Designation: D2166/D2166M − 13
Standard Test Method for
Unconfined Compressive Strength of Cohesive Soil1 This standard is issued under the fixed designation D2166/D2166M; 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.
1. Sco Scope* pe* 1.1 This test method covers covers the determination determination of the uncon uncon-fined fin ed co comp mpre ress ssiv ivee str stren engt gth h of co cohe hesi sive ve so soil il in th thee in inta tact, ct, remolded, remold ed, or recon reconstituted stituted condition, using strain strain-contr -controlled olled application of the axial load. 1.2 This test method provides provides an approximate approximate value of the strength of cohesive soils in terms of total stresses. 1.3 This test method is applicable applicable only to cohesive cohesive materials which will not expel or bleed water (water expelled from the soill due to def soi deform ormatio ation n or com compac pactio tion) n) dur during ing the loa loadin ding g portion of the test and which will retain intrinsic strength after remova rem ovall of con confini fining ng pre pressu ssures res,, suc such h as clay clayss or cem cemente ented d soils. Dry and crumbly soils, fissured or varved materials, silts, peats, and sands cannot be tested with this method to obtain valid unconfined compression strength values. NOTE 1—The determination of the unconsolidated, undrained strength of cohesive soils with latera laterall confin confinement ement is covered by Test Method D2850.. D2850
1.4 Thi Thiss tes testt met method hod is not a sub substit stitute ute for Test Method Method D2850.. D2850 1.5 All observed observed and calculated values values shall conform conform to the guidelines guidel ines for signifi significant cant digits and rounding established established in Practice D6026 D6026,, unless superseded by this standard. 1.5.1 The procedures used to specify how data are collected/ recorded and calculated in this test method are regarded as the industry standard. In addition, they are representative of the significant digits that should generally be retained. The procedures dur es use used d do not con consid sider er mate materia riall var variati iation, on, pur purpos posee 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 of reported data to commensurate with these considerations. It is beyond the scope of this test method to consider significant digits used in analysis methodss for engin method engineering eering design. 1.6 The values stated in either SI units or inch-pound inch-pound units are to be regarded separately as standard. The values stated in
each system may not be exa exact ct equ equiva ivalen lents; ts; ther therefo efore, re, eac each h system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. 1.6.1 The gravitational gravitational system of inch-p inch-pound ound 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. 1.6.2 It is common practice practice in the engineering/con engineering/construct struction ion profession to concurrently use pounds to represent both a unit of mass (lbm) and of force (lbf). This implicitly combines two separate systems of units; that is, the absolute system and the gravitationall system gravitationa system.. It is scientifi scientifically cally undesirable undesirable to combine the use of two separate sets of inch-p inch-pound ound units within a single standar stan dard. d. As sta stated ted,, this stan standar dard d incl include udess the gra gravit vitatio ational nal system of inch-pound units and does not use/present the slug unit for mass. However, the use of balances or scales recording pounds of mass (lbm) or recording density in lbm/ft 3 shall not be regarded as nonconformance with this standard. 1.7 This standar standard d doe doess not purport purport to add addre ress ss all of the safetyy pr safet prob oblem lems, s, if an anyy, as asso socia ciate ted d wit with h it itss us use. e. It is th thee responsibility of the user of this standard to establish appro priate safety and health practices and determine the applicability of regulatory limitations prior to use. 2. Referenc Referenced ed Documents 2.1 ASTM Standards:2 D653 Termino D653 erminology logy Relating to Soil, Rock, and Contain Contained ed Fluids D854 Test Methods for Specific Gravity of Soil Solids by D854 Water Pycnometer D1587 Practice D1587 Practice for Thin-Walled Tube Sampling of Soils for Geotechnical Purposes D2216 Test D2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass D2488 Practic D2488 Practicee for Descri Description ption and Ident Identification ification of Soils (Visual-Manual Procedure)
1
This test method is under the jurisdiction jurisdiction of ASTM Committee D18 Committee D18 on on Soil and Rock and is the direc directt respo responsibi nsibility lity of Subc Subcommitt ommittee ee D18.05 on Strength and Compressibility of Soils. Current Curre nt editi edition on appro approved ved May 15, 2013. Publi Published shed August 2013. Origin Originally ally approved in 1963. Last previous edition approved in 2006 as D2166 – 06. DOI:
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at
[email protected]. For Annual Book of ASTM Standards volume information, refer to the standard’s Document Summary page on
10.1520/D2166_D2166M-13.
the ASTM website.
