Environmental Engineering Reference
In-Depth Information
Table 12.4.
Damage classification system for embankment dams under earthquake loading (Pells and
Fell, 2002, 2003).
Damage class
Maximum longitudinal
Maximum relative
crack width
(1)
mm
crest settlement
(2)
(%)
Number
Description
0
No or slight
10 mm
0.03
1
Minor
10-30
0.03-0.2
2
Moderate
30-80
0.2-0.5
3
Major
80-150
0.5-1.5
4
Severe
150-500
1.5-5
5
Collapse
500
5
(1 )
Maximum crack width is taken as the maximum width, in millimetres, of any longitudinal cracking that
occurs.
(2 )
Maximum relative crest settlement is expressed as a percentage of the maximum dam height (from
general foundation to dam crest).
Zone 3/4 and 4/5 Boundary Not Defined
2,70
2/3,0
8
1,0 (Philippines)
1,0 (Philippines)
3,-
0,0
1,0
1,70
1,0 (Philippines)
1,0
1,-
2,-
3/2,10
1,70
3
1/0,0
1/0,70
1,0
2/3,-
1/0,0
7
1/0,14
2
2,29
1/0,-
1
3,- (piping)
1,0
1/0,0
6
0,0
2/3,-
0
0,70
0,0
Data Set 1
Data Set 2
Data Set 4
Data Set 6
Data Set 8
Data Set 9
Contours of
Damage
0,-
5
LEGEND
1/2, 14, L
0,70
0,0
Liquefaction
14 meters of alluvium
Class 1/2 Damage
4
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
(A)
Figure 12.34.
Earthfill Dams - contours of damage class versus earthquake magnitude and peak ground
acceleration. (A) Earthquake magnitude. (B) Foundation peak ground acceleration (as a
fraction of acceleration due to gravity). Contours drawn without consideration for cases
that had liquefaction (Pells and Fell, 2003).
- There are a number of mechanisms that can lead to formation of either of these types
of cracks. Many of these mechanisms are common to both seismic loading and normal
operating loading. There are seen to be more mechanisms that may lead to the forma-
tion of longitudinal cracks that transverse cracks, largely because lateral displacement
is more readily achieved in the upstream-downstream directions.
- For visible longitudinal cracks to occur the dam needs to experience a Magnitude 6.5
or greater earthquake, and a peak ground acceleration greater than about 0.15 g for
earthfill dams and 0.3 g for earth and rockfill dams. Alternatively it needs an earth-
quake of Magnitude 7.0 or greater, and a PGA of 0.05 g for earthfill and say 0.15 g for
earth and rockfill dams. For hydraulic fill dams, visible cracking may occur for
Magnitude 6 earthquakes, and 0.05 PGA.
