ENGINEERING
A
INFORMATION
SYSTEM
FIELD
NOTESTECHNICAL
REPORTS
DATA RETRIEVALMANAGEMENT
PROFESSIONAL DEVELOPMENT
VOLUME
eld
1
NUMBER
11
Notes
Distribution Inquiry
Unified
Rock
Washington Office News
FOREST SERVICE
NOVEMBER
.n sc4
l.
Y
KR
U.S.
DEPARTMENT OF AGRICULTURE
1978
ex-tent
DISTRIBUTION
The Washington
September
1978
Office has learned
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ENGINEERING
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NOTES
FIELD
Number
10
11
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respon-sibility
Information
of
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contained
United
for
The
the
The
interpretation
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or service
may be
names
text in the
or policy
except
engineers
and engineering
intended
as
FSM
exclusively
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contractors
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and
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own
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or use
of the reader. Such
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and State agencies. The Department
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FOREST SERVICE
U.S.
Field Notes.
DEPARTMENT OF AGRICULTURE
Washington
D.C.
20013
author and
mandatory instructions
publication
all
is
WASHINGTON
OFFICE
NEWS
OPERATIONS
Harold L. Strickland
Assistant Director
Manage-ment
NEW
During
AERIAL
the
past
FIDM and
2
PHOTOGRAPHY
years
FORMAT
Forest
BEING
Insect
EVALUATED
and
TM
Disease
have procured a
Timber Management
significant amount of high-altitude panoramic photography
to
surveys and timber
support multistage insect damage
KA80A
The camera used was an Itek
salvage programs.
with a
bar
camera
24-inch 60.96 cm focal
length optical
The
X
127
cm.
film format of 4-1/4 X 50 inches 10.795
infrared film at a
color
high-resolution
and imagery is taken
theoretical
nadir scale of
of 65000
aircraft at an altitude
from a U-2 reconnaissance
shows
The
drawing
mean sea level
m.s.l..
feet
19812
bar
for one frame of optical
the ground area coverage
and
The camera system and U-2 aircraft are NASA-owned
in
California.
Center
based at NASA Ames Research
camera
system
uses
132500
photog-raphy.
m
Washington Office Engineering has provided technical project
in collection
processing
interpretation and data
support
in the use of the photography.
to assist
transfer activities
Portions of Regions_ l 2 5 and 6 have optical bar coverage.
is in Region
5 which has used
The largest block of coverage
forests.
in more than 13
Approval for this
photography
in a
on the Regions
was contingent
participation
coverage
of
this
to evaluate
the potential
imagery
project
development
Forest Service programs. All
to support multidisciplinary
resource
bar photography
and various
units now using optical
will
5
in the project which
in Region
participate
disciplines
will
be
coordinated
by
Washington
Office
Geometronics.
this imagery requires the
format of
development
unique
and training
support the
photo interpret at ion guidelines
of
evaluation
viewing equipment
requirements to support
and the development
of
photointerpretationactivities
to
transfer techniques
support data measurement
will be
These
areas
addressed
in the
activities.
The
photo-to-map
develop-ment
of
project.
1
awareness
is also being
to make
briefing package
developed
users aware of this technology
potential
and the associated
development
forwarded
to
program.
Copies will be
Regional
Geometronics
Leaders.
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TECHNOLOGICAL
Heyward
Assistant
IMPROVEMENTS
Taylor
Director
T.
FOR
SYSTEM
DESIGN AND MANAGEMENT
SERVICE ROADS - IMPLEMENTATION
PAVEMENT
FOREST
Service-wide
Under the terms of a cooperative
agreement the Forest Service
and the
of
Texas
have
been developing
a
University
for
The
work was
and
pavement design
management.
system
the
divided
into three phases and final reports describing
first two have been distributed Service-wide
under the titles
Phase I - A Pavement Design and Management
System for Forest
Service Roads
A Conceptual
and Phase II 1974
Study
July
A Pavement
and
Forest
Service
Design
Management
System for
A Working
Roads
Model
February 1977.
