Environmental Engineering Reference
In-Depth Information
0.00%
Foz Do Areia (ff
0.5 to 0.9)
Reece (ff1.3 to 1.46)
Shiroro (ff
0.05%
1.8)
Kotmale (ff
0.54 to 1.04)
Aguamilpa (ff
0.48 to 1.83)
End of first filling
0.10%
0.15%
0.20%
0.25%
0.30%
0.1
1.0
10.0
100.0
Time (years since end of main rockfill construction)
Figure 15.38.
(Continued).
Table 15.9.
Post construction total crest settlement and long-term creep rate for CFRDs (Hunter, 2003;
Hunter and Fell, 2002).
Total post construction
settlement (% of dam height)
Long-term creep
Rockfill classification
10 years
30 years
rate (%/log cycle)
Dumped Rockfill
0.6 to 1.0%
1.0 to 1.5%
0.3 to 1.5
Well compacted rockfills
- Medium to high strength
0.15 to 0.4
-
0.05 to 0.25
-Very high strength, quarried
0.06 to 0.2
-
0.02 to 0.10
- Gravel Rockfills
0.2 to
0.05
-
0.10
Notes: (1) Rock substance unconfined compressive strength medium 6-20 MPa, high 20-70 MPa, very
high 70-240 MPa.
gravel will be significantly greater than that of angular quarried rockfill. Hence, the
contact stresses will be significantly less, resulting in less particle breakage.
Table 15.9 summarises the range of total post construction settlement at 10 and 30
years, and the long-term creep rate determined from the data set of CFRDs.
15.6.3
Face slab displacements and cracking
Table 15.10
summarizes maximum observed face slab displacements.
The maximum displacements usually occur at about mid height of the dam, but this
may vary depending on the zoning of the rockfill, and whether the face slab was con-
structed in one stage after all the rockfill was placed, or in several stages. Displacements
at the crest are usually less than the maximum but the ratio varies, particularly if the reser-
voir impoundment begins before the dam was completed (as in Tianshengqiaol dam, Wu
et al., 2000).
Table 15.11
summarizes perimetric joint details and maximum observed displacements.
It is apparent from the data presented in Table 15.11 that the maximum opening, set-
tlement and shear measured on perimetric joints of CFRD is typically less than 20 mm.
