1、Designation: D4648/D4648M 13D4648/D4648M 16Standard Test MethodMethods forLaboratory Miniature Vane Shear Test for SaturatedFine-Grained Clayey Soil1This standard is issued under the fixed designation D4648/D4648M; the number immediately following the designation indicates theyear of original adopti
2、on or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 ThisThese test method coversmethods cover the miniature vane test in very
3、 soft to stiff saturated fine-grained clayey soils( = 0). Knowledge of the nature of the soil in which each vane test is to be made is necessary for assessment of the applicabilityand interpretation of the test results.NOTE 1It is recommended that the miniature vane test be conducted in fine-grained
4、, predominately clay soils with an undrained shear strength lessthan 1.0 tsf 100 kPa. Vane failure conditions in higher strength clay and predominantly silty soils may deviate from the assumed cylindrical failuresurface, thereby causing error in the measured strength.1.2 ThisThese test method includ
5、esmethods include the use of both conventional calibrated torque spring units (MethodA) andelectrical torque transducer units (Method B) with a motorized miniature vane shear device.1.3 Laboratory vane is an ideal tool to investigate strength anisotropy in the vertical and horizontal directions, if
6、suitablesamples (specimens) are available.1.4 All measured and calculated values shall conform to the guidelines for significant digits and rounding established in PracticeD6026.1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated
7、in eachsystem may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result in non-conformance with the standard.1.5.1 The gravitational system of inch-pound units is used when dealing with inch-pound units. In this sys
8、tem, 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 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the re
9、sponsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil, Rock, and Contained FluidsD1587 Practice for Thin-Walled T
10、ube Sampling of Fine-Grained Soils for Geotechnical PurposesD2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by MassD2488 Practice for Description and Identification of Soils (Visual-Manual Procedure)D2573 Test Method for Field Vane Shear Test in Saturated
11、 Fine-Grained SoilsD3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used inEngineering Design and ConstructionD4220 Practices for Preserving and Transporting Soil SamplesD6026 Practice for Using Significant Digits in Geotechnical Data1 Thi
12、s test method is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.05 on Strength andCompressibility of Soils.Current edition approved Feb. 1, 2013Jan. 1, 2016. Published March 2013January 2016. Originally approved in 1987. Last previo
13、us edition approved in 20102013 asD4648/D4648M 10.13. DOI: 10.1520/D4648_D4648M-13.10.1520/D4648_D4648M-16.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standa
14、rds Document Summary page on the ASTM website.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. Becauseit may not be technically possible to adequately depict all changes accurately
15、, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive
16、, PO Box C700, West Conshohocken, PA 19428-2959. United States13. Terminology3.1 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 torquethe product of the magnitude of a force and the perpendicular
17、distance of the line of action of the force from aspecified axis of rotation.3.2.2 torque springan elastic spring that can be calibrated to provide a measure of torque that is proportional to the rotation(about a central longitudinal axis) of one end of the spring relative to a fixed condition at th
18、e opposite end of the spring.3.2.3 torque transduceran electronic measuring device that can be calibrated to provide a measure of torque.4. Summary of Test Method4.1 The miniature vane shear test consists of inserting a four-bladed vane in the end of an undisturbedintact tube sample orremolded sampl
19、e and rotating it at a constant rate to determine the torque required to cause a cylindrical surface to be sheared bythe vane. This torque is then converted to a unit shearing resistance of the cylindrical surface area. The torque is measured by acalibrated torque spring or torque transducer that is
20、 attached directly to the vane.5. Significance and Use5.1 The miniature vane shear test may be used to obtain estimates of the undrained shear strength of fine-grained soils. The testprovides a rapid determination of the shear strength on undisturbed, or remolded or reconstituted soils.NOTE 2Notwith
21、standing the statements on precision and bias contained in this test method: The precision of this test method is dependent on thecompetence of the personnel performing it and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 aregenerally conside
22、red capable of competent and objective testing. Users of this test method are cautioned that compliance with Practice D3740 does notin itself ensure reliable testing. Reliable testing depends on several factors; Practice D3740 provides a means for evaluating some of those factors.6. Interferences6.1
23、 Vane DisturbanceThe remolded zone around a vane blade resulting from insertion is generally assumed to be small andhave little or no effect on the stress-strain properties of the sediment being tested. In reality, the volume of soil disturbed by theinsertion of the vane blade into the assumed cylin
24、drical volume of soil being tested may be significant. It is recommended that thevane displace no more than 15% of the soil being tested as defined by the vane area ratio presented in Fig. 1.7. Apparatus7.1 Vane BladeThe vane assembly shall consist of four rectangular bladed vanes, as illustrated in
25、 Fig. 2. It is recommendedthat the height of the vane be twice the diameter (2:1), although vanes with a height equal to the diameter (1:1) also may be used(see Note 3). Vane blade diameter (D) may vary from 0.5 to 1.0 in. 12.7 to 25.4 mm.FIG. 1 Vane Area Ratio for ASTM VanesD4648/D4648M 1627.2 Vane
26、 DeviceThe vane device should be motorized and, in the case of a torque spring device, shall rotate the torque springat a constant rate of 60 to 90/min 1.0 to 1.6 rd/min.rad/min.Avane device which applies the torque directly through a stiff shaftusing an electrical transducer to measure torque shall
27、 rotate the vane at a constant rate that ranges from 20 to 30/min 0.35 to 0.52rd/min.rad/min. The vane/spring rotation device shall have an indicator or recording system that displays/records deflection(torque) of the calibrated spring or electrical transducer and, where possible, vane blade rotatio
28、n.7.3 Torque Measuring DeviceThe torque measuring device shall be a conventional torque spring, electrical torque transducer,or any other measuring device capable of the accuracy prescribed herein and may be part of the vane device. The torque measuringdevice shall be capable of measuring the torque
29、 to at least three significant digits.NOTE 3Since many clays are anisotropic with respect to strength, the relative importance of horizontal, as distinct from vertical, shearing surfacescan influence the test results. For this reason it is important that the recommended ratio of height to diameter b
30、e respected unless the intent is to varythe ratio in order to determine the horizontal and vertical strengths separately. For more detailed discussion on effects of height to diameter ratio as wellas vane shape, refer to Refs. (1) and (2).38. Preparation and Testing of Samples8.1 Specimen SizeSpecim
31、ens should have a diameter sufficient to allow clearance of at least two blade diameters between allpoints on the circumference of the shearing surface and the outer edge of the sample.8.2 UndisturbedIntact Vane StrengthPrepare undisturbedintact specimens from large undisturbedintact samples secured
32、 inaccordance with Practice D1587, and handle and transport in accordance with the practices for Group C and D Samples in PracticesD4220. Tests may be run in the sampling tube, eliminating the need for extrusion. Handle specimens carefully to preventdisturbance or loss of moisture water (moisture) c
33、ontent. Trim flat the end of the sample where the vane will be inserted. Thesample shall be perpendicular to the wall of the tube.8.3 Remolded Vane StrengthConduct remolded miniature vane strength tests on failed specimens similar to remolded fieldvane tests (Test Method D2573) by rotating the vane
34、rapidly through a minimum of five to ten revolutions.NOTE 4Remolded shear strength measurements are conventionally obtained by conducting strength tests on specimens encased in a thin rubbermembrane, to prevent change in water content, and remolded by hand (hand remolding). Field vane remolded stren
35、gth has however been obtained byrotating the vane rapidly through a minimum of five to ten complete revolutions and conducting a vane test within 1 min of the remolding process(machine remolding). A machine remolded test yields a vane strength value that is considered more a residual strength. The m
36、achine remolded strengthis typically higher than the hand remolded strength and, as a consequence, produces lower sensitivities. In many sensitive clayey soils, residual strengthsmay be obtained within one to two revolutions or less. If such soils are being tested, it is recommended that several rem
37、olded strengths be obtained usingthe standard five to ten revolutions for verification. If no major remolded strength differences are noted, remolded strengths may be obtained at less thanthe recommended five to ten revolutions.NOTE 5In cases where electrical torque transducers with wires for signal
38、 transmission are utilized, the remolded miniature vane strength may beobtained by rotating the vane one complete revolution in one direction and then again in the opposite direction a number of times to produce the desiredfive to ten complete revolutions.3 The boldface numbers in parentheses refer
39、to the list of references at the end of this standard.FIG. 2 Miniature Vane Blade GeometryD4648/D4648M 1639. Preparation of Apparatus9.1 Vane Blade DamageCarefully check each vane prior to each use for bent shafts and blades and imperfections that couldalter the vane failure surface from the assumed
40、 cylindrical surface.10. Calibration10.1 Conduct periodically calibration of the spring units (or torque transducers) to ensure proper operation of the miniature vanedevice and repeatability of the torque spring or transducers. Calibration is accomplished by the application of calibrated weightsonto
41、 a calibrated wheel to produce a known torque (lever arm X weight). Secure the vane shear unit in such a way that the vanespring (torque unit) is in a horizontal position. Then insert the calibration wheel in place of the vane blade. The calibration wheel,calibration string, and calibration weights
42、all shall hang free of any obstructions. Dimensions of the calibration wheel shall benoted; specifically the lever arm.10.2 For each vane torque spring to be used, apply a series of calibration weights to the calibration wheel to develop a plot ofspring deflection (in degrees) versus torque (in lbfi
43、n. or Nm). Carefully fasten each calibration weight to the calibration stringand allow to deflect the spring. Record the deflection of the spring (in degrees) and applied torque for each weight applied. Thecalibration wheel configuration, lever arm, weights, and resulting torque shown in Fig. 3 is r
44、ecommended for consideration in thecalibration procedure.11. Application and Measurement of Vane Blade Torque11.1 Apply the torque to the vane by a conventional torque spring (Fig. 4a) or an electrical torque transducer (Fig. 4b) that isrotated with the vane/spring rotation device. The torque spring
45、 or transducer shall produce a repeatable linear relationship betweenspring deflection (degrees) or transducer output (mV) and torque applied.NOTE 6Since vane strength may be greatly influenced by the rate at which shear occurs, it is recommended that torque be applied using a motorizedvane device.
46、A hand crank manual device may be utilized, but is not recommended due to the potential variation in rate of shear.NOTE 7When the miniature vane test is conducted using a calibrated torque spring, the top of the spring unit is rotated at a constant rotation ratewhile the bottom of the spring most of
47、ten remains stationary or nearly stationary until enough energy (torque) is built up in the spring. Just prior to orat failure, the bottom of the spring and vane begin to rotate (generally slowly) as failure begins. The torque applied by the spring soon overcomes theshearing resistance of the soil a
48、nd the vane blade rotates rapidly to bring the soil to total failure. Thus, depending upon the stiffness of the calibrated torquespring, soil strength, and consistency, the rate of shear and possibly the shear strength may vary.NOTE 8It should be recognized that there is a fundamental difference in
49、the failure modes between miniature vane tests made using a calibrated torquespring and an electrical transducer. An electrical torque transducer will produce a strain-controlled failure of the soil, whereas a calibrated torque springwill produce failure that varies somewhere between purely stress-controlled and strain-controlled conditions. Using an electrical torque transducer, theconstant rate of rotation applied to the top of the torque transducer is transmitted directly to the vane blade. The resulting strain-controlled failure couldresul