The
and
phase of the. work has now been completed
report describing the work in Phase III was prepared
and approved
for publication
University
by the Forest
third and final
the
by the
Service.
Man-agement
of the
report Phase III
A Pavement Design and
Forest
Service
Roads
Implementation are
System for
the
and
distribution
to
Forest
by
being
printed
University
is
scheduled
for
Service personnel
January or February.
Copies
per-sonnel
the
project a panel of Forest Service
representing the Regions and the Washington Office
The panel
served
as
a
board for the University.
sounding
to the
input and insight contributing
provided valuable
In
each
phase
of
de-velopment
man-agement
computer-based
program for the design and
surfacing investment on Forest Service roads.
Phase III
four separate training
sessions were held
During
to introduce Forest Service users to the Low Volume Roads
Over 70 Forest Service personnel representing
LVR Program.
30 Forests
and seven Regions
were instructed
in the use
and
of
the
a
This group
operation
represented
program.
of planners engineers
and managers who work in many
different
areas of the country
their response
was that the
and that they the users planned to
program was a good one
use the program more frequently. The Phase III Report
in detail the experience
and reactions of the users the
methodology and the problems encountered the subsequent
modifications to the program are described
in the
final
of
of
a
the
cross-section
docu-ments
report.
3
decisions
and instructions for Service-wide
Management
use
the program are being prepared
and their distribution
for February.
planned
Forest Service personnel who have
for surfacing
and management
design
are urged
read the Phase III report.
of
re-sponsibility
4
is
to
CONSULTATION
Walter
AND
E.
STANDARDS
Furen
AssistantDirector
require-ments
for Forest
We must have trained
Service
qualified
operators
wastewater
treatment
This
has
been the
systems.
certainly
in the past and
with stricter environmental
object
and controls it has become increasingly important.
The
from an editorial by Mr. Martin
paraphrased
Water
Pollution
Control
Federation
Lang
that was published
in Water and Sewage
Works.
We feel this
brief passage
to the need for qualified
speaks very directly
following
is
President-elect
dis-cussions
com-plex
operators.
come to meetings now and they are beginning to
esoteric
jargon
legal talk
legislative
strange
academic
esoteric
discussions and talk about
and new
of
All of them
compounds
techniques
analyses.
But while operators
are increasingly
are getting
important.
with the polysyllabic terminology
of ecology we
comfortable
whole
must not lose sight of the fact that the
water
On top
abatement
program can bea vast inverted pyramid.
are Congressional
legislation EPA rules and regulations and
process designs concrete
steel and equipment
sophisticated
This whole pyramid is
needed to comply with the requirements.
lone operator with an
resting on the back of one individual--a
emergency in a campground treatment plant on a Sunday morning
call on a consultant
of a Fourth of July weekend.
He cant
committee he cant write away to the technology transfer
program and he cant call on some distinguished professor or
EPA official. He must be trained
to do the
right thing.
Therefore the Forest Service must dedicate itself to the
of
the operator
and realize
that the training
of
importance
is as
out
the mean cell
the operator
important as figuring
residence time or knowing
the theoretical kinetics of complete
mixing.
Operators
hear
pollu-tion
The
need for trained
operators
applies equally well to the
of
Forest
Service
This must
potable
operation
water systems.
be emphasized by both line managers
and technical
staff.
S
UNIFIED
ROCK
CLASSIFICATION
SYSTEM
Douglas A. Williamson
Engineering Geologist
Willamette
National
Forest
R-6
origini-naZZy
Unified Rock Classification System URCS was
developed
by Douglas
A.
Williamson in 1959 and 1960.
The system has been used extensively by him and others
on
projects for the U.S. Army Corps of Engineers and the
USDA Forest Service.
The
di-rectives
The
URCS
is
being
system
considered
for publication
Forest Service Handbook.
in
the
classifica-tion
Engi-neering
Readers comments and experiences
send
with rock
URCS
would
be helpful.