2
*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
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D2166/D2166M − 13
D2850 Test Method for Unconsolidated-Undrained Triaxial D2850 Compression Test on Cohesive Soils D3740 Practic D3740 Practicee for Minimu Minimum m Requir Requirements ements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used in Engineering Design and Construction D4220 Pra D4220 Practic ctices es for Pre Preser servin ving g and Tr Trans anspor portin ting g Soil Samples D4318 Test D4318 Test Met Method hodss for Liq Liquid uid Limi Limit, t, Pla Plastic stic Lim Limit, it, and Plasticity Index of Soils D6026 D6026 Practice Data Practice for Using Significant Digits in Geotechnical D6913 Test D6913 Test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve Analysis D7263 Test D7263 Test Methods for Laboratory Determination of Density (Unit Weight) of Soil Specimens E177 Practice for Use of the Terms Precision and Bias in E177 ASTM Test Methods E691 Practic E691 Practicee for Conducting an Interl Interlaborat aboratory ory Study to Determine the Precision of a Test Method 3. Terminology 3.1 Definitions: 3.1.1 3.1 .1 For defi definiti nitions ons of com common mon technical technical ter terms ms in thi thiss standard, refer to Terminology D653 Terminology D653.. 3.2 Definitions of compr Termsessive Specific tongth This(q Standard: 3.2.1 unconfined unconfined compressive strength stre the compr compresesu)— the sive stress at which an unconfined cylindrical specimen of soil will fail in a sim simple ple compress compression ion test; in thi thiss test method, method, unconfined compressive strength is taken as the maximum load attained per unit area or the load per unit area at 15 % axial strain, whichever is secured first during the performance of a test. 3.2.2 she f or unc unconfi onfined ned com compre pressi ssive ve shear ar str streng ength th (su)— for strength test specimens, the shear strength is calculated to be 1 ⁄ 2 of the compressive stress at failure, as defined in 3.2.1 3.2.1.. 4. Summ Summary ary of Test Test Method 4.1 In th 4.1 this is tes testt me meth thod od,, a cy cyli lind ndri rica call so soil il sp speci ecime men n is unconfined laterally while loaded axially at an axial strain rate between 0.5 to 2 %/min. Measurements are made of elapsed time, axial deformation, and axial load. The unconfined compressive stress, qu, is calculated as the compressive stress at failure. The shear strength, su, is one half of the unconfined compressive strength. 5. Sign Significan ificance ce and Use 5.1 The primary purpose purpose of the unconfined compression test is to qui quickly ckly obtain obtain a mea measur suree of com compre pressi ssive ve str streng ength th for those soils that possess sufficient cohesion to permit testing in the unconfined state. 5.2 Samples 5.2 Samples of so soils ils ha havi ving ng sli slicke ckens nside ided d or fiss fissur ured ed structure, samples of some types of loess, very soft clays, dry and crumbly soils and varved materials, or sample sampless contai containing ning significant portions of silt or sand, or both (all of which usually exhibitt cohesi exhibi cohesive ve prope properties) rties),, frequ frequently ently display higher shear strengths streng ths when tested in accord accordance ance with Test Method D2850 Method D2850.. Also,, uns Also unsatur aturated ated soi soils ls will usu usually ally exh exhibit ibit dif differ ferent ent she shear ar strengths streng ths when tested in accord accordance ance with Test Method D2850 Method D2850..
5.3 If te 5.3 test stss on th thee sa same me sa samp mple le in bo both th it itss in inta tact ct an and d remolded states are performed, the sensitivity of the material can be determined. This method of determining sensitivity is suitable only for soils that can retain a stable specimen shape in the remolded state. NOTE 2—For soils that will not retain a stable shape, a vane shear test or Test Method D2850 Method D2850 can can be used to determine sensitivity. NOTE 3—The 3—The qu qual ality ity of th thee re resu sult lt pr prod oduc uced ed by th this is st stan anda dard rd is depend dep endent ent on the com compet petenc encee of the per person sonnel nel per perfor formin ming g it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 Practice D3740 are generally considered capable of competent and object objective ive testin testing/sam g/sampling pling/inspe /inspection. ction. Users of this standard are cautioned cautio ned that compl compliance iance with Pract Practice ice D3740 D3740 does does not in itself ensure reliable reliab le resul results. ts. Reliable results depen depend d on many factors; Practice D3740 Practice D3740 provides a means of evaluating some of those factors.
6. Appar Apparatus atus 6.1 Compression Device— The The compression device may be a pla platfo tform rm wei weighi ghing ng sca scale le equ equipp ipped ed wit with h a scr screwew-jac jackkactivated load yoke, a hydraulic loading device, or any other compre com pressio ssion n dev device ice wit with h suf suffficie icient nt cap capacit acity y and con contro troll to provide the rate of loading prescribed in 8.1 8.1.. The compression compression device shall be capable of measuring the compressive stress to three significant digits at the maximum stress, or within 1 kPa [0.01 ton/ft2], whichever is larger. 6.2 Sample Extruder, capable of extruding the soil core from the sampling tube at a uniform rate in the same direction of travel in which the sample entered the tube, and with negligible disturbance of the sample. Conditions at the time of sample removal may dictate the direction of removal, but the principal concern concer n is to reduc reducee the potential for additio additional nal disturbance disturbance beyond that incurred during initial sampling. 6.3 Deformation Indicator— The The deformation indicator shall be a dial indicator graduated to 