick linings are similar in their advantages and disadvantages
to linings constructed of precast concrete slabs. Brick linings
can be used advantageously:
- If inexpensive manual labour is available.
- If materials for
tiles or bricks are available nearby.
- If materials and machinery
for other suitable types of linings are too costly.
The use of tiles and bricks for irrigation in the world have
been largely confined to the plains of India and Pakistan (Kraatz,
1977).
The most frequently used form of this type of lining is reinforced
double-tile lining, which has successfully reduced seepage
rates to 30-70L/m2/day. Interestingly, the bricks that are
used are
a very porous clay and therefore play very little part in the
seepage
control. The watertightness of the brick lining is solely due
to the plaster sandwich between the layers of bricks. The bricks
only
form a skeleton to hold the plaster or function as a protective
cover. Brick linings have also been constructed with an asphaltic
or synthetic membrane between or under the bricks. Bricks with
a glazed top surface have been used to reduce the reliance
on the plaster between bricks for effective seepage reduction
(Sally,
1965).
Recently the use of soil-cement tiles has been investigated,
with the laying of tiles prepared from local soil mixed with
the optimum
percentage of cement and water, in a laboratory channel. Overall
results showed that a lined channel with soil-cement tiles
has very low seepage rates and is resistant to erosion, and
can to
yield satisfactory results, especially where adequate coarse
aggregate for concrete lining is not available (Rahimi and
Abbasi, 1999).
Clay tiles are used successfully in India. The tiles are moulded
by hand and baked in a kiln the same way as earthen water pots
or roof tiles. The tiles are joined with cement mortar. To
prevent damage, humans and animals should not be permitted
to walk in
the channel. When protected from external damage, the clay
tile lining
lasts several years (USAID, 1970).
Linings of stone masonry have also been employed in areas where
suitable materials such as sandstone or basalt are available.
The construction of stone linings is relatively slow and labour
is
a major expense, as the stones are placed by hand. Seepage
losses can remain very high if the stones are not mortared
(Kraatz,
1977).
| Related
pages |
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Hard
surface lining techniques
Concrete
Shotcrete
Grouted fabric
mats
Soil-cement
lining
Flumes and
pipes
Asphalt |
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