Please
systems including
comments
to
the
author
or
to
Jim
Mandigo
your
Staff Unit
WO.
The
Unified
Rock
Classification
allows
rapid
System
URCS
assessments
of
rock
conditions
field
preliminary
by simple
natural
that establish
tests
The
URCS
strength
parameters.
is
all
useful
for
earth-associated
and
construction
design
It
is especially
useful because the pertinent
projects.
natural conditions
related to design
can be read
strengths
at a glance or be confirmed by referring to the original
data base.
In many instances
the data base is too detailed
for collective
analysis.
be-havior.
The
URCS
is
an
engineering
shorthand
used
to
convey
maximum
information.
The URCS classifies rock in simple easily
understood terms that convey evidence of strength and
The
uniform
terms used convey
design
engineers
appeal boards.
meaning
inspectors
to engineering
and
uni-formity
classi-fication
geologists
contract
contractors
Geotechnical
field reports or drill logs sometimes lack a
of notation
to
assure that sufficiently identical
A working
will
be
made
interpretations
by designers.
field
tests which can be
system based on simple
6
uniform-ity.
refined
by laboratory testing can assure this needed
The
URCS is not intended to replace the existing
classification
geologic
engineering
design
The
of
purpose
To
2.
To
a
rather
to
supplement
it
with
parameters.
this paper
present
engineering
1.
but
is
rock classification
system useful for
geology and geotechnical
investigations.
describe a field identification
requires simple field apparatus.
procedure
that
per-mits
3.
the
classifications
establish
design and performance.
To
relationship
to
and
an
indication of rock performance
provides
of
crude estimate
of
the three primary properties
a
permeability and shear strength.
compressive strength
URCS
The
rock
a
classifica-tion
applica-tions
When
as
combined
-
The
with
other
stress history and water
allows a rough estimate
such as
information
geotechnical
table location
the
of
rock
performance
such
for
Foundation
suitablility
Ease or difficulty
of excavation
Slope stability
Suitability for embankments
Suitability for aggregate
Blasting characteristics
Water transmission
it can
will not replace laboratory testing
but
quantity of testing needed and increase the
success by reducing the range of properties that
URCS
reduce the
estima-tion
design
must be assumed.
The
URCS
can be accomplished
by simple field tests or
and testing in a
simplified form or with experience
It
is suitable
determination by
more refined form.
forThe
geotechnical
personnel.
beginning as well as experienced
is
verifiable
and
and
allows
serial
and
reproducible
system
final review by geotechnical
supervisors.
in
a
URCS employs
of
representation
The
sections
the
mind
maps
for graphic
simple system of notation
geotechnical
inventories boring logs
etc.
The
notation
registers rapidly in
a
and minimizes
the
required drafting
7
effort.
UNIFIED
ROCK MASS
ROCK CLASSIFICATION
STRENGTH
ESTIMATE
EFFECT
WEATHERED
SAND
OF WEATHERING
1
SIZE
ALTERED
SIZE
GRAVEL
COMPLETELY
NON
PLASTIC
PLASTIC
VFS
pLASTIC
PLASTIC
FRESH
FRIABLE
CRATERS
SHEARS
E
D
1000 PSI
7 MPa
1000
to
3000
21
PSI
to
to
AND
REBOUNDS
ELASTIC
PITS
TENSIONAL
RO
PQ
C
21
WEIGHT
ABSORPTION
IMPACT
DQ
PLANAR
A
B
8000 PSI
55
MPa
LINEAR
8000
55
to
to
15000
PSI
103 MPa
15000 PSI
103
MPa
ELEMENTS
SOLID-PLANES
TRANSMITS
WATER
NO
YES
DIMENSIONAL
NO
LATENT
DIMENSIONAL
2
3-D
2-D
LPS
SPB
E
D
C
B
SEPARATION
UNIT
LESS
THAN
130
lbs/ft3
Mg/m3
/2.10
E
K.
