ASTM D7276-16(2023)
(Guide)Standard Guide for Analysis and Interpretation of Test Data for Articulating Concrete Block (ACB) Revetment Systems in Open Channel Flow
Standard Guide for Analysis and Interpretation of Test Data for Articulating Concrete Block (ACB) Revetment Systems in Open Channel Flow
SIGNIFICANCE AND USE
5.1 This standard is intended for use by researchers and designers to assess the stability of articulating concrete block (ACB) revetment systems in order to achieve stable hydraulic performance under the erosive force of flowing water.
5.2 An articulating concrete block system is comprised of a matrix of individual concrete blocks placed together to form an erosion-resistant revetment with specific hydraulic performance characteristics. The system includes a filter layer compatible with the subsoil which allows infiltration and exfiltration to occur while providing particle retention. The filter layer may be comprised of a geotextile, properly graded granular media, or both. The blocks within the matrix shall be dense and durable, and the matrix shall be flexible and porous.
5.3 Articulating concrete block systems are used to provide erosion protection to underlying soil materials from the forces of flowing water. The term “articulating,” as used in this standard, implies the ability of individual blocks of the system to conform to changes in the subgrade while remaining interconnected by virtue of block interlock or additional system components such as cables, ropes, geotextiles, geogrids, or other connecting devices, or combinations thereof.
5.4 The definition of articulating concrete block systems does not distinguish between interlocking and non-interlocking block geometries, between cable-tied and non-cable-tied systems, between vegetated and non-vegetated systems or between methods of manufacturing or placement. This standard does not specify size restrictions for individual block units. Block systems are available in either open-cell or closed-cell varieties.
SCOPE
1.1 The purpose of this guide is to provide recommended guidelines for the analysis and interpretation of hydraulic test data for articulating concrete block (ACB) revetment systems under steep slope, high velocity flow conditions in a rectangular open channel. Data from tests performed under controlled laboratory conditions are used to quantify stability performance of ACB systems under hydraulic loading. This guide is intended to be used in conjunction with Test Method D7277.
1.2 This guide offers an organized collection of information or a series of options and does not recommend a specific course of action. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which adequacy of a given professional service must be judged, nor can this document be applied without considerations of a project’s many unique aspects. The word “Standard” in the title of this document means only that the document has been approved through the ASTM consensus process.
1.3 The values stated in inch-pound units are to be regarded as standard. The user of the standard is responsible for any and all conversions to other systems of units. Reporting of test results in units other than inch-pound shall not be regarded as nonconformance with this test method.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7276 − 16 (Reapproved 2023)
Standard Guide for
Analysis and Interpretation of Test Data for Articulating
Concrete Block (ACB) Revetment Systems in Open Channel
Flow
This standard is issued under the fixed designation D7276; 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 ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
1.1 The purpose of this guide is to provide recommended
mendations issued by the World Trade Organization Technical
guidelines for the analysis and interpretation of hydraulic test
Barriers to Trade (TBT) Committee.
data for articulating concrete block (ACB) revetment systems
under steep slope, high velocity flow conditions in a rectangu-
2. Referenced Documents
lar open channel. Data from tests performed under controlled
laboratory conditions are used to quantify stability perfor-
2.1 ASTM Standards:
mance of ACB systems under hydraulic loading. This guide is
D653 Terminology Relating to Soil, Rock, and Contained
intended to be used in conjunction with Test Method D7277.
Fluids
D6026 Practice for Using Significant Digits and Data Re-
1.2 This guide offers an organized collection of information
cords in Geotechnical Data
or a series of options and does not recommend a specific course
D6684 Specification for Materials and Manufacture of Ar-
of action. This document cannot replace education or experi-
ticulating Concrete Block (ACB) Systems
ence and should be used in conjunction with professional
D6884 Practice for Installation of Articulating Concrete
judgment. Not all aspects of this guide may be applicable in all
Block (ACB) Revetment Systems
circumstances. This ASTM standard is not intended to repre-
D7277 Test Method for Performance Testing of Articulating
sent or replace the standard of care by which adequacy of a
Concrete Block (ACB) Revetment Systems for Hydraulic
given professional service must be judged, nor can this
Stability in Open Channel Flow
document be applied without considerations of a project’s
many unique aspects. The word “Standard” in the title of this
3. Terminology
document means only that the document has been approved
through the ASTM consensus process.
3.1 For definitions of common terms used in this standard,
see Terminology D653.
1.3 The values stated in inch-pound units are to be regarded
as standard. The user of the standard is responsible for any and
4. Summary of Guide
all conversions to other systems of units. Reporting of test
results in units other than inch-pound shall not be regarded as
4.1 The analysis and interpretation of data from hydraulic
nonconformance with this test method.
tests of articulating concrete block (ACB) revetment systems is
1.4 This standard does not purport to address all of the
essential to the selection and design of a suitable system for a
safety concerns, if any, associated with its use. It is the
specific application. This guide provides guidelines for assist-
responsibility of the user of this standard to establish appro-
ing designers and specifiers in developing a correspondence
priate safety, health, and environmental practices and deter-
between the test data and the stability parameters used for
mine the applicability of regulatory limitations prior to use.
design.
