ASTM D2573-2008 Standard Test Method for Field Vane Shear Test in Cohesive Soil《粘性土十字板剪切试验的标准试验方法》.pdf

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1、Designation: D 2573 08Standard Test Method forField Vane Shear Test in Cohesive Soil1This standard is issued under the fixed designation D 2573; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in

2、 parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers the field vane test in saturatedclay a

3、nd silt soils for determination of undrained shearstrength. Knowledge of the nature of the soil in which eachvane test is to be made is necessary for assessment of theapplicability and interpretation of the test. The test is notapplicable for sandy soils which may allow drainage during thetest.1.2 T

4、his test method addresses testing on land and fortesting in drill holes or by self drilling or continuous pushmethods from the ground surface. This method does notaddress specifically marine testing where special test require-ments or variations in equipment may be required. The user isreferred to A

5、STM STP 1014 for additional information onin-place vane shear testing.21.3 This method is often used in conjunction with fluidrotary drilling (D 5783) or hollow-stem augers (D 6151). Someapparatuses have the vane retracted in protective shoe foradvancement and incremental testing. Sampling, such as

6、withthin wall tubes (D 1587) is often combined with vane testing.Subsurface geotechnical explorations are reported in accor-dance with practice (D 5434).1.4 Undrained shear strength and sensitivity of cohesivesoils can also be measured in Unconfined Compression D 2166and Laboratory Vane Test (D 4648

7、).1.5 The values stated in SI units are to be regarded as thestandard. English (Imperial) units are given in parentheses.1.6 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 appro-p

8、riate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D 653 Terminology Relating to Soil, Rock, and ContainedFluidsD 1587 Practice for Thin-Walled Tube Sampling of Soilsfor Geotechnical PurposesD 2166 Test

9、 Method for Unconfined Compressive Strengthof Cohesive SoilD 2488 Practice for Description and Identification of Soils(Visual-Manual Procedure)D 3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD 464

10、8 Test Method for Laboratory Miniature Vane ShearTest for SaturatedFine-Grained Clayey SoilD 5434 Guide for Field Logging of Subsurface Explora-tions of Soil and RockD 5783 Guide for Use of Direct Rotary Drilling withWater-Based Drilling Fluid for Geoenvironmental Explo-ration and the Installation o

11、f Subsurface Water-QualityMonitoring DevicesD 6151 Practice for Using Hollow-Stem Augers for Geo-technical Exploration and Soil Sampling2.2 Other Standards:Recommended Standard for Field Vane Shear Test, Swed-ish Geotechnical Society, SGF Report 2:93E, SwedishGeotechnical Institute, Linkping: www.sw

12、edgeo.seEuroCode 7: Geotechnical DesignPart 3 Design Assistedby Field Testing, ENV 1997-3:1999E, CEN3. Terminology3.1 Definitions:3.1.1 For common definitions of terms in this standard, referto Terminology D 653.1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is

13、the direct responsibility of Subcommittee D18.02 on Sampling andRelated Field Testing for Soil Evaluations.Current edition approved Oct. 1, 2008. Published October 2008. Originallyapproved in 1967. Last previous edition approved in 2007 as D 2573 01 (2007).2ASTM STP 1014 on Vane Shear Strength Testi

14、ng in Soils (1988).3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at

15、the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.2 sensitivitythe effect of remolding on the consistencyof cohesive soil.3.1.3 vane shear test (VST)an in-place shear test in whicha rod with thin radial vane

16、s at the end is forced into the soil andthe resistance to rotation of the rod is determined.3.2 Definitions of Terms Specific to This Standard:3.2.1 remolded undrained shear strengthshear strength offine-grained soil in rapid loading with little or no drainage ofpore water pressure after significant

17、 failure and remolding ofthe initial soil structure. (Also see D 2166 and D 4648).3.2.2 undrained shear strengthshear strength of fine-grained soil (primarily clays and clayey silts) in rapid loadingwith essentially no drainage of porewater pressure. (Also seeD 2166 and D 4648).3.2.3 vanea device wi

18、th four, thin, flat metal blades orplates, fixed at an angle of 90 degrees to each other, which isinserted into the soil and then rotated about a vertical axis forshear testing (see Fig. 1).3.2.4 vane shoea section of drill casing and cutting bit atthe end in which the vane can be retracted while dr

19、illing orpushing3.3 Symbols:3.3.1 In accordance with ASTM D 653.3.3.2 shear strength, suthe maximum (undrained) resis-tance of soil to shearing stresses.3.4 Symbols Specific to This Standard:3.4.1 peak undrained shear strength, (su)fvthe peak und-rained shearing resistance measured during the initia

20、l rotationof the vane in a vane shear test.3.4.2 remolded undrained shear strength, (sur)fvthe re-molded undrained shear strength is measured after five to tenvane rotations in a vane shear test.3.4.3 sensitivitySTfvthe ratio of peak undrained shearstrength to remolded undrained shear strength measu

21、red in thefield vane shear test: STfv=(su)fv/(sur)fv. The remolded shearstrength is measured after large shearing strains (see 8.7 and9.3).NOTE 1Previous and existing standards have specified differentamounts of rotation, from 5 to 25 revolutions, for measurement ofremolded strength.2If sensitivity

22、is reported, the number of revolutionsmust also be reported. Sensitivity can also be measured in unconfinedcompression testing (D 2166) and laboratory vane testing (D 4648).3.4.4 torqueT, (FL)the measured torque (or moment)required to rotate the vane.3.4.5 vane area ratioVA% the ratio of the cross s