140
VALUES
and Peck
to
SRB
A
R.
WEIGHT
140
to
150
/2.25
2.40\
ttb
130
D
C
Soil
/1
mechanics
I\
in
to
GREATER
160
M
engineering
8
/2.40
/I
I\
Practice
to
THAN
160 lbs/ft3
lbs/ft3
g/
140
B.
150
lbs/ft3
2.25\
Mt/m3
l
CONSISTENCY
to
lbs/ft3
2.0130
Terzaghi
RANDOM
BREAKAGE
ATTITUDE
INTERLOCK
130
SOLIDPREFERRED
BREAKAGE
PLANES OF
SEPARATION
OF
PLANES
SEPARATION
OF
1
TO
DENTS
3000
MPa
to
7
MFS
BONDING
COMPRESSIVE
CQ
MBL
HAND LENS
UNIT
RELATIVE
STATE
GRAIN
FRESH
STATE
A
TO
REACTION
MOLDABLE
MICRO
B
COMPARE
1
REMOLDING
3
STS
C
NON
MINERAL
YES
STATE
VISUALLY
FRESH
STATE
D
E
REPRESENTATIVE
STAINED
PARTLY
DECOMPOSED
STATE P05
DECOMPOSED
STATE COS
SYSTEM
URCS
BASIC ELEMENTS
-
2.55
2.55\
MI/m3
Mg/m3
71
150
160
B
A
John
Wiley
and
Sons
Inc.
1948.
SYMBOLS
NOTATIONS
AND
classes
can
four-letter
grouped together in
or
on
sections
read at a glance when placed on maps
be
are
and
drilling logs. The four letters are in caps
The letter
denotes that the least design
is required
while
denotes the most design evaluation
made.
in
is required.
means no determination
sequence
value.
estimated
A lower-case
after a letter indicates
The
are
letter
symbols
design
of
a
four
the
major
element
under-lined.
AE
evalua-tion
notation
that
0
e
FIELD NOTATION
In
the
and the
example
The
field the notation includes both the letter symbol
For
abbreviated
basis written under the letter.
classification
Field notebook
BCAD
B
can then
values
The design
for the intended purpose.
1.
DQ
D
130
B--Visual fresh state C--Dents
with hammer blow A--Solid with
random breakage
and D--unit
weight 130 to 140 pcf 2.10 to
2.25 Mg/m3
Explanation
Notes
A
SRB
C
VFS
AAAA requires
established
be
for
this
material
EEEE requires the most
design evaluation.
the
least design
evaluation.
break-age
Some combinations do
completely Decomposed
15000
MPa
103
psi
and Greater than
EAAA.
2.
occur for example
State and Greater than
not
Solid with
160 pcf
random
2.55 Mg/m3
Design values of the four major elements are not
even though the same letter notation
equivalent
might apply.
9
URCS
degree of weathering is restricted to
of weathering
can be
The effect
relative loss of
defined practically
by determining the
Five categories
and the reduction-of unit weight.
cohesion
defined
D--Partly
are
E--Completely Decomposed
State
Under
the
chemical
the
weathering.
State
Decomposed
and A--Micro Fresh
State
C--Stained
State.
EFFECT
1
WEATHERED
SAND
SIZE
PARTLY
DECOMPOSED
STATE CDS
1
VISUALLY
FRESH
STATE
MICRO FRESH
STATE
STS
VFS
MFS
C
B
D
NON
I
PLASTIC
PLASTIC
CONSISTENCY
Terzaghi
K.
VALUES
and
Peck
R.
B.
COMPARE TO
FRESH STATE
NON
PLASTIC
Soil
Mechanics
E--Completely
pgln
Decomposed
State
HAND LENS
UNIT
RELATIVE
in Engineering
77
0%
REPRESENTATIVE
STAINED
STATE
DECOMPOSED
STATE PDS
E
PLASTIC
SIZE
State
WEATHERING
ALTERED
GRAVEL
COMPLETELY
OF
Fresh
B--Visually
Practice
John
Wiley
and
WEIGHT
ABSORPTION
Sons
Inc.
