Environmental Engineering Reference
In-Depth Information
Table 6.6.
Equations of best fit for core settlement (as a percentage of embankment height) versus
embankment height during construction (Hunter, 2003; Hunter and Fell, 2003d).
Equation for core settlement*
1
Core material/
No.
Std. err. of
R
2
*
2
settlement*
3
(%)
shape type
cases
(as a percentage of embankment height)
0.179 H
0.60
Clay cores - all sizes
42
0.77
0.41
Sandy and gravelly cores:
Medium to thick,
Plastic
0.079 H
0.76
25
0.81
0.39
0.063 H
0.72
Thin
5
0.70
0.47
0.187 H
0.46
Non-plastic
7
0.71
0.24
Notes: *
1
Settlement as a percentage of the embankment height, embankment height
H
in metres.
*
2
R
2
regression coefficient.
*
3
Std. err.
standard error of the settlement (percent of embankment height).
0%
1%
2%
3%
4%
5%
6%
7%
8%
0
250
500
750
1000
1250
1500
1750
2000
Estimated effective vertical stress (kPa)
Windemere - ES1
Medicine Creek - IVM A
Upper Yarra - ES2
Burrendong - Zone 1A
San Luis - IVM D
Chaffey - IVM A
Navajo - IVM A
Eppalock - IVM 1
Burrendong - Zone 1C
San Luis - IVM B
Glenbawn Saddle - IVM A
Steinaker - IVM A
Sasumua
Horsetooth - IVM A
Deer Creek
Upper Yarra - ES1
Glenbawn - IVM A
Horsetooth - IVM B
Figure 6.40.
Vertical strain versus effective vertical stress in the core at end of construction for dry
placed dominantly sandy and gravelly earthfills (Hunter, 2003; Hunter and Fell, 2003d).
Hunter (2003) and Hunter and Fell (2003d) conclude:
For the crest region, the data has been sorted based on core width, core material type and
placement moisture content, and indicates that:
-
The post construction crest settlements are generally much smaller than the core settle-
ment during construction;
-
Nearly all dams experience less than 1% crest settlement post construction for periods
up to 20 to 25 years and longer after construction;
-
Most experience less than 0.5% in the first 3 years and less than 0.75% after 20 to 25
years;
-
Smaller magnitude settlements are observed for dry placed clayey sands to clayey grav-
els and dry to wet placed silty sands to silty gravels;
