5
Summary
A three-dimensional physical model study was conducted to test stability of
the proposed breakwater rehabilitation at Vale de Cavaleiros. The direction of
storm waves was 300 deg from the north. The series of waves generated on the
model was equivalent to a 17-hr storm prototype. The storms initiated with
moderate waves of 3 m and were incrementally increased in height up to a depth-
limited height of 6.7 m.
Results
Results of the model study indicated:
a.
The armor units selected for the original design were stable if the toe
was stable. Plan 1C, which included 8- and 11-tonne Core-Locs, and
bundled steel chain to anchor the breakwater toe, was stable during
original and repeat tests. However, it was noted that the 8-tonne units
rocked in place during tests and were considered moderately stable.
Subsequent tests included 11-tonne Core-Locs on the entire structure,
but a constructable prototype toe anchor was still required.
b.
Plans 2A and 2B included a board anchored to the model floor at the
base of the breakwater to stabilize the toe. Analogous results would be
expected if a toe trench was used to fix the toe. The board used in Plan
2A was 1 m deep and included a 45-deg angle adjacent to the toe units.
The sloped trench was stable for waves up to 16 sec, 5.2 m but signifi-
cant damage occurred between Profiles 8 and 9 for 16-sec, 6.7-m waves.
The trench simulated in Plan 2B was 1.5 m high and had a vertical face.
Plan 2B was stable for original and repeat tests; one unit was displaced
during the repeat tests, but the structure remained stable.
c.
Different toe reinforcement schemes such as a stone buttress of 0.75- to
1.8-tonne stone (Plan 1A), 11-tonne Core-Locs (Plan 2) placed at the toe,
and concrete-filled cargo containers (Plans 2C and 2D) placed at the toe
were tested, but were unsuccessful in stabilizing the toe.
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Chapter 5 Summary
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