1948.
1%
CDS.
State is when the rock material
Completely Decomposed
all remoldable to sand silt or clay or mixtures of two
The resulting remolded material is determined
or more sizes.
and
and Dry Strength Dilatency
to be plastic
or nonplastic
tests are performed.
The
in-place strength is
Toughness
estimated by consistency values
The
is
1.
D--Partly Decomposed
State
PDS.
deter-mined
1
the rock material is
and larger rock fragments with or
remoldable to gravel-size
The relative percentage
without
sand silt or clay mixtures.
of -rock
fragments are estimated and the material is
The in-place strength is
be plastic
or nonplastic.
to
estimated
values
or by size shape and
by consistency
of remolded aggregate.
graduation
The
Partly Decomposed
C--Stained
State
State
is
when
STS.
The Stained State describes a condition when the rock material
discoloration
due to oxidation but
shows partial or complete
The rock material is usually shades of
be
remolded.
cannot
yellow or brown has a reduced unit weight and a higher
10
compar-ing
of water.
The strength estimate is made by
absorption
State
the Stained
with Fresh State material at a given
area examined.
reduction
is expressed
Weight
as a percentage
of the Fresh State unit weight.
mate-rial
de-sign.
B--Visually
Fresh
State
VFS.
Fresh State
is present
when
the rock material
Visually
of
the
of
representative
standard
quality and not expected
to change within economic
excavation
limits.
The rock
is evaluated
with the naked eye and such an evaluation
is usually
for all foundation
and excavation
acceptable
The rock material has uniform color and is usually
shades of gray green or blue.
The sample tested is
of maximum unit
of weight maximum
specimen
strength
The
is
represen-tative
and
least
Stained
A--Micro
relative
State
Fresh
absorption
are made.
State
from which
sources.
alteration
hand lens.
to
MFS.
The Micro Fresh State is determined
lens.
but
not
It is desirable
determination
comparisons
except
when
making
in
the
field with a hand
to make this
necessary
investigations
for rock
condition
exists when
This
there is no oxidation
of any of the mineral components when viewed with a
11
the
Mineral Grain Bonding
is defined
as
or Specimen Strength
or adhesion between mineral grains that
degree of cementation
defines
the fundamental
strength of the rock mass independent
of
the planar and linear elements.
For purposes of
the limit of moldability is estimated at 1000 psi
7 MPa. There are four distinct reactions to impact loading
The reaction is
ball-peen hammer.
by means of a 1-lb 450-g
of
of
the limitations
independent
intensity of blow within
the tool used and the investigators strength.
The reactions
are
defined
as
and
Rebounds.
Craters Dents
Based on these
reactions
plus the
moldability
factor five
of
are denoted
E--Moldable
categories
specimen
strength
D--Craters C--Dents B--Pits and A--Rebounds.
classifi-cation
Pits
MINERAL
1
REMOLDING
FRIABLE
CRATERS
SHEARS
E
D
1000 PSI
7 MPa
1000
Terzaghi
E--Moldable
K.
VALUES
and Peck
to
7
to
R.
B.
IMPACT
DENTS
DO
PITS
TENSIONAL
REBOUNDS
ELASTIC
B
A
3000
MPa
PSI
soil mechanics
3000
21
in
to
to
8000
55
8000 PSI
55
MPa
Engineering
RO
PQ
C
21
Quality
TO
COMPRESSIVE
CQ
MBL
CONSISTENCY
BONDING
REACTION
MOLDABLE
1
GRAIN
Practice
15000 PSI
103
MPa
to
to
John
Wiley
and
15000
PSI
103 MPa
Sons
Inc.
1948.
