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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