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Unformatted text preview: 3, and raised concerns
regarding the ability to produce large armour stone. As a result, initial design
development for the breakwater assumed concrete armour units (see below).
More detailed quarry investigations were undertaken in 2004, including
surface outcrop and scan-line mapping, coring, sampling and testing programs,
and fragmentation and yield analyses. These investigations identified a wide
range in stone materials in the N-S-W hill complex, with quality ranging from
marginal to excellent. In addition, the fragmentation and yield analyses
indicated that there was a sufficient quantity of stone available to meet the needs
of this project (in fact there was excess capacity). In addition, it was concluded
that the upper limit on armour stone size would be limited by production
methods and equipment rather than by inherent limitations in the in situ rock.
Based on this information, detailed design development for the breakwater
focused on a berm design, assuming a maximum stone size of 20 tonnes (see
EVALUATION OF ALTERNATIVE BREAKWATER DESIGN CONCEPTS As noted above, initial design development for the breakwater assumed the
use of concrete armour units due to uncertainty related to the availability of
large armour stone. Single layer units, such as the AccropodeTM and CoreLocTM, were identified as the most “efficient” approach to resist the design wave
conditions. However, the requirement to place the units in persistent swells, as
well as the large size of the units, raised two significant concerns: 7 1.
2. Ability to achieve required placement in swells (filter and armour);
Risk of breakage during placement (and in service). The first issue was addressed in a set of two-dimensional model tests
designed specifically to assess the impact of placement in waves on the stability
of the armour layer. These tests, undertaken by HR Wallingford, included tests
with both AccropodesTM and Core-LocsTM (12 and 16 m3 units), as well as tests
with various placement scenarios, including:
• Individual placement “in the dry” (typical in models, but not realistic);
• Simulated crane placement (refer to Figure 6), including:
o Varying wave...
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This note was uploaded on 02/04/2014 for the course HE 8450 taught by Professor Verhagen during the Spring '14 term at Technische Universiteit Delft.
- Spring '14