ASTM D7277-08

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Designation: D7277 − 08
StandardTest Method for
Performance Testing of Articulating Concrete Block (ACB)
Revetment Systems for Hydraulic Stability in Open Channel
Flow
This standard is issued under the fixed designation D7277; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D1556 Test Method for Density and Unit Weight of Soil in
Place by Sand-Cone Method
1.1 The purpose of this test method is to provide specifica-
D2216 Test Methods for Laboratory Determination of Water
tions for the hydraulic testing of full-scale articulating concrete
(Moisture) Content of Soil and Rock by Mass
block (ACB) revetment systems under controlled laboratory
D2487 Practice for Classification of Soils for Engineering
conditions for purposes of identifying stability performance in
Purposes (Unified Soil Classification System)
steep slope, high-velocity flows. The testing protocols, includ-
D4318 Test Methods for Liquid Limit, Plastic Limit, and
ing system installation, test procedures, measurement
Plasticity Index of Soils
techniques,analysistechniques,andreportingrequirementsare
D5195 Test Method for Density of Soil and Rock In-Place at
described in this test method.
Depths Below Surface by Nuclear Methods
1.2 The values stated in inch-pound units are to be regarded
as standard. The values given in parentheses are mathematical
3. Terminology
conversions to SI units that are provided for information only
3.1 Definitions:
and are not considered standard.
3.1.1 For common definitions of technical terms in this test
1.2.1 The gravitational system of inch-pound units is used
method, refer to Terminology D653.
when dealing with inch-pound units. In this system, the pound
3.1.2 articulating concrete block (ACB) revetment system,
(lbf) represents a unit of force (weight), while the unit for mass
n—in erosion control, a matrix of interconnected concrete
is slugs.The rationalized slug unit is not given, unless dynamic
block units for erosion protection. Units are typically con-
(F = ma) calculations are involved.
nected by geometric interlock, cables, ropes, geotextile,
1.3 This standard does not purport to address all of the
geogrids or a combination thereof and typically include a
safety concerns, if any, associated with its use. It is the
geotextile underlayment.
responsibility of the user of this standard to establish appro-
3.1.3 depth of flow, y , (L), n—in hydraulics, the distance
o
priate safety and health practices and determine the applica-
from the channel thalweg to the water surface, measured
bility of regulatory limitations prior to use.
normal to the direction of flow, for a given discharge.
3 –1
2. Referenced Documents
3.1.4 design discharge, Q , (L T ), n—in erosion control,
d
2.1 ASTM Standards: the volumetric quantity of water flow within a channel which
is typically used in determining required channel dimensions
D422 Test Method for Particle-Size Analysis of Soils
D653 Terminology Relating to Soil, Rock, and Contained and suitable lining materials for ensuring adequate channel
capacity and stability.
Fluids
D698 Test Methods for Laboratory Compaction Character- 3.1.4.1 Discussion—The discharge associated with a speci-
istics of Soil Using Standard Effort (12 400 ft-lbf/ft (600 fied frequency of recurrence, for example, an n-year flood.The
kN-m/m )) n-year flood event has a probability of 1/n of being equaled or
exceeded in any given year.
3 –1
This guide is under the jurisdiction ofASTM Committee D18 on Soil and Rock 3.1.5 discharge, Q, (L T ), n—in channel flow, the volume
and is the direct responsibility of Subcommittee D18.25 on Erosion and Sediment
of water flowing through a cross-section in a unit of time,
Control Technology.
including sediment or other solids that may be dissolved in or
Current edition approved Aug. 1, 2008. Published September 2008. DOI:
mixed with the water; usually cubic feet per second (ft /s) or
10.1520/D7277-08.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
cubic meters per second (m /s).
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
3.1.6 hydraulic radius, (L), n—in channel flow, the cross-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. sectional area of flow divided by the wetted perimeter.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7277 − 08
3 –1
3.1.7 local velocity, (L T ), n—in channel flow, the veloc- definition does not restrict or limit the block size, shape,
ity at a specific point in the flow region. May be defined as a strength, or longevity; however, guidelines and recommenda-
direction-dependent quantity with components V , V,or V . tions regarding these factors are incorporated into this stan-
x y z
–1
dard. Blocks are available in either open-cell or closed-cell
3.1.8 mean velocity, (LT ), n—in hydraulics, the average
configurations.
velocity throughout a channel cross section. Defined as the
discharge divided by the cross-sectional area of flow usually
6. Preparation of Test Section
expressed in meters per second (m/s) or feet per second (ft/s).
