ASTM D2573/D2573M-18

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
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Designation: D2573/D2573M − 15 D2573/D2573M − 18
Standard Test Method for
Field Vane Shear Test in Saturated Fine-Grained Soils
This standard is issued under the fixed designation D2573/D2573M; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
ε NOTE—Editorially corrected Eq 1 and 2 in February 2018.
1. Scope*
1.1 This test method covers the field vane test in saturated clay and silt soils for determination of undrained shear strength.
Knowledge of the nature of the soil in which each vane test is to be made is necessary for assessment of the applicability and
interpretation of the test. The test is not applicable for sandy soils or non-plastic silts, which may allow drainage during the test.
1.2 This test method addresses testing on land and for testing in drill holes or by self-drilling or continuous push methods from
the ground surface. This method does not address specifically marine testing where special test requirements or variations in
equipment may be required. The user is referred to ASTM STP 1014 for additional information on in-place vane shear testing used
in marine exploration.
1.3 This method is often used in conjunction with fluid rotary drilling (D5783), hollow-stem augers (D6151D6151/D6151M),
or cone penetration testing (D5778). Some apparatuses have the vane retracted in a protective shoe for advancement and
incremental testing. Sampling, such as with thin wall tubes (D1587D1587/D1587M) is often combined with vane testing.
Subsurface geotechnical explorations are reported in accordance with Practice (D5434).
1.4 Undrained shear strength and sensitivity of cohesive soils can also be measured in Laboratory Vane Test (D4648D4648/
D4648M).
1.5 Units—The values stated in either SI units or inch-pound units [presented in brackets] are to be regarded separately as
standard. The values in each system may not be exact equivalents; therefore, each system shall be used independently of the other.
Combining values from the two systems may result in non-conformance with the standard. Reporting of test results in units other
than SI shall not be regarded as nonconformance with this test method.
1.5.1 The gravitational system of inch-pound units is used when dealing with inch-pound units. In this system, the pound (lbf)
represents a unit of force (weight), while the unit for mass is slugs. The rationalized slug unit is not given, unless dynamic (F =
ma) calculations are involved.
1.6 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice
D6026.
1.6.1 The procedures used to specify how data are collected/ recorded or calculated in this standard are regarded as the industry
standard. In addition they are representative of the significant digits that generally should be retained. The procedures used do not
consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives,
and it is common practice to increase or reduce significant digits or reported data to be commensurate with these considerations.
It is beyond the scope of this standard to consider significant digits used in analytical methods for engineering design.
1.7 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.
1.8 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.
This test method is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.02 on Sampling and Related
Field Testing for Soil Evaluations.
Current edition approved July 1, 2015Dec. 1, 2018. Published July 2015December 2018. Originally approved in 1967. Last previous edition approved in 20082015 as
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D2573 – 08.D2573/D2573M – 15 . DOI: 10.1520/D2573_D2573M-15E01.10.1520/D2573_D2573M-18.
ASTM STP 1014 on Vane Shear Strength Testing in Soils (1988).
