1、Designation: D6467 13Standard Test Method forTorsional Ring Shear Test to Determine Drained ResidualShear Strength of Cohesive Soils1This standard is issued under the fixed designation D6467; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method provides a procedure for performing atorsional ring shear test under a drained
3、condition to determinethe residual shear strength of cohesive soils. An intact speci-men can be used for testing. However, obtaining a natural slipsurface specimen, determining the direction of field shearing,and trimming and aligning the usually non-horizontal shearsurface in the ring shear apparat
4、us is difficult. As a result, thistest method focuses on the use of a reconstituted specimen tomeasure the residual strength. This test method is performed bydeforming a presheared, reconstituted specimen at a controlleddisplacement rate until the constant drained shear resistance isoffered on a sin
5、gle shear plane determined by the configurationof the apparatus. An unlimited amount of continuous sheardisplacement can be achieved to obtain a residual strengthcondition. Generally, three or more normal stresses are appliedto a test specimen to determine the drained residual failureenvelope. A sep
6、arate test specimen may be used for eachnormal stress.1.2 A shear stress-displacement relationship may be ob-tained from this test method. However, a shear stress-strainrelationship or any associated quantity, such as modulus,cannot be determined from this test method because soilextrusion and volum
7、e change prevents defining the heightneeded in the shear strain calculations. As a result, shear straincannot be calculated but shear displacement can be calculated.1.3 The selection of normal stresses and determination ofthe shear strength envelope for design analyses and the criteriato interpret a
8、nd evaluate the test results are the responsibility ofthe engineer or office requesting the test.1.4 The values stated in SI units are to be regarded asstandard. The values given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and are not consid
9、ered standard.1.5 All measured and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.6 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 s
10、tandard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D422 Test Method for Particle-Size Analysis of SoilsD653 Terminology Relating to Soil, Rock, and ContainedFluidsD854 Test M
11、ethods for Specific Gravity of Soil Solids byWater PycnometerD2216 Test Methods for Laboratory Determination of Water(Moisture) Content of Soil and Rock by MassD2435 Test Methods for One-Dimensional ConsolidationProperties of Soils Using Incremental LoadingD2487 Practice for Classification of Soils
12、for EngineeringPurposes (Unified Soil Classification System)D3080 Test Method for Direct Shear Test of Soils UnderConsolidated Drained ConditionsD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD431
13、8 Test Methods for Liquid Limit, Plastic Limit, andPlasticity Index of SoilsD6026 Practice for Using Significant Digits in GeotechnicalData3. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, refer to Terminology D653.3.2 Definitions of Terms Specific to This Standard:1This
14、 test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.05 on Strength andCompressibility of Soils.Current edition approved May 1, 2013. Published July 2013. Originally approvedin 1999. Last previous edition approved in 2006 as
15、 D6467 06a. DOI: 10.1520/D6467-13.2For 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.*A Summary of Changes secti
16、on appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.1 consolidatedsoil specimen condition after primaryconsolidation under a specific normal stress.3.2.2 preshearedsoil specimen condition after sh
17、earing toat least one revolution of the ring in the direction of shear tocreate a failure surface prior to drained shearing.3.2.3 residual shear forcethe shear force is the averageforce being applied to the specimen when the shear resistanceneither increases nor decreases with continued shear displa
18、ce-ment.3.2.4 residual shear strengththe minimum constant resis-tance of soil to shear along a fully developed failure surfaceand equals the residual shear force divided by the cross-sectional area of the specimen.3.2.5 drained residual strength statethe state at which asoil exhibits residual shear
19、strength and shear stress sheardisplacement relationship becomes almost horizontal.4. Summary of Test Method4.1 This test method consists of placing the specimen in theannular specimen container, applying a predetermined normalstress through the top loading platen, providing for wetting anddraining