–1
6.1 Soil Subgrade Construction:
3.1.9 subcritical flow, (LT ), n—in channel flow, a charac-
6.1.1 The testing program includes the construction of an
teristic of flowing water whereby gravitational forces dominate
earthen test subgrade compacted between vertical walls of the
over inertial forces, quantified by a Froude Number less than 1.
–1 testing flume (Fig. 1). The soil subgrade shall be placed and
3.1.10 supercritical flow, (LT ), n—in channel flow,a
compacted in horizontal lifts of 4 to 6 in. (100 to 150 mm) in
characteristic of flowing water whereby inertial forces domi-
thicknesstoaminimumsubgradethicknessof12in.(300mm).
nate over gravitational forces, quantified by a Froude Number
The distance between the walls shall be a minimum of 4.0 ft
greater than 1.
(1.2 m); installation shall be reflective of standard field usage
–1
3.1.11 uniform flow, (LT ), n—in hydraulics, the condition
and shall accommodate full-scale block units such that at least
of flow where the rate of energy loss due to frictional and form
one block is not adjacent to a sidewall, at least every other row
resistance is equal to the bed slope of the channel.
of the revetment matrix.
3.1.11.1 Discussion—Where uniform flow exists, the slopes
6.1.2 The soil subgrade shall consist of a silty sand with a
of the energy grade line, the water surface, and the channel bed
plasticity index (PI) in the range of 2 to 6 %, and will be
are identical. Cross-sectional area and velocity of flow do not
compacted at optimum water content to between 90 and 95 %
change from cross section to cross section in uniform flow.
of Standard Effort density (Test Methods D698). The embank-
–1
3.1.12 velocity, V, (LT ), n—in channel flow, time rate of
ment shall be constructed to a height such that the finished
linear motion in a given direction.
surfaceoftherevetmentconsistsofahorizontalcrestsectionat
least 6 ft (1.8 m) in length followed by a downstream slope
4. Summary of Test Method
angle typically set at 2H:1V.
4.1 The test method is designed to determine the stability
NOTE 1—Test conditions may incorporate slopes other that the 2H:1V
threshold values of shear stress and velocity of articulating
identified as the benchmark. Variations from the procedures identified
must be included in the report. Additionally, engineering judgment must
concrete block (ACB) revetment systems under controlled
accompany utilizing and interpreting the results from tests varying from
laboratory conditions of steep-slope, high-velocity flow (flume
the proposed test method.
test). Systems are tested as full-scale production units.
6.1.3 Soil information to be determined and documented
4.2 The procedures associated with test set-up, testing, data
prior to and during test embankment construction includes, as
collection, and reporting are provided in this test method.
applicable:
6.1.3.1 Standard Effort moisture-density curve, Test Meth-
5. Significance and Use
ods D698.
5.1 An articulating concrete block revetment system is
6.1.3.2 Soil textural classification, Practice D2487.
comprised of a matrix of individual concrete blocks placed
6.1.3.3 Particle size distribution curve (including hydrom-
together to form an erosion-resistant revetment with specific
eter fraction), Test Method D422, and
hydraulic performance characteristics. The system includes a
6.1.3.4 Atterberg Limits (liquid limit, plastic limit), Test
filterlayercompatiblewiththesubsoilwhichallowsinfiltration
Methods D4318.
and exfiltration to occur while providing particle retention.The
6.1.4 Following the preparation of the soil subgrade, the
filter layer may be comprised of a geotextile, properly graded
following information is determined within 24 h prior to
granular media, or both. The concrete blocks within the matrix
installation of the revetment system. This information shall
shall be dense and durable, and the matrix shall be flexible and
include as a minimum the soil water (moisture) content (Test
porous.