MBL.
is present when the otherwise
and
Moldable Quality
continuous
with finger
similar rock
material can be
remolded
visually
an estimated
unconfined
compressive
indicates
pressure. This
estimates
less
than
are
1000
7
MPa.
Strength
strength
psi
made by determining consistency values
In all cases the
material is examined and
is given.
classification
recovered
by
diamond
core
tested
as
Usually
drilling
1.
a
soil
and
a
dual
the material cannot
and can be excavated
be
by
machinery.
D--Crater
Quality
Crater Quality
under
reaction
CQ.
rock material is as the term implies a
a
impact producing
shearing and
point of
has
of
mineral grains.
This
category
upthrusting
adjacent
from
strength
an estimated unconfined
compressive
range
1000 to 3000 psi 7 to 21 MPa.
Usually The rock material
rock
has
core
be
recovered
drilling operations
can
during
12
stresses by
high absorption and will respond to freeze/thaw
and checking.
at least cracking
It has a very low energy
when
transfer
blasted
drained embankments
produces
poorly
and is not suitable for road aggregate material.
C--Dent Quality
DQ.
rock
material produces
a
dent or depression
Quality
of
under the point
It
indicates the presence of
impact.
This category
pore space between the mineral grains.
or quality of material has a estimated unconfined
compressive
and
strength range of 3000 to 8000 psi 21 to 55
is
to the strength
roughly equivalent
range of concrete.
Dent Quality material has low energy transfer in response
to blasting
and often produces a boulders and sand result.
Dent
MPa
B--Pit Quality
Pit Quality
of mineral
a
shallow
PQ.
rock
material
grains under
rough
produces
the point
an
of
explosive departure
impact resulting in
This quality of specimen has an
compressive
strength
range of 8000
pit.
mate-rial.
pro-cedure
estimated
unconfined
A--Rebound
Quality
MPa
and is considered
to
hard rock
15000 psi 55 to 103
Pit Quality rock produces
by the construction
industry.
fill and is suitable for.road aggregate
free-draining
Pit Quality material has high energy transfer in
response to blasting and no special blasting design
is necessary.
Rebound
and is
RQ.
Quality rock material has no reaction to impact
true brittle-elastic
substance
in a mechanical
This quality of specimen strength has an estimated
a
sense.
unconfined
of
than
compressive
strength
greater
15000 psi
Rebound
rock produces
quality
free-draining fill
that is suitable for road aggregate.
this rock
However
material is often
sharp and angular due to its brittleness
and therefore
a
less desirable material.
also
produces
It
has
a very high energy transfer in response
to blasting.
103
MPa.
13
weaknesses
of a rock mass are determined
and
linear features.
Planar separations are
natural
separations
already existing in the rock mass.
Linear features
directional weaknesses
that usually
are
Directional
planar
separa-tion
a
to produce
blasting or mechanical
crushing
Planar and linear elements
are defined
by continuity
relief and shape of the intact rock material between the
The
five
discontinuities.
of
design
categories
decreasing
of
consideration
are
E--Three-Dimensional
Planes
D--Two-Dimensional Planes of Separation C--Latent
and
Planes of
B--Solid-Preferred
Separation
Breakage
require
Separa-tion
A--Solid-Random Breakage.
PLANAR
3
LINEAR
ELEMENTS
SOLID-PLANES
TRANSMITS
YES
AND
NO
WATER
YES
DIMENSIONAL
NO
LATENT
SOLID-
DIMENSIONAL
PLANES
OF
SEPARATION
PLANES
OF
SEPARATION
3_0
2-0
LPS
PREFERRED
BREAKAGE
E
D
C
B
2
OF
SEPARATION
INTERLOCK
SPB
RANDOM
BREAKAGE
SRB
A
ATTITUDE
indi-cates
discon-tinuities
E--Three-Dimensional
The
Planes
three-dimensional
the
presence
passing
examination.
