Page 129 - Water Standards
P. 129
dry naturally. Binders can be warmed to meet the require⁃
ments of construction progress in the winter with a maxi⁃
mum temperature up to 60℃.
5) When geomembranes of the core wall are laid vertically,
they shall be laid in a zigzag pattern. If longitudinal ex⁃
pansion joints are made in the direction of the dam axis
as required by the design, it is recommended to use
composite geomembranes to reduce the friction of layers
when the joints have been expanded. If a simplex
geomembrane is used, protective measures shall be a⁃
dopted on both sides of the geomembrane, such as
adding a transition layer of fine particles or geotextiles.
Vibrating rollers cannot be used in the backfilling area
which is in the range of 50-100cm from both sides of the
core wall, whereas frog rammers can be used in this
area. If there is clay on one side of the geomembrane,
the method of retaining⁃plank can be adopted in the con⁃
struction. The offset between the actual axis and the
design axis of the geomembrane shall not be larger
than 10cm.
6) The hot melt adhesion process shall meet the relevant re⁃
quirements in SL/ T 231
3 The laying of composite geotechnical materials on the dam
slope and sloping core shall meet the following requirements:
1) When coiled materials are laid on the dam slope, they
should be rolled out and laid from top to bottom. Treatment
of joints shall be done well.
2) Workers shall wear soft shoes when laying geomembranes.
The materials shall be well covered to avoid damage by
sunshine and wind. Geomembranes on dam slopes can be
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