Page 179 - Water Standards
P. 179

cording to the shaft diameter and section shape, and be looped to⁃
                       gether. Form height shall be determined on the concrete setting time
                       and form climbing rate, and the climbing rate generally should be 1   0
                       -1   4m/ d. The form shall be coned shape with the bottom slightly
                       smaller than the top, the taper is usually 1%, and the strength of the
                       stripping concrete should be 0   1-0   3MPa.
                           4  The circumferential and longitudinal construction joints of
                       concrete shall not only be chiseled as usually, but key ways shall also
                       be made. If there are waterproofing requirements, water⁃stops shall be
                       installed.
                       3   7   9  Construction safety operation shall meet the following require⁃
                       ments:
                           1  When the pilot shaft and shaft body or shaft entrance are con⁃
                       structed at the same time, reliable sealing measures shall be used to
                       prevent anything from dropping into the pilot shaft, thereby
                       influencing operational safety.
                           2  A shaft depth indicator shall be set up when a lifting facility
                       is adopted in a shaft to prevent overwinding and overspeed, and there
                       shall be protection devices for overcurrent and voltage loss, as well as
                       a braking system. There shall be reliable communication and signal
                       connections, and the signals shall include sound and light.
                           3  A foot ladder with guardrail shall be installed in the shafts,
                       and a resting platform shall be made every 8m.
                                            3   8  Penstocks


                       3   8   1  Underground buried pipe excavation shall meet the require⁃
                       ments in Section 2   4 of this specification.
                       3   8   2    The concrete construction of underground buried pipes
                       without steel board lining shall meet the following requirements:
                           1  Inclined shaft concrete lining should be poured with sliding
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