The
of Separation
3-D.
of separation category
or more intersecting planar
through the rock mass at the point
of
planes
two
of
planar separations might form patterns
random in occurrence
thus will form internal
or might be
separations that terminate within the rock mass or will
the
rock
form mass separations
that pass entirely
across
mass and are infinite in extent in terms of design.
By
form a shape.
This shape is
definition three dimensions
founda-tion
joint block
which
has a size and
can be estimated. The degree of
interlock between joint blocks defines the strength of
of
factor.
If
mass planes
or stability of excavation
separation
occur the attitude of the planes with respect to
the
Water
design or slope is the chief design factor.
the planes
of
can be determined
by
along
separation
of
the
or
water
observation
testing.
drilling operation
by
often
weight
referred
to
as
consideration
a
that
trans-missio
14
D--Two-Dimensional
Planes
of Separation
2-D.
examina-tion.
The
the
two-dimensional
of separation
indicates
planes
category
of
series
of
one parallel plane
parallel
presence
or a
planes passing through the rock mass at the point of
The planar separations may vary in frequency but do
not
intersect.
The
attitude
and relief of the planes
are
the fundamental
of
Whether
or
not
elements
design
analysis.
in
the
transmit
water
is
or
determined
as
planes
estimated
class
E.
C--Latent
Planes
LPS.
of Separation
is
Latent Planes of Separation
an
that is between pl-anar and linear.
intermediate
category
The latent planes are
solid rock
an otherwise
lines or lineations in
as
recognized
and
The
might be stronger or weaker than the rock mass.
mass
reaction
of
the
latent plane
to an applied
such
as
a
force
hammer blow will define the strength estimate.
Latent planes
occur in patterns or at random
are continuous
or
the
be
of
measurable
thickness.
In
or
plane may
a
all cases the infilling of the material in the latent plane
of separation is greater than 1000 psi
Latent
MPa.
of
are
not
foundation
separation
usually
a
design
planes
consideration because the material is for all practical
solid. In consideration of slope design or road
a
purposes
aggregate source blasting energy will in most cases be
and directional
reflected
a separation
by the plane producing
or preferred breakage.
discontin-uous
7
SPB.
judg-ing
B--Solid-Preferred
Solid-Preferred
Breakage
Breakage
indicated
when there are no
but
rock breaks along
the
elements
is
visible planar or linear
due to mineral grain alignment
constant angle or direction
a
This
condition
is significant
in
stress.
or internal
of
road
It
is
the
aggregate.
an adverse
production
in some
for the production
of
or
condition
cases
jettystone
stone.
dimension
SRB.
sel-dom
A--Solid-Random
Breakage
This category represents ideal design conditions where
The
there is no effect from planar and linear features.
the
that
the
mass strength
so
specimen strength equals
applies.di-rectly
of
individual
value
strength
any
sample tested
Needless to say
to the mass strength.
this is
in
limited
foundation
dimensions.
achieved
except
very
15
Density or unit wight has been found to be one of the most
reliable means
of
field estimate
of
a
rock quality.
making
It is useful in may ways both in design and construction
The URCS denotes five
planning.
categories of ranges of
130
D--130
to
unit weight
E--Less than
pcf
2.10 Mg/m3
C--140 to 150 pcf
140 pcf
2.10 to 2.25 Mg/m3
2.25 to
B--150 to 160 pcf
2.40 Mg/m3
2.40 to 2.55 Mg/m3 and
A--Greater than 160 pcf 2.55 Mg/m3.
UNIT
LESS
130
THAN
130
lbs/ft3
to
140
140
lbs/ft3
2.10 Mg/m3
2.10
130
\
E
to
WEIGHT
to
150
150
lbs/ft3
2.25
2.25\
Mg/m3
/
to
to
GREATER
160
lbs/ft3
2.40\.
Mg/m3
/I
../2.4
I\
160
2.55
2.55\
to
Mg/m3
THAN
lbs/ft3
Mg/m3
/I
130
140
150
160
D
C
B
A
useful-ness
Unit
Weight-Design
Evaluation.
force
unit weight
determination
establishes
the driving
slope stability problems establishes the relative
of the rock material as a surface course or concrete
aggregate or establishes the weight-volume relationship
for haul
cost
estimates.
