Page 158 - Water Standards
P. 158
ment soil, stone masonry, concrete, geomembrane, asphaltic con⁃
crete, etc. The technical requirements of materials are listed in rele⁃
vant regulations.
2 The deviation in elevation, size and smoothness of unlined
cross sections shall meet the requirements of Table 3 4 4-1
Table 3 4 4-1 Allowable deviation for the channel section
Allowable deviation (mm)
Item
Soil channel Stone channel
Bottom elevation ± (20-30) ± (30-50)
Centerline 20-30 30-50
Bottom width + (30-50) + (50-100)
Top opening width + (40-80) + (50-100)
Top elevation of the dike + (20-30) + (50-100)
Smoothness of bottom and inside slopes <30 for convex
± (20-30)
( checked by 2m length ruler) <100 for concave
Note: The larger values are applicable for large and medium⁃sized channels, and the
smaller values for small ones.
3 Allowable deviations in smoothness and size of the lined
channels are listed in Table 3 4 4-2.
Table 3 4 4-2 Allowable deviations of lined channel
Item Allowable deviation value (mm)
Channel bottom elevation ± (10-30) ± (10-20)
Channel centerline ± (10-30) ± (10-20)
Channel bottom width + (20-40) + (30-50)
Upper opening width of section + (30-50) + (40-60)
Smoothness ± (10-20) ± (10-20)
In⁃situ placement ±20 ±20
Expansion joint interval
Precast concrete ±50 —
Oblique length of slope of anti⁃seepage structure + (10-20) + (10-20)
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