ASTM D8121 D8121M-2018 5000 Standard Test Method for Approximating the Shear Strength of Cohesive Soils by the Handheld Vane Shear Device.pdf

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1、Designation: D8121/D8121M 18Standard Test Method forApproximating the Shear Strength of Cohesive Soils by theHandheld Vane Shear Device1This standard is issued under the fixed designation D8121/D8121M; the number immediately following the designation indicates theyear of original adoption or, in the

2、 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. Scope1.1 This test method describes approximating the shearstrength of cohesive soils using a ha

3、ndheld (pocket) vane sheardevice.1.2 The device allows for a simple and portable method formeasuring the approximate undrained shear strength ofsaturated, fine-grained, cohesive soils. The test method can beused in the field or in the laboratory, on the ends of sampletubes, on the surface of block s

4、amples or excavations, or on thesurface of other test specimens with rigid confinement.1.3 UnitsThe values stated in either inch-pound units orSI units given in brackets are to be regarded separately asstandard. The values stated in each system may not be exactequivalents; therefore, each system sha

5、ll be used independentlyof the other. Combining values from the two systems mayresult in non-conformance with the standard. Tables of criticaldimensions and tolerances of the described vanes are providedin separate units of inches and mm.NOTE 1The original shear vane device was developed when shears

6、trength was often reported in tons per square foot (TSF) or kilograms persquare centimeter (kg/cm2) which are approximately equivalent. Theseunits have prevailed within the industry and are adopted herein.1.4 All observed and calculated values shall conform to theguidelines for significant digits an

7、d rounding established inPractice D6026, unless superseded by this test method.1.4.1 The procedures used to specify how data are collected,recorded, and calculated in this standard are regarded as theindustry standard. In addition, they are representative of thesignificant digits that generally shou

8、ld be retained. The proce-dures used do not consider material variation, purpose forobtaining the data, special purpose studies, or any consider-ations for the users objectives, and it is common practice toincrease or reduce significant digits of reported data to becommensurate with these considerat

9、ions. It is beyond the scopeof this test method to consider significant digits used inanalysis methods for engineering design.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish ap

10、pro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for the

11、Development of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil, Rock, and ContainedFluidsD2216 Test Methods for Laboratory Determination

12、 of Water(Moisture) Content of Soil and Rock by MassD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4648 Test Method for Laboratory Miniature Vane ShearTest for SaturatedFine-Grained Clayey SoilD6

13、026 Practice for Using Significant Digits in GeotechnicalData3. Terminology3.1 Definitions:3.1.1 For common definitions of technical terms used in thistest method, refer to Terminology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 vane multiplier (VM), na multiplier to correct thevan

14、es dial reading based on the standard (mid-size) vane to thelarger or smaller vane (4.2).3.2.2 calibration factor (CF), ncorrection to the vanesdial reading based upon the physical calibration of the torsionalshear device in accordance with Annex A1.1This test method is under the jurisdiction ofASTM

15、 Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.05 on Strength andCompressibility of Soils.Current edition approved June 1, 2018. Published July 2018. DOI: 10.1520/D8121_D8121M-182For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM

16、Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was d

17、eveloped in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.14. Summary of T

18、est Method4.1 The handheld vane shear device is comprised of acalibrated torque spring, post, measuring scale, and one ofthree vanes. A flat surface is prepared on a specimen ofcohesive soil, usually confined by a sampling tube or specimenring; the side walls of a test pit; or exposed footing. The v

19、aneis pressed into the soil surface and the device is rotated at aspecified rate until the soil shears. The failure surface isprescribed by the face of the vane and the depth of the blades.A pointer retains the maximum value on the measuring scale,ranging from 0 to 1 TSF 0 to 100 kPa, with major div

20、isionsof 0.05 TSF 5 kPa when a standard (mid-size) shear vane isused.4.2 Typically, three vane sizes are provided with the device.The standard (mid-sized) vane has a multiplier of 1. Thesmaller vane is used for stiffer soils and typically has amultiplier of 2.5. The larger vane is used for softer so

21、ils andtypically has a multiplier of 0.2. The reading on the scale ismultiplied by the factor for the specific vane to obtain thecorrect measure of strength.5. Significance and Use5.1 The handheld shear vane method provides a rapidmethod of measuring the approximate undrained shear strengthof a fine

22、-grained, cohesive soil either in the field or laboratory.This standard does not supplement or replace D4648.5.2 The device is intended for use in saturated cohesive soilsfor determining their approximate undrained shear strength.Cohesive soils with appreciable amounts of silt or fine sandmay experi

23、ence some degree of drainage during shear andadversely affect the results.NOTE 2The user will probably not know at the time of testing if thematerial is saturated. However, that would not preclude using the devicefor less than saturated conditions based on the knowledge and experienceof the user.5.3

24、 The presence of coarse materials or heterogeneous soilswithin the testing volume will adversely affect the results andmay preclude the use of this test method.5.4 The handheld shear vane test is not used to duplicate anyparticular field conditions but supplements the overall investi-gative program.

25、 However, consistent physical parameters areused in the test such that correlations of shear strength data canbe made to evaluate variability of a deposit, assess samplequality, assist in planning of laboratory testing programs, andto classify the consistency.NOTE 3The quality of the result produced

26、 by this standard isdependent on the competence of the personnel performing it, and thesuitability of the equipment and facilities used. Agencies that meet thecriteria of Practice D3740 are generally considered capable of competentand objective testing/sampling/inspection/etc. Users of this standard

27、 arecautioned that compliance with Practice D3740 does not in itself assurereliable results. Reliable results depend on many factors; Practice D3740provides a means of evaluating some of those factors.6. Apparatus6.1 Torsional Shear DeviceA mechanical device consist-ing of a calibrated torque spring

28、 attached to a measuring scaleand outfitted with one or multiple interchangeable vanes. Fig.1 shows an example of a typical torsional shear device withstandard (mid-size) vane attached, along with a smaller and aFIG. 1 Example of a Typical Torsional Shear Device with Standard (mid-size) Vane Attache

29、d, Along with Smaller and Larger Sized VanesD8121/D8121M 182larger sized vane. Fig. 23,4is an example schematic of thetorsional shear device.6.1.1 Torque SpringThe torque spring shall be calibratedfor the appropriate measuring scale. This is typically per-formed by the manufacturer at the time of as

30、sembly.6.1.2 Measuring ScaleThe measuring scale shall measurefrom 0 to 1 TSF 0 to 100 kPa, with major divisions of 0.05TSF 5 kPa, allowing interpolation to the nearest half division0.025 TSF 2.5kPa when the standard (mid-size) shear vane isattached. The measuring scale shall be outfitted with a poin

31、terthat retains the maximum value.NOTE 4The scale of some handheld shear vanes is provided inkilograms per square centimeter (kg/cm2) which are generally regarded asequivalent in value to tons per square foot (TSF) for this test method.6.1.3 KnobThe device shall have a knob that allows forgripping a

32、nd rotating of the device without impacting themeasured value on the scale.6.2 Vane(s)Vanes are constructed of stiff material such asmachined steel or aluminum, or plastic either injected moldedor 3D printed. At least one vane of known multiplier isrequired. Each vane shall have blades along the fac

33、e of thevane. Each blade shall extend from the face of the vane. Thedepth of the blade affects the multiplier for the vane. Themultiplier for the vane is provided by the manufacturer andgenerally 1 by the standard 1 in. 25.4 mm vane; 2.5 for thehigh capacity34-in. 19.0 mm vane and 0.2 for the sensit

34、ive1-78-in. 47.6 mm vane. Fig. 3 illustrates the configuration ofthe vanes.6.2.1 Table 1 provides the critical dimensions and tolerancesin inches for the three vane sizes. Table 2 provides similarinformation as Table 1, but in mm. Table 3 provides thicknessin in. and mm for vanes of machined stainle

35、ss steel oraluminum, and injected plastic. See Appendix X1 for theequations used to determine the multiplier for a vane, given itsdimensions.6.2.2 Calibration MassesCalibration masses causing ap-proximately 30 percent, 60 percent, and 90 percent of thefull-scale reading. See Annex A1 for calibration

36、 procedures.6.3 Straight EdgeSteel straight edge at least 6 in. 150mm in length with one beveled edge or a flat edged paintscraper.6.4 Measuring DeviceThe device to measure the vanedimensions shall be capable of measuring to the nearest 0.001in. 0.01 mm or better.6.5 If the user elects to determine

37、water contents of the testsample, that apparatus required to perform D2216 will berequired.7. Specimen Preparation7.1 Using a straight edge, create a flat surface on the end ofa confinement ring or test area. The surface should be preparedwith minimal disturbance. If disturbance does occur the users

38、hould prepare an alternate surface if feasible or document theobserved disturbance in the data record.8. Preparation of Apparatus8.1 Select the vane size appropriate for the estimated shearstrength. Several trials may be required to determine whichvane will cause an acceptable measurement as describ

39、ed in 9.8.9. Procedure9.1 Record the vane size, vane multiplier, and calibrationfactor.9.2 Move the scale pointer to read zero.9.3 Press the handheld shear vane into the soil surface suchthat the axis of the post is normal to the soil surface.3E. A. Sibley and G. Yamane, “A Simple Shear Test for Sat

40、urated CohesiveSoils”, Vane Shear and Cone Penetration Resistance Testing of In-Situ Soils, STP399, ASTM International, 1966, pp 39-47.4The boldface numbers in parentheses refer to a list of references at the end ofthis standard.FIG. 2 Example Schematic of the Torsional Shear Device3,4D8121/D8121M 1

41、839.4 Penetrate the blades of the vane until the face of thevane is flush with the soil surface.9.5 Place the thumb of one hand against the back of thevane. Apply only sufficient force to the axis of the handheldshear vane to maintain contact between the face of the vane andthe soil surface without

42、penetrating the face of the vane into thesoil surface. Excess thumb pressure will hinder the vanerotation during shear.9.6 Place the tips of the fingers of the free hand on the edgeof the knob. Take care that the fingers do not hang over theedge of the dial and touch the scale or the pointer. Rotate

43、 thevane clockwise using one smooth motion at a rate that causesfailure in 5 to 10 seconds.9.7 Record the value indicated by the pointer to the nearesthalf division, 0.025 TSF 2.5 kPa.9.8 If the value indicated by the pointer is less than 10percent of the scale and the largest vane is not being used

44、, usethe next largest vane to check the results. Likewise, if the valueis more than 90 percent of the scale and the smallest vane is notbeing used, use the next smallest vane to check the results. Ifpossible, repeat the measurement in an untested location on thesoil surface. Take care to space the m

45、easurements far enoughapart that the failure disk of one measurement does not causepremature failure of the adjacent test.9.9 For optional water content determination, remove thesoil from between the blades. Place the soil in a pre-measuredtare for water content determination in accordance with D221

46、6.9.10 If required to meet the minimum mass requirements forthe water content determination, remove additional soil to thedepth of the device blades in the tested areas. Place the soil inthe water content tare, and obtain the water content.FIG. 3 Vane Configuration (a) High Capacity, (b) Standard, (

47、c) SensitiveTABLE 1 Vane Critical Inch Dimensions and TolerancesVane Head BladeLengthNo. Blades Blade Length Blade Height Blade ODLength, in. Tol., in. Height, in. Tol., in. Nominal, in. OD, in. Tol., in.Standard NA 8 0.312 0.003 0.200 0.004 1 1.000 0.002HighCapacityNA 8 0.215 0.003 0.137 0.00434 0.

48、750 0.002Sensitive Long 8 0.690 0.003 0.200 0.004 1-78 1.875 0.004Short 8 0.285 0.003 0.200 0.004 1-78 1.875 0.004TABLE 2 Vane Critical SI Dimensions and TolerancesVane Head Blade Length No. Blades Blade Length Blade Height Blade ODLength, mm Tol., mm Height, mm Tol., mm OD, mm Tol., mmStandard NA 8

49、 7.70 0.005 5.2 0.1 25.4 +0/0.05High Capacity NA 8 5.55 0.005 5.2 0.1 19.1 0.05Sensitive Long 8 17.50 0.005 5.2 0.1 48.0 0.1Short 8 7.25 0.005 5.2 0.1 48.0 0.1TABLE 3 Blade Width for Machined Stainless Steel and InjectedPlasticBlade Width, in. Blade Width, mmWidth, in. Tol., in. Width, mm Tol., mmMachinedSS0.030 0.002 0.75 0.05InjectedPlastic0.035 0.004 0.90 0.1D8121/D8121M 18410. Calculations10.1 Correct each reading by the calibration factor, ifrequired, and the vane multiplier for the vane used for thede