Methods D2216) and density/unit weight determined by sand
5.2 ACB revetment system are used to provide erosion cone (Test Method D1556) or nuclear gauge (Test Method
protection to underlying soil materials from the forces of D5195) at a minimum of two locations along the centerline of
flowing water.The term “articulating,” as used in this standard, the test embankment.
implies the ability of individual concrete blocks of the system
6.2 Installation of ACB Revetment System:
to conform to changes in subgrade while remaining intercon-
6.2.1 A properly designed filter (geotextile, granular filter,
nected by virtue of geometric interlock, cables, ropes,
or both), properly engineered or selected for the soil subgrade
geotextiles, geogrids, or combination thereof.
utilized for testing, and the ACBs shall be placed on the crest
5.3 The definition of ACB revetment system does not and downstream slope in accordance with the manufacturer’s
distinguish between interlocking and non-interlocking block recommendations.Potentialartificiallyinducedscouralongthe
geometries, between cable-tied and non-cable-tied systems, sidewalls will be prevented by placing geotextile wadding,
between vegetated and non-vegetated systems or between protective flashing, loose grout or a combination, along the
methods of manufacturing or placement. Furthermore, the edge of the ACB revetment system (Fig. 2). The chosen side
D7277 − 08
NOTE 1—Drawing not to scale, and slope, as shown, is not 2H:1V.
NOTE 2—1 ft = 0.305 m.
FIG. 1 Schematic Profile of Typical Testing Flume
FIG. 2 Recommended Sidewall Detail (Cross Section View)
protection shall allow nominal block movement and not press Horizontal projection of the side protection shall extend a
the block onto the subgrade. Side protection shall permit a gap minimum of 0.5 in. (13 mm) and a maximum of 2.5 in. (64
a above the blocks a minimum of 0.25 in. (6.4 mm) and a mm) into the flume. The ACB revetment system will be
maximum of 0.75 in. (19 mm) in the vertical direction. secured at the embankment toe by means of a bolted or welded
D7277 − 08
toe retention system designed for the specific system to be Typically, target discharges correspond to predetermined over-
tested (Fig. 3). Depending on the geometry of the system being topping depths above the revetment system’s crest elevation
tested, void spaces next to the sidewalls greater than 3 in. (75
(for example, 1 ft (0.3 m), 2 ft (0.6 m), etc.), although any
mm) should be filled with partial blocks specially cut with a
discharge may be utilized provided proper measurement and
masonry saw to fill the void, while maintaining the proper
reporting procedures are followed as described in this docu-
geometric relationship of the matrix. Under no circumstances
ment. Even if minor system deformation occurs during the test,
should the void spaces against the sidewall be filled any
hourly data collection shall be maintained for the entire
compound that bonds the block to the sidewall or prevents the
four-hour test duration, unless catastrophic ACB revetment
system from its inherent ability to articulate. As shown in Fig.
system failure occurs.
1, a joint between theACBs shall occur at the crest (top) of the
7.2 Water Surface and Bed Elevation Profiles—Hourlymea-
slope.
surements of water surface elevation will be made at 2-ft
7. Procedure
(0.6-m) intervals (stations) along the centerline of the embank-
ment during each test. Bed elevations (top of ACB revetment
7.1 Definition of Test—A test consists of a continuous
surface) shall be established prior to each test and again after
four-hour flow over the ACB revetment system at a uniform
the cessation of each test, at the same measurement stations as
discharge. Providing that the ACB revetment system success-
the water surface readings. When testing ACBs that exhibit a
fully survives the four-hour flow without deformation, soil
staggered layout pattern such that there may not be a block at
loss, or loss of solid contact with the soil subgrade, the
the centerline location at every measurement station, an adja-
procedure is repeated at the next higher target discharge or
until the flow capacity of the testing facility is reached. cent block to the left or right of the centerline may be selected
FIG. 3 Recommended Toe Detail Options (Profile View)
D7277 − 08
as the measurement point. Those ACBs should be identified 8.2.2.1 Section-average velocity, V , is computed as the
ave
with a paint mark to ensure consistency in measurement. best value of Q (determined above) divided by the cross-
r
Measurements should be made to the nearest 0.01 ft (0.003 m) sectional area A, normal to the ACB surface.
using point gauge, survey level, or other suitable elevation-
8.2.2.2 Flow depth, y , is computed as the difference in the
measuring device. Suitable stationing positions should be measured centerline water surface elevation (WSEL) and the
establishedsothatthehorizontallocationofeachmeasurement
elevation of the ACB surface, corrected for the slope angle as
station does not vary between subsequent measurements. appropriate,ateachmeasurementstation.Flowdepthsaretobe
reported as being collected either normal, or vertical in
7.3 Water Velocity Measurements—Hourlymeasurementsof
reference
...