1.5 This international standard was developed in accor-
4.2 This standard addresses the analysis of hydraulic test
dance with internationally recognized principles on standard-
data that is generated from a test or series of tests conducted in
accordance with Test Method D7277.
This guide is under the jurisdiction of ASTM Committee D18 on Soil and Rock
and is the direct responsibility of Subcommittee D18.25 on Erosion and Sediment
Control Technology. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Aug. 1, 2023. Published August 2023. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2008. Last previous edition approved in 2016 as D7276 - 16. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D7276-16R23. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7276 − 16 (2023)
5. Significance and Use means for delivering water to the test section. Alternatively, the
discharge may be computed at each of the measurement
5.1 This standard is intended for use by researchers and
cross-sections by the continuity equation:
designers to assess the stability of articulating concrete block
Q 5 A V (1)
(ACB) revetment systems in order to achieve stable hydraulic ~ !
0.6
performance under the erosive force of flowing water.
where:
5.2 An articulating concrete block system is comprised of a
V = centerline point velocity at six-tenths of the depth of
0.6
matrix of individual concrete blocks placed together to form an
flow at each station, ft/s, (L/T), and
erosion-resistant revetment with specific hydraulic perfor-
A = the cross-sectional area of flow at the same station,
mance characteristics. The system includes a filter layer
measured perpendicular to the direction of flow,
2 2
compatible with the subsoil which allows infiltration and
ft (L ).
exfiltration to occur while providing particle retention. The
6.2.2.1 The accuracy of the discharge measurement shall be
filter layer may be comprised of a geotextile, properly graded
reported as described in Section 7 of this standard.
granular media, or both. The blocks within the matrix shall be
6.2.3 Flow Depth, y, is computed as the difference in the
dense and durable, and the matrix shall be flexible and porous.
measured centerline water surface elevation and the elevation
5.3 Articulating concrete block systems are used to provide
of the revetment surface, corrected for the slope angle θ as
erosion protection to underlying soil materials from the forces
appropriate, at each measurement station:
of flowing water. The term “articulating,” as used in this
y 5 h 2 z cosθ (2)
standard, implies the ability of individual blocks of the system ~ !
i i i
to conform to changes in the subgrade while remaining
where:
interconnected by virtue of block interlock or additional system
y = depth of flow at station i (perpendicular to the bed), ft
i
components such as cables, ropes, geotextiles, geogrids, or
(L),
other connecting devices, or combinations thereof.
h = water surface elevation at station i, ft (L),
i
5.4 The definition of articulating concrete block systems z = bed elevation (top of blocks) at station i, ft (L), and
i
does not distinguish between interlocking and non-interlocking θ = slope angle measured from the horizontal.
block geometries, between cable-tied and non-cable-tied
6.2.4 Energy Grade Slope, S , at each measurement station
f
systems, between vegetated and non-vegetated systems or
is calculated from other measured or computed variables as:
between methods of manufacturing or placement. This stan-
n V 1
~ !
dard does not specify size restrictions for individual block i
S 5 (3)
F G
fi 4/3
K y
units. Block systems are available in either open-cell or u i
closed-cell varieties.
where:
S = slope of the energy grade line at station i, ft/ft (L/L),
6. Procedure fi
n = Manning’s resistance coefficient,
6.1 Data Analysis:
V = velocity at station i, ft/s (L/T), and
i
6.1.1 This section describes the analysis and interpretation
K = units conversion coefficient, equal to 1.486 for U.S.
u
of the data collected during a test, including the determination
Customary Units and 1.0 for SI Units.
of hydraulic conditions, qualitative observations and descrip-
6.2.4.1 Eq 3 assumes that the flume walls are significantly
tions of any damage to the revetment system, and quantifica-
smoother than the revetment surface, such that the total
tion of threshold hydraulic stability values resulting from this
resistance is due solely to the roughness of the bed.
analysis that are characteristic of the tested system.
6.2.5 Step-Forewater Analysis—Knowing the total dis-
6.1.2 Typical test environments incorporate a flow regime
charge Q, flume width b, and the elevations of the water
that is supercritical, characterized by high velocities with
surface and revetment surface at each of the measurement
relatively shallow depths of flow. In supercritical flow, small
stations, a forewater calculation can be performed to obtain the
variations in measured depth can result in relatively large
optimal value of the Manning’s n coefficient.
variations in calculated energy and shear stress. The analytical
methods suggested in this section have been selected based on
6.2.5.1 For supercritical flow, it is recommended that the
their suitability to analyze these hydraulic conditions. water surface profile be computed by solving the momentum
equation using the standard step method and proceeding in the
6.2 Hydraulic Conditions:
downstream direction:
6.2.1 Accurately quantifying the hydraulic conditions that
existed during the test is fundamental to the establishment of
1 L
h 5 h 1 v 1v v 2 v 2 S 1S (4)
~ ! ~ ! ~ !
2 1 1 2 1 2 f1 f2
stability performance thresholds. The important hydraulic vari- 2g 2
ables that characterize open channel flow include total dis-
where:
charge Q, section-averaged velocity V, flow depth y, slope of
h , h = upstream and downstream water surface eleva-
1 2
the energy grade line S , resistance coefficient (for example,
f
tions at stations 1 and 2, ft (L),
Manning n-value), and boundary shear stress τ.
v , v = upstream and downstream velocity at stations 1
1 2
6.2.2 Total Discharge, Q, is determined by use of a primary
and 2, ft/s (L/T),
flow measurement device such as an in-line flow meter, weir,
Ls = slope length between stations 1 and 2, ft (L), and
Parshall flume, or other device appropriate to the facility’s
D7276 − 16 (2023)
representative depth associated with that determination.
S , S = upstream and downstream energy grade slopes at
f1 f2
Typically, a linear regression is performed to determine the
stations 1 and 2 as defined by Eq 3, ft/ft (L/L).
slope of the energy grade line. The measured depths from the
NOTE 1—Other numerical methods are available for computing the
water surface profile, for example the direct step method. The standard
stations used in this regression analysis are averaged to
step method is being recommended here because it allows computation of
determine the representative depth y in order to calculate the
hydraulic conditions at the actual locations of the flume measurement
bed shear stress.
stations.
6.2.8.2 Alternatively, the momentum equation across a rep-
6.2.5.2 The objective function to be minimized is defined
resentative control volume of finite length L may be used to
as:
calculate τ :
i
n
ξ 5 abs h 2 h (5)
~ !
pred obs
( γ 1 γ 1 1
i5i 2 2 2
τ 5 y 1y sinθ1 y 2 y cosθ 2 ρq 2 (8)
~ ! F ~ ! S DG
0 1 2 1 2
2 L 2 y y
2 1
where:
where:
i = beginning station for analysis,
3 3
γ = unit weight of water, 62.4 lb/ft (M ⁄L ),
i = ending station for analysis,
n
y , y = flow depths at the upstream and downstream ends of
h = predicted water surface elevation at station i , ft (L),
1 2
pred i
the control volume, respectively, ft (L),
and
v , v = flow velocity at the upstream and downstream ends
h = observed water surface elevation at station i , ft (L).
1 2
obs i
of the control volume, respectively, ft/s (L/T),
6.2.5.3 By examining a range of Manning’s n values, the
L = length of the control volume along the slope, ft (L),
optimal Manning’s n is identified as that which yields the 3 3
ρ = unit mass of water, 1.94 slugs/ft (M ⁄L ), and
3 3
minimum value of the objective function defined by Eq 5. The
q = unit discharge, ft /s per foot width (L /T per L
optimal Mannings n value is then used to calculate the water
width).
surface elevation that best fits the observed data. An example
6.2.8.3 Both methods given above for quantifying shear
of such a forewater calculation is provided in Appendix X1.
stress depend on the judgment of the practitioner to define the
6.2.6 Section-Average Velocity, V , is computed as dis-
ave
data that best represents the stable performance of the block
charge Q (determined above) divided by the cross-sectional
area A, normal to the embankment surface, at each measure- system. In practice, many data sets will include one or more
ment station along the test section. points where the energy grade is not consistent with the
6.2.7 Energy Grade Line Elevation, EGL, is determined at expected trend. In most cases, outliers can be most readily
each measurement station by the following equation: identified by plotting the elevation of the energy line versus
2 distance along the embankment. Note that when Eq 8 is used,
~V !
i
EGL 5 z 1y cos θ 1 (6)
~ !
i i i the x-axis plotting position for the calculated shear stress τ is
2g
located halfway between stations 1 and 2.
where:
6.2.8.4 Appendix X1 provides an example of such a plot,
EGL = elevation of the energy grade line at station i, ft (L),
i
and illustrates the use of the step-forewater analysis procedure
and
2 2 to quantify the hydraulic conditions in areas where data
g = gravitational constant, 32.2 ft/s (L ⁄T ).
variability exists. Fig. 1 provides a definition sketch for the
6.2.7.1 The procedure for determining energy slope should
variables presented in this section.
be performed for the data representing the flow field on the
6.3 Qualitative Observations of Stability:
downstream slope of the test section. If a measurement station
happens to coincide with the point of the break in slope, data
6.3.1 The hydraulic conditions at the threshold of failure
from that station should not be used because of the severe flow
determine the hydraulic stability parameters that characterize
curvature at that location.
the revetment system’s performance. Both shear stress and
6.2.8 Shear Stress, τ —If gradually varied flow character-
velocity at the threshold of failure are typically used for
izes the flow field, the maximum boundary shear stress at the
purposes of developing selection and design criteria for a
bed, τ , is determined from measured or calculated variables
0 particular block system.
as:
6.3.2 The researcher’s determination of “failure” of a revet-
τ 5 γ~y! ~S ! (7)
ment system during a test is somewhat subjective, and
...
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