20、of the specimen (optional); consolidating the speci-men under the normal stress; decreasing the normal stress toyield an overconsolidated specimen; preshearing the specimenby rotating the specimen container against the top loadingplaten for one revolution; applying a constant rate of sheardeformatio
21、n rotation; and measuring the torque/shearing forceand rotation displacement until a constant value of shearingresistance is reached.5. Significance and Use5.1 The ring shear test is suited to the relatively rapiddetermination of drained residual shear strength because of theshort drainage path thro
22、ugh the thin specimen, and the capa-bility of testing one specimen under different normal stresses toquickly obtain a shear strength envelope.5.2 The test results are primarily applicable to assess theshear strength in slopes that contain a preexisting shear surface,such as old landslides, solifluct
23、ed slopes, and sheared beddingplanes, joints, or faults.5.3 The apparatus allows a reconstituted specimen to beoverconsolidated and presheared prior to drained shearing.This simulates the field conditions that lead to a preexistingshear surface along which the drained residual strength can bemobiliz
24、ed.5.4 The ring shear device keeps the cross-sectional area ofthe shear surface constant during shear and shears the specimencontinuously in one rotational direction for any magnitude ofdisplacement. This allows clay particles to become orientedparallel to the direction of shear and a residual stren
25、gthcondition to develop.NOTE 1Notwithstanding the statements on precision and bias con-tained in this test method: The precision of this test method is dependenton the competence of the personnel performing it and the suitability of theequipment and facilities used. Agencies that meet the criteria o
26、f PracticeD3740 are generally considered capable of competent testing. Users ofthis test method are cautioned that compliance with Practice D3740 doesnot ensure reliable testing. Reliable testing depends on several factors;Practice D3740 provides a means of evaluating some of those factors.6. Appara
27、tus6.1 Shear Device, to hold the specimen securely betweentwo porous discs. The shear device provides a mean forapplying a normal stress to the faces of the specimen, formeasuring changes in thickness of the specimen, for permittingdrainage of water through the porous discs at the top andbottom boun
28、daries of the specimen, and for submerging thespecimen in water. The device is capable of applying a torqueto the specimen along a shear plane parallel to the faces of thespecimen. A number of different ring shear devices are com-mercially available, in practice, or are being developed so ageneral d
29、escription of a ring shear device is presented withoutschematic diagrams. The location of the shear plane dependson the configuration of the apparatus. As a result, the shearplane may be located near a soil/porous disc interface or at themid-height of the specimen if an upper ring can be separatedfr
30、om a bottom ring as is done in a direct shear box. The deviceshall have low friction along the inner and outer walls of thespecimen container developed during shearing. Friction maybe reduced by having the shear plane occur at the top of thespecimen container, modifying the specimen container wallsw
31、ith low-friction material. The frames that hold the specimenshall be sufficiently rigid to prevent their distortion duringshearing. The various parts of the shear device shall be made ofa material such as stainless steel, bronze, or coated aluminumthat is not subject to corrosion by moisture or subs
32、tances withinthe soil. Dissimilar metals, which may cause galvanic action,are not permitted.6.2 Specimen Container, a device containing an annularcavity for the soil specimen with an inside diameter not lessthan 50 mm (2 in.) and an inside to outside diameter ratio notless than 0.6.The container has
33、 provisions for drainage throughthe top and bottom. The initial specimen depth, before con-solidation and preshearing, is not less than 5 mm (0.2 in.). Themaximum particle size is limited to 10 % of the initialspecimen height as stated in the test specimen description.6.3 Torque Arm/Loading Platen A
34、ssembly, may have differ-ent bearing stops for the proving rings, load cells, or force ortorque transducers to provide different options for the torquemeasurement.6.4 Porous Discs, two bronze or stainless steel porous discsmounted on the top loading platen and the bottom of thespecimen container cav
