Page 160 - Water Standards
P. 160

shall be paved uniformly, poured and tamped, and patted
                                to compaction. After being preliminarily flatted, a layer of
                                1- 2mm thick cement should be spread on the surface,
                                and kneaded, pressed and trowelled immediately. Paving
                                shall be carried out continuously. The mixed material
                                should be paved within 1   5 hours starting from wet⁃mixing.
                             4) For paving dry cement soil, the form shall be set up first,
                                and then material shall be paved and tamped layer by
                                layer. The paving thickness of each layer should be 10 -
                                15cm, and layer joints shall be scarified and watered.
                             5) Plastic cement soil is usually as a protective layer, the
                                protective layer shall be paved before the initial setting of
                                the plastic cement.
                       3   4   6  Stone masonry anti⁃seepage shall meet the following require⁃
                       ments:
                           1    Masonry sequence. For trapezoidal open channels, the
                       channel bottom should be laid before that at channel slopes. For a
                       channel slope, stones shall be lined starting from the slope toe to up⁃
                       ward layer by layer. For U⁃shaped and radial open channels, stones
                       shall be lined starting from the center line of the bottom to both sides
                       symmetrically. For rectangular open channels, the flank walls may
                       lined first, then the bottom. For arched and box⁃type closed conduits,
                       the flank wall and channel bottom may be started first, and then the
                       top arch or capping plate may be laid. As the bottoms and slopes of
                       various open channels are lined, the sealing capstones shall be laid in
                       time.
                           2  Stone layout provisions. Large and regular stones shall be laid
                       at the channel bottom and slope toe. The long sides of the stone work
                       and slabstone shall be laid along the flow direction at the slope, and
                       perpendicular to the water direction at the channel bottom. Masonry
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