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2573/D2573M − 18
2. Referenced Documents
2.1 ASTM Standards:
D653 Terminology Relating to Soil, Rock, and Contained Fluids
D1587D1587/D1587M Practice for Thin-Walled Tube Sampling of Fine-Grained Soils for Geotechnical Purposes
D2166D2166/D2166M Test Method for Unconfined Compressive Strength of Cohesive Soil
D2488 Practice for Description and Identification of Soils (Visual-Manual Procedures)
D2850 Test Method for Unconsolidated-Undrained Triaxial Compression Test on Cohesive Soils
D3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in
Engineering Design and Construction
D4648D4648/D4648M Test Methods for Laboratory Miniature Vane Shear Test for SaturatedFine-Grained Clayey Soil
D5434 Guide for Field Logging of Subsurface Explorations of Soil and Rock
D5778 Test Method for Electronic Friction Cone and Piezocone Penetration Testing of Soils
D5783 Guide for Use of Direct Rotary Drilling with Water-Based Drilling Fluid for Geoenvironmental Exploration and the
Installation of Subsurface Water-Quality Monitoring Devices
D6026 Practice for Using Significant Digits in Geotechnical Data
D6151D6151/D6151M Practice for Using Hollow-Stem Augers for Geotechnical Exploration and Soil Sampling
2.2 Other Standards:
Recommended Standard for Field Vane Shear Test, Swedish Geotechnical Society, SGF Report 2:93E, Swedish Geotechnical
Institute, Linköping: www.swedgeo.se
EuroCode 7: Geotechnical Design–Part 3 Design Assisted by Field Testing, ENV 1997-3:1999E, CEN
3. Terminology
3.1 Definitions:
3.1.1 For common definitions of terms in this standard, refer to Terminology D653.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 remolded undrained shear strength—shear strength of fine-grained soil in rapid loading with essentially no drainage of
pore water pressure after significant failure and remolding of the initial soil structure. (Also see D2850 and D4648D4648/
D4648M).
3.2.2 undrained shear strength—shear strength of fine-grained soil (primarily clays and plastic silts) in rapid loading with
essentially no drainage of porewater pressure. (Also see D2850 and D4648D4648/D4648M).
3.2.3 vane—a device with four, thin, flat metal blades or plates, fixed at an angle of 90 degrees to each other, which is inserted
into the soil and then rotated about a vertical axis for shear testing (see Fig. 1).
3.2.4 vane shoe—a section of casing and cutting bit at the end in which the vane can be retracted while drilling or pushing
3.3 Symbols Specific to This Standard:
3.3.1 (s ) —the peak undrained shearing resistance measured during the initial rotation of the vane in a vane shear test.
u fv
3.3.2 (s ) —the remolded undrained shear strength is measured after five to ten vane rotations in a vane shear test.
ur fv
3.3.3 S —the ratio of peak undrained shear strength to remolded undrained shear strength measured in the field vane shear
T fv
test: S = (s )f /(s )f . The remolded shear strength is measured after large shearing strains (see 8.7 and 9.2).
T fv u v ur v
FIG. 1 Geometry of Field Vanes
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
D2573/D2573M − 18
NOTE 1—Previous and existing standards have specified different amounts of rotation, from 5 to 25 revolutions, for measurement of remolded strength.
If sensitivity is reported, the number of revolutions must also be reported. Sensitivity can also be measured in unconfined compression testing
(D2166D2166/D2166M) and laboratory vane testing (D4648D4648/D4648M).
3.3.4 T, (FL)—the measured torque required to rotate the vane.
3.3.5 T , (FL)—the measured residual torque required to rotate the vane after rotating the vane for 5 to 10 revolutions.
R
3.3.6 V –%—the ratio of the cross section area of the vane to the circular area of the rotated vane expressed as a percent (see
A
Fig. 2).
3.4 Abbreviations Specific to This Standard:
3.4.1 VST—vane shear test.
3.4.2 FV—field vane.
4. Summary of Test Method
4.1 The vane shear test consists of placing a four-bladed vane in the intact soil and rotating it from the surface to determine the
torque required to shear a cylindrical surface with the vane. This torque, or moment, is then converted to a unit shearing resistance
of the failure surface by limit equilibrium analysis. Friction of the vane rod and instrument are either minimized during readings
by special casings or housing, or else accounted for and subtracted from the total torque to determine the torque applied to the vane.
5. Significance and Use
5.1 This test method provides an indication of in-situ undrained shear strength of saturated fine-grained soils (clays and silts)
or other saturated fine-grained geomaterials, such as mine tailings and organic muck. The test is applicable to soils with undrained
strengths of less than 200 kPa [2 tsf]. Very sensitive soils can be remolded during vane insertion.