As a general
rule-of-thumb rock
is
unit
than
160
a
having
weight greater
pcf 2.55 Mg/m3
The
in
suitable
for
use
as
road
aggregate
concrete
aggregate
riprap or jettystone more than 50 percent of the time
without
Rock with a 150 to 160 pcf 2.40
laboratory
testing.
unit weight may be acceptable
but will require
to 2.55 Mg/m3
with a 150 pcf
for
confirmation.
Rock
testing
laboratory
2.40 Mg/m3 is not usually acceptable for the above purposes
is not free-draining
Rock less than
fill and will degrade.
130 pcf
2.10 Mg/m3 approaches soil in terms of strength
and durability.
Mechan-ics
REFERENCES
1.
D.
F. Classification of Rocks for Rock
International Journal of Rock Mechanics
and Mining
sciences Vol.
pp.
421-429 1964.
Coates
1
2.
Kierch
G.
Larson
D.
of Folsom
3.
and Treasher R. C. Engineering
Geology
Economic Geology Vol. 50 1955.
A.
Dam
A.
Green
1969.
4.
Larson
D.
5.
Larson
D.
Foster
A.
Wynoochee
Foundation
Report
Corps of Engineers
U.S.
1971.
Army
Larson D. A. and Farmer R. D. Blue River Dam
Report U.S. Army Engineer District Portland
Corps
1967.
1970.
Meyers Joseph D.
Show-Low
Highway
101-07
Geologic
U.S.
Arizona
Report McMillanville-Globe
60 Arizona
State
Highway
Materials
Department
Division
1959.
Muller Leopold
Station-Translation
Details
10.
Seattle
Corps
Pub.
9.
Dam
Founda-tion
Founda-tion
of Engineers
8.
Foundation
Report U.S. Army
of
Corps
Engineers 1970.
Dam
Larson D. A. and Farmer R. D. Fall Creek Dam
Report U.S. Army Engineer District Portland
of Engineers
7.
Foundation
Report U.S.
of
Corps
Engineers
Portland
District
Engineer
6.
Dam
Portland
A.
District
Engineer
Peter
District
Army Engineer
Naval
U.S.
Geomechanical
Evaluation
of Petrofabric
Army Engineer Waterways
Experiment
No.
67-10
1958.
Facilities Command Design Manual Soil Mechanics
and Earth Structures NAVFAC DM-7 1962.
Foundation
11.
12.
13.
Shaler S. Design of Rock Slopes Paper
Sponsored
by Committee on Landslide Investigations
National
Research
Board 1962.
Philbrick
Class-ification
H. Discussion of D. F. Coates Rock
International Journal of Rock Mechanics
Mining Sciences and Geomechanics Abstracts Vol. 5
371-373 1968.
pp.
Stapledon
D.
and
Terzaghi K. Section I Rock Defects in Rock Tunneling
with Steel supports by Proctor and White pp. 19-45
Commercial Shearing and Stamping Co. Youngstown
Ohio
1946.
17
14.
15.
16.
Unweath-ered
Engineer-ing
Terzaghi
Stability
Geotechnique
of Steep Slopes in Hard
Vol.
12 pp. 251-270 1962.
Bear-ing
In-vestigation
in
Terzaghi K. and Peck R. B. Soil Mechanics
John Wiley and Sons Inc. 1948.
Practice
H.
and Schumann
E.
H.
R. The Stamp-Load
Strength of Rock An Experimental and Theoretical
Journal of the International
Society for
Wagner
Rock
17.
K.
Rock
mechanics
Williamson
1970.
A. Rock
Classification
for Engineering
Annual
Presented
at
Twentieth
Paper
Investigations
1961
of
the
of
Academy
Science
Meeting
Oregon
D.
is
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