35、ity to allow drainage from the soilspecimen along the top and bottom boundaries. The inserts aidin transfer of shear stress to the top and bottom boundaries ofthe specimen. The inserts must be sufficiently serrated todevelop a strong interlock with the soil specimen. The perme-ability of the inserts
36、 shall be substantially greater than that ofthe soil, but shall be textured fine enough to prevent excessiveintrusion of the soil into the pores of the insert. The outer andinner diameters of the inserts shall be 0.1 mm (0.004 in.) less,and greater than those of the specimen annular cavity, respec-t
37、ively. The serration should have a depth of between 10 and15 % of the initial specimen height. The porous discs shall beclean and free from cracks, chips, and nonuniformities. NewD6467 132porous discs should be boiled for at least 10 minutes and left inthe water to cool to ambient temperature before
38、 use. Immedi-ately after each use, clean the porous discs with a nonabrasivebrush and boil to remove clay particles that may reduce theirpermeability.NOTE 2Exact criteria for porous disc texture and permeability havenot been established. The grade of the porous disc shall be fine enough toprevent in
39、trusion of soil into the pores. For normal soil testing, medium-grade inserts with a permeability of about 5.0 104to 1.0 103cm/s(0.5 to 1.0 103ft/year) are appropriate for testing silts and clays. It isimportant that the permeability of the porous disc is not reduced by thecollection of soil particl
40、es in the pores of the insert; hence frequentchecking and cleaning (by flushing and boiling, or by ultrasonic cleaning)is required to ensure that the permeability is not reduced.6.5 Loading Devices:6.5.1 Device for Applying and Measuring the NormalForceNormal force is usually applied by a lever-load
41、ingyoke that is activated by dead weights (masses) or by anyautomatic loading mechanism. The device shall be capable ofrapidly applying and maintaining the normal force to within61 % of the specified force.6.5.2 Device for Shearing the SpecimenThis device shallbe capable of shearing the specimen at
42、a uniform rate ofrotation, with less than 65 % deviation. The rate to be applieddepends upon the consolidation characteristics of the soil (see9.5.1). The rate is usually maintained with an electric motorand gear box arrangement.6.6 Shear Force Measurement Device, two proving rings,load cells, in co
43、mbination with a lever arm or a torquetransducers accurate to measure a force of 0.2 N (0.05 lbf).6.7 Water Bath, container for the shear device and waterneeded to inundate the specimen.6.8 Controlled High-Humidity EnviromentFor preparingthe specimen, such that the water content gain or loss durings
44、pecimen rehydration is minimized.6.9 Deformation IndicatorsDial gage, or other suitabledevice, capable of measuring the change in thickness of thespecimen, with a sensitivity of 0.0025 mm (0.0001 in.). Etchedscale on circumference of the ring base to measure the degreestraveled, and thus the shear d
45、isplacement, or other methodscapable of obtaining a sensitivity of 2.6.10 Equipment for Determination of Water Content, inaccordance in Test Method D2216.6.11 Miscellaneous Equipment, including timing devicewith a second hand, site-specific, test water (distilled ordemineralized), mortar, pestle, sp
46、atulas, razor blades,straightedge, and so forth.7. Test Specimen7.1 The sample used for specimen preparation is to besufficiently large so that a ring shear specimen and specimensfor index property tests can be prepared.7.2 If an intact specimen is desired, the sample obtainedfrom the shear surface
47、should be trimmed to produce anannular specimen. Trimming of specimen can be accomplishedusing an annular trimming ring to facilitate trimming andinsertion of the specimen into the annular specimen container.A field shear surface may consist of small seams of clayeymaterial surrounded by material wi
48、th a coarser gradation. If so,only the clayey shear zone material should be tested and not thecoarser surrounding material to simulate field shearing condi-tions. The intact specimen should be trimmed by ensuringminimization of moisture loss or gain.7.3 Reconstituted silt and clay specimens may be p
49、reparedby crushing an air-dried representative sample and passing itthrough the U.S. Standards No. 200 sieve.7.4 Reconstituted specimens of heavily overconsolidatedclays, mudstones, claystones, and shales may be prepared byball-milling an air-dried representative sample and passing itthrough the U.S. Standard No. 200 sieve. The ball-millingfacilitates disaggregation of the clay particles and reduces theshear displacement required to achieve a residual strengthcondition. If ball-milling is not used, greater shear displace-ment will be required to disaggregate t