5.2 This test method is used extensively in a variety of geotechnical explorations to evaluate rapid loading strength for total
stress analysis of saturated fine-grained clays and silts. Since vane shear strength values are most always higher than field strengths
for analyses (5.3) they often are checked or compared with other methods of measuring undrained shear strength. Cone
Penetrometer Tests (Test Method D5778) and Unconsolidated Undrained Triaxial Compression (D2850) tests are most often
performed for direct comparison to the vane shear strength data. Unconfined Compression (D2166D2166/D2166M) testing could
also be performed, but suffers from many possible errors from disturbance especially in fissured clays, and should only be
performed with experience. For more information on how these tests are used for soft ground site exploration refer to Ladd and
DeGroot.(1)
FIG. 2 Definition of Vane Area Ratio (ASTM D4648D4648/D4648M)
(Note, r is radius of central shaft).
The boldface numbers in parentheses refer to a list of references at the end of this standard.
D2573/D2573M − 18
5.3 The peak undrained shear resistance of the vane test is commonly corrected to determine the undrained shear strength for
geotechnical analysis. The agency requesting the testing must interpret these data to determine applicability for strength analysis.
It is beyond the scope of this standard to recommend applicability of vane testing for geotechnical analysis. For information on
the general use of these correction factors, consult Appendix X1.
5.4 This method is not applicable in unsaturated soils or in non-plastic silts, sands, gravels, or other high permeability soils. With
the shearing rates described in this standard, sand lenses, if present, will allow total or partial drainage. Unsaturated soils and soils
with higher permeability, in rapid shear, can dilate or collapse and generate negative or positive pore pressures which may, or may
not, dissipate in the shearing process. It is important to check the soil type being tested. It is very beneficial to sample the soil either
before or after testing, to understand the drainage conditions (permeability) of the soil tested.
5.5 This method also applies to hand held vane shear tests performed at shallow depths, however, hand held equipment may
be less accurate, because it may be more difficult to maintain vane/rod stability and verticality.
NOTE 2—The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the
equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing. Users
of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors;
Standard Practice D3740 provides a means of evaluating some of those factors.
6. Apparatus
6.1 Vane—A four-bladed vane as illustrated in Fig. 1. Vanes are normally constructed of steel. Different alloys of steel such as
nickel-chromium, or steel treatment processes such as hardening, can be used to reduce blade thickness. The ends of the vane may
be flat or tapered. Vane dimensions are as follows with notation from Fig. 1.
Vane Diameter, D: 35 to 100 mm [1.4 to 4 in.]
Vane Shaft Diameter, d: 12.5 to 16.5 mm [0.5 to 0.6 in.]
Vane Height, H: 1D # H # 2.5D
Taper Angle, i: usually 0 (rectangular) or 45 degrees (tapered)
6.1.1 The size of the vane selected should be the largest suitable for the anticipated conditions to be encountered. The diameter
selected is directly related to the consistency of the soil being tested. For softer soils, larger vane diameters, 75 to 100 mm [3 to
4 in.] are recommended and in stiffer soils, smaller vane diameters, 35 to 50 mm [1.5 to 2 in.] are required to avoid damage to
the torque measurement device (6.2). When used in drill holes, the maximum vane size is dependent on the inside diameter of the
boring or casing.
6.1.2 Blade Thickness—The vane blade shall have a thickness of 0.8 to 3 mm [0.031 to 0.118 in.]. The average thickness shall
be 2 mm [0.08 in.]. Vane blade edge or dimension (e) on Fig. 2 can be tapered to be thinner at the edges to reduce disturbance
from insertion.
6.1.3 The vane shaft diameter, d (shown also as 2r in Fig. 1) above the top of the vane blades shall be less than 20 mm [0.75
in.]. The vane shaft diameter (d) shall not exceed 14 mm [0.55 in.] at the center of the vane.
6.1.4 Vane Area Ratio (V )—As shown on the detail in Fig. 2, the vane blade edges and fillet rod and welds shall be sufficiently
A
small to minimize soil disturbance during insertion. The Vane Area Ratio must be less than 10 %.
6.1.5 The distance from the top edge of the vane to an increase in torque rod diameter (6.3) is 5d where d is the vane shaft
diameter at the top of the vane. If a large diameter friction coupler or torque rod sleeve is used, distance is 150 mm [6-in.].
6.1.6 A vane with the upper tapered edges has the advantage that the vane will not get caught on an exterior casing upon
withdrawal.
6.1.7 The bottom edge of the vane blades can be sharpened to facilitate penetration into the soil. The edges of the blades can
be sharpened and beveled to counter-rotate against a friction coupler (6.4).
6.2 Torque Measurement Device—Torque shall be applied to the rods, hence to the vane. This is accomplished with a clamping
device and torque application apparatus set at the top of the rods. The accuracy of the torque reading shall be such that it will
produce a variation not to exceed 61.0 kPa [621 lb/ft ] in computing undrained shear strength.
6.2.1 It is preferable to apply torque to the vane with a geared drive. In the absence of a geared drive, it is acceptable to apply
the torque directly by hand with a torque wrench or equivalent. If torque is applied by hand an asterisk shall be placed next to the
resultant shear stress and “hand torqued” shall be noted. The duration of the test shall be controlled by the requirements of 8.6.
6.2.2 Some torque measurement devices are capable of making hard copy or computer records of the load-displacement history.
Other manually read systems use torque rings and dial gauges. These automatic reading systems have an advantage over manually
read systems, because operator error is reduced.
6.3 Torque Rods—The vane shall be connected to the surface by means of steel torque rods. Typical rod diameters range from
18 to 36 mm [0.75 to 1.5 in.]. These rods shall have sufficient diameter such that their elastic limit is not exceeded when the vane
is stressed to its capacity (Note 3). They shall be so coupled that the shoulders of the male and female ends meet to prevent any
possibility of the coupling tightening when the torque is applied during the test. Most steel torque rods meeting the requirements
in this standard do twist during testing and requires a correction if vane rotation is to be determined.
NOTE 3—If torque versus rotation curves are to be determined, the torque rods can be calibrated. The amount of rod twist is established in degrees
per metre [foot] per unit torque. This correction becomes progressively more important as the depth of the test increases and the calibration must be made
D2573/D2573M − 18
at least to the maximum depth of testing anticipated. Alternately, rod twist can be calculated based on the properties of the rod. If twist is calculated, the
material property assumption must be reported.
6.3.1 Protective Casing and Vane Shoe—When using conventional drilling methods, torque rods can be sleeved in a small
diameter casing to reduce rod friction. If a torque rod sleeve or casing and vane shoe is used, the torque rods shall be equipped-with
well-lubricated bearings where they pass through the housing. These bearings shall be provided with seals that prevent soil from
entering them. The casing may require venting of water pressures. The test setup shall prevent friction from developing between
the torque rods and the walls of the casing or the boring (for example, by guiding the torque rods).
6.3.2 Rod friction measurements under no-load conditions can be performed by replacing the vanes with a blank stem only if
the torque is applied by a balanced moment that does not result in a side thrust. Some practitioners suggest the use of a vane that
allows some free rotation of the rod prior to loading. While this could be done to measure rod friction under no-load condition,
it is not a recommended practice. As torque becomes greater during a test, a side thrust in the instrument will result in an increase
in friction that is not accounted for by initial no-load readings. Instruments involving side thrust are not allowable.
6.4 Friction Coupling—The connection between the vane and the rods may include a friction coupling or slip coupling device.
This device is used with single rod systems where the vane may be advanced far in advance of the protective casing. This device
is designed not to engage the vane until a certain amount of rotation, typically 15 degrees has occurred, and thus allows for
determination of rod friction prior to the test. Use of this coupling is preferred over blank rod testing for determination of rod
friction, because measurements are made directly in the soil tested.
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