units settled causing exposure of underlayer stone between Profiles 4 and 5
(Photos A45 and A46).
Overtopping
Observations during the experiments showed that overtopping was essentially
the same for Plans 1 through 1C and for Plans 2 through 2D, because only the
toe stability configuration differed between plans. All Plan 1 series experiments
were conducted with 8- and 11-tonne Core-Locs, and the head portion of the
breakwater was +5 m CD. The Plan 2 series of experiments consisted of all
11-tonne Core-Locs and the head portion of the breakwater was +8 m CD.
Overtopping was classified as minor, moderate, or major. Minor overtopping
was defined for the present study as occasional or no overtopping. Moderate
overtopping was defined as regular overtopping with occasional green water.
Conditions that produced frequent overtopping and green water were classified
as major.
The classification of overtopping (minor, moderate, or major) is plotted
versus wave condition in Figures 17 through 19. The wave conditions in the
figures are labeled from left to right by the sequence in which they were gener-
ated during the experiment, i.e., 13-sec, 3.0-m waves were generated first and
19-sec, 6.7-m waves were generated last. Figure 17 shows the amount of over-
topping that occurred at the trunk for all plans. Major overtopping occurred at
the trunk for 16-sec, 6.7-m waves, but was minor or moderate for all other
conditions. Figures 18 and 19 show overtopping classifications for Plan 1 and
Plan 2 series experiments at the head, respectively. The figures illustrate the
reduction of overtopping by raising the crest elevation to +8 m CD (Plan 2
series) from +5 m CD (Plan 1 series).
Summary
Stability plans tested are summarized in Table 4. Based on experiments con-
ducted on the three-dimensional model of Vale de Cavaleiros breakwater,
11-tonne Core-Locs are stable on the structure if the toe is stable. It was
necessary in the model to simulate a trench having a near vertical face and a
depth of 1.5 m. No reduction in stability was observed by raising the +5-m CD
portion of the breakwater to +8 m CD.
25
Chapter 3 Results
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