Plan 2B
Plan 2B was identical to plan 2A except the toe reinforcement was con-
structed using a board anchored to the floor to represent a toe trench 1.5 m high
with vertical sides (Figure 15). The breakwater armor was rebuilt and the
packing density for the 11-tonne Core-Locs was 0.63. To expedite the study, all
3.7-m waves and the 13-sec, 5.2-m condition were omitted for this test series.
From previous experiments with plans which included a restrained toe, the
omitted wave conditions caused no or only minor damage to the breakwater. No
units were displaced during this series (Photos A34 through A36). Plan 2B was
rebuilt with the same packing density and the experiment was repeated. One
Core-Loc was displaced off the head midway through 19-sec, 6.7-m waves, but
the structure remained stable throughout the rest of the wave condition.
Plan 2C
The breakwater was rebuilt entirely of 11-tonne Core-Locs ( =0.63), but the
board used to simulate a toe trench was removed between Profile 4 to a location
70 m from the elbow (Figure 16, Photos A37 through A39). Model concrete
blocks were placed in this area to simulate 6.1-m-long, 2.5-m-wide, 1.2-m-high
cargo containers filled with concrete. The containers had an approximate
prototype weight of 42.4 tonnes using a concrete specific gravity of 2.3 in the
prototype. The containers were placed 1 m apart along the toe and 11-tonne
Core-Locs were placed against the containers.
The structure was subjected to all waves listed in Table 3. The containers
began to displace during 13-sec, 3.0-m waves and movement of containers
increased as wave height increased. However, the containers provided some
sheltering and prevented unraveling of the Core-Loc toe up to 3.7-m waves for
all three periods. Waves higher than 3.7 m for all periods displaced the con-
tainers out of the section and moved them southward along the toe and around
the elbow to the head (Photos A40 through A42). After the containers were dis-
placed from the original section, toe units in the area were displaced and upslope
units slipped, causing significant exposure of the underlayer stone between
Profiles 4 and 5 (Photo A40).
Plan 2D
Plan 2D was identical to Plan 2C except the cargo containers were placed end
to end along the Core-Loc toe (Figure 16, Photos A43 and A44). The armor
layer was rebuilt with a packing density of 0.62. Results were similar to experi-
ments with Plan 2C; the containers began to displace during 13-sec, 3.0-m waves
and movement continued with higher waves. Eventually, all containers were
displaced from their original position and moved southward along the break-
water. Without toe protection, Core-Loc toe units were displaced and upslope
22
Chapter 3 Results
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