Home
Download PDF
Order CD-ROM
Order in Print
Home
>
Coastal and Hydraulics Laboratory Fact Sheets
>
> Table 17. PHI VERSUS MILLIMETER PARTICLE SIZES
BEACH FILLS - sect54eng0116
Figure 84. Fill factors for Beach Fills ( After Hobson 1977 ) - sect54eng0118
sect54eng
Page Navigation
107
108
109
110
111
112
113
114
115
116
117
An
excess
of fill
will
have
to be placed
initially
because
the
finer
material
will
be
lost
from
the
beach
as
the
waves
sort
the
deposit.
The
amount
of
overfill
needed
to account
for
these
initial
losses
depends
on
the
textural
characteristics of
the
fill and
the
in-place
material.
These
are
compared by
using
measures
of
the
mean
grain
size
and
sorting
of
the
sand
samples
as
given
by
Hobson
(1977).
Sorting
is
an
indication
of
the
range of
particle
sizes
that
are
present.
A
well
sorted
sample
contains
particles
that
are'
approximately
the
same
size.
A
poorly
sorted
sample
contains a
gradation
of
particle
sizes.
Mean
grain
sizes
and
sorting
are
expressed
in
phi
units.
These
are
defined
as,
φ = -
log
2
d
(mm)
(18)
where,
d
(mm)
=
the
particle
diameter
in
millimeters.
Note,
log
2
d
(mm)
=
log
10
d
(mm)
/
log
10
(2).
Therefore
φ =
-3.32
log
10
d
(mm)
(19)
Table
17
compares
the
millimeter
and
phi
size
scales.
Table
17
PHI
VERSUS
MILLIMETER
PARTICLE
SIZES
φ
D
(mm)
256
-8
64
-6
8
-3
4
-2
2
-1
1
0
0.5
1
0.25
2
0.125
3
0.0625
4
An
estimate
of
the
mean
particle
size
is
M = (φ
84
+ φ
16
)/2
(20)
Where φ
84
and φ
16
are
points
on
the
gradation
curve
than
represent
the
percentage
of
the
sample
that
is
coarser
than
the
particular
phi
size.
Phi
sorting
can
be estimated by
115
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business