5. Rubble Mound Structures
181
involves the test criteria by changing the slope for both head and trunk
section of breakwater armoured with KOLOS. The KD value was evaluated using the well-known Hudson’s formula both for the trunk and head
sections.
The hydraulic stability of breakwater armour units is determined by
wave height, unit size, spécifie density (of armour unit and sea water) and
by the shape of the unit. The Stability Co-efficient (Kp) can be derived
using the Hudson’s formula given in Eq. (5.1). The Hudson’s formula can
be written in terms of stability number (ATS) as:
H
Ns = ~KD~ =
cota)1/3
(5.2)
A - relative density = [(pc/Pw) — 1] and Dn = nominal diameter of armour
unit (V1/3).
Prior to obtaining the value of Kd for KOLOS, the damage level was
fixed in line with the proposed guidelines on the classification of damage levels suggested by d’Angremond and van Roode [2004]. For an armour slope of
1 in 1.5, no repair is needed for an initial damage (no repair of armour)
of up to 0.5% for DOLOS, irrespective of the weight of the individual unit
of the armour layer and as KOLOS is an improved version of DOLOS,
the same damage level has been incorporated in this stability study. The
initial part of the study focuses on the establishment of the Hudson’s stability coefficient of KOLOS, where the test sections had been subjected to
the maximum wave height it can withstand without being damaged extensively. The maximum wave heights under the respective wave periods are
illustrated in Table 5.3.
The Hudson’s stability number has been established for KOLOS in order
to hâve comparisons with other armour units and as from the table above,
KOLOS can hâve a Kd value of up to 32, which is quite high, with a maximum damage percentage of 0.5%. Using such a high value for the design
can be justified because random placement and double-layer configuration
adds to the stability of the armour and even at a damage percentage of
0.5%, further infliction of damage cease to exist. The design Kd values
of KOLOS for different armour slopes and for spécifie damage conditions
are summarized in Table 5.4. It has to be noted down that these values
corresponds to non-breaking wave conditions. The details of the hydrodynamic characteristics of KOLOS are discussed by Chandramohan et al.
[2012],
181
involves the test criteria by changing the slope for both head and trunk
section of breakwater armoured with KOLOS. The KD value was evaluated using the well-known Hudson’s formula both for the trunk and head
sections.
The hydraulic stability of breakwater armour units is determined by
wave height, unit size, spécifie density (of armour unit and sea water) and
by the shape of the unit. The Stability Co-efficient (Kp) can be derived
using the Hudson’s formula given in Eq. (5.1). The Hudson’s formula can
be written in terms of stability number (ATS) as:
H
Ns = ~KD~ =
cota)1/3
(5.2)
A - relative density = [(pc/Pw) — 1] and Dn = nominal diameter of armour
unit (V1/3).
Prior to obtaining the value of Kd for KOLOS, the damage level was
fixed in line with the proposed guidelines on the classification of damage levels suggested by d’Angremond and van Roode [2004]. For an armour slope of
1 in 1.5, no repair is needed for an initial damage (no repair of armour)
of up to 0.5% for DOLOS, irrespective of the weight of the individual unit
of the armour layer and as KOLOS is an improved version of DOLOS,
the same damage level has been incorporated in this stability study. The
initial part of the study focuses on the establishment of the Hudson’s stability coefficient of KOLOS, where the test sections had been subjected to
the maximum wave height it can withstand without being damaged extensively. The maximum wave heights under the respective wave periods are
illustrated in Table 5.3.
The Hudson’s stability number has been established for KOLOS in order
to hâve comparisons with other armour units and as from the table above,
KOLOS can hâve a Kd value of up to 32, which is quite high, with a maximum damage percentage of 0.5%. Using such a high value for the design
can be justified because random placement and double-layer configuration
adds to the stability of the armour and even at a damage percentage of
0.5%, further infliction of damage cease to exist. The design Kd values
of KOLOS for different armour slopes and for spécifie damage conditions
are summarized in Table 5.4. It has to be noted down that these values
corresponds to non-breaking wave conditions. The details of the hydrodynamic characteristics of KOLOS are discussed by Chandramohan et al.
[2012],