Page 159 - Water Standards
P. 159

Table 3   4   4-2  (Continue)

                                     Item                Allowable deviation value (mm)
                       Longitudinal blocking length of slope and bottom
                                                          ± (5-10)     ± (5-10)
                          at in⁃situ poured anti⁃seepage structures
                       Transversal blocking length of slope and bottom
                                                          + (30-50)   + (10-60)
                          at in⁃situ poured anti⁃seepage structures
                          Length difference between two diagonal
                                                            ±7           —
                                lines of precast slabs
                                          In⁃situ placement  ±5%      -5%--15%
                         Thickness of anti⁃
                                         Stone masonry and
                         seepage structure               ± (5%-10%)      —
                                           precast blocks
                       Note: The larger values are applicable for large and medium⁃sized channels, and the
                           smaller values for small ones.
                      3   4   5  Cement soil anti⁃seepage shall meet the following require⁃
                      ments:
                          1  Soil shall be air dried and pulverized, and passed through a
                      5mm aperture sieve. Measures against rain and humidity shall be taken
                      to protect the cement.
                          2  In⁃situ paving of cement soil anti⁃seepage structures shall be
                      carried out according to the following steps:
                            1) Batching shall be carried out according to the design mix
                               proportion, and the allowable deviation in weight shall
                               meet relevant requirements. The time for mixing and pav⁃
                               ing, or mold packing and forming of the cement soil shall
                               not be larger than 60min.
                            2) Cement soil should be dry⁃mixed first, and then wet⁃
                               mixed to uniformity.
                             3 ) Before plastic cement soil is paved, the channel
                               foundation shall be wetted by purling water, and an ex⁃
                               pansion joint form shall be set up. Channel slopes shall be
                               paved before the channel bottom. Cement soil material
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