23、ectionarea of the vane to the circular area of the rotated vaneexpressed as a percent (see Fig. 2).3.5 Acronyms:3.5.1 VSTvane shear test.3.5.2 FVfield vane.4. Summary of Test Method4.1 The vane shear test consists of placing a four-bladedvane in the intact soil and rotating it from the surface todet

24、ermine the torque required to shear a cylindrical surfacewith the vane. This torque, or moment, is then converted to athe unit shearing resistance of the failure surface by limitequilibrium analysis. Friction of the vane rod and instrumentare either minimized during readings by special casings orhou

25、sing, or else accounted for and subtracted from the totaltorque to determine the torque applied to the vane.5. Significance and Use5.1 This test method provides an indication of in-situundrained shear strength of fine- grained clays and silts or otherfine geomaterials such as mine tailings, organic

26、muck, andsubstances where undrained strength determination is required.The test is applicable to soils with undrained strengths of lessthan 200 kPa (2 tsf). Very sensitive soils can be remoldedduring vane insertion.5.2 This test method is used extensively in a variety ofgeotechnical explorations to

27、evaluate rapid loading strength fortotal stress analysis of saturated fine-grained clays and silts.The test is routinely performed in conjunction with other fieldand laboratory tests.5.3 The peak undrained shear resistance of the vane test iscommonly corrected to determine the undrained shear streng

28、thfor geotechnical analysis. The agency requesting the testingmust interpret these data to determine applicability for strengthanalysis. It is beyond the scope of this standard to recommendapplicability of vane testing for geotechnical analysis. Forinformation on the general use of these correction

29、factors,consult Appendix X1.5.4 This method is not applicable in sands, gravels, or otherhigh permeability soils. With the shearing rates described inthis standard, sand lenses, if present, will allow total or partialdrainage. Soils with higher permeability, in rapid shear, candilate or collapse and

30、 generate negative or positive porepressures which may, or may not, dissipate in the shearingprocess. It is important to check the soil type being tested. It isvery beneficial to sample the soil either before or after testing,to understand the drainage conditions (permeability) of the soiltested.5.5

31、 This test is often performed in drilled boreholes or withself-push or self-drilling or pushed (vane shoe) methods. Thismethod also applies to hand held vane shear tests performed atshallow depths, however, hand held equipment may be lessaccurate, because it may be more difficult to maintain vane/ro

32、dstability and verticality.NOTE 2The quality of the result produced by this standard isFIG. 1 Geometry of Field VanesD2573082dependent on the competence of the personnel performing it, and thesuitability of the equipment and facilities used. Agencies that meet thecriteria of Practice D 3740 are gene

33、rally considered capable of competentand objective testing. Users of this standard are cautioned that compliancewith Practice D 3740 does not in itself assure reliable results. Reliableresults depend on many factors; Standard Practice D 3740 provides ameans of evaluating some of those factors.6. App

34、aratus6.1 The vane shall consist of a four-bladed vane as illus-trated in Fig. 1. Vanes are normally constructed of steel.Different alloys of steel such as nickel-chromium, or steeltreatment processes such as hardening, can be used to reduceblade thickness. The ends of the vane may be flat or tapere

35、d.Vane dimensions are as follows with notation from Fig. 1.Vane Diameter, D: 35 to 100 mm (1.5 to 4 in.)Vane Shaft Diameter, d: 12.5 to 16.5 mm (0.5 in.)Vane Height, H: 1D # H # 2.5DTaper Angle, i: usually 0 (rectangular) or 45 degrees (tapered)6.1.1 For good torque resolution, select a vane diamete

36、r thatis large enough to provide optimum torque resolution. Thediameter selected is directly related to the consistency of thesoil being tested. For softer soils, larger sizes are required forgood resolution. In stiffer soils, smaller vanes are required toavoid damage to the torque measurement devic

37、e (6.2). Whenused in drill holes, the maximum vane size is dependent on theinside diameter of the boring or casing.6.1.2 Blade ThicknessMaximum blade thickness is lim-ited toe 5 % recommends the following expression (3):v5 1.05 b PI!0.5(X1.2)where the parameter b is a rate factor that depends upon t

38、hetime-to-failure (tfin minutes) in the actual failure (not in thefield test) and given by:b 5 0.015 1 0.0075 log tf(X1.3)The combined relationships are shown in Fig. X1.1. Forguidance, embankments on soft ground are normally associ-ated with tfon the order of 104minutes because of the timeinvolved

39、in construction using large equipment. For this case,Eq X1.2 becomes:v5 1.05 0.045 PI!0.5(X1.4)X1.2.2 Interestingly, the raw vane strength ratio (suv/svo8)has long been observed to increase with plasticity index (forexample, (4). Conversely, the vane correction factor (v)decreases with PI. The net e

40、ffect is that the mobilized strengthback calculated from failure case histories involving embank-ments, foundations, and excavations in soft clays is essentiallyindependent of plasticity index (for example, (5). Aas, et.al.(6) have proposed a correction method which uses (suv/svo8)asthe independent

41、variable rather than PI.X1.2.3 Alternative correction factors are given based oncompilations of back calculated failures of foundations, em-bankments, and excavations (2), field load tests and laboratorydata (7), three-dimensional stability considerations (8), labora-tory shear data (5), and oedomet

42、er data (9), as well as effectivestress analyses (10, 11).D2573087REFERENCES(1) Bjerrum, L. (1972). Embankments on soft ground. Performance ofEarth and Earth-Supported Structures, Vol. II, (Purdue Conference),ASCE, Reston, VA, 1-54.(2) Bjerrum, L. (1973). Problems of soil mechanics or through the ASTM website(www.astm.org).FIG. X1.1 Proposed Correction Factor to Raw Field Vane ShearData from Plasticity Index (after Chandler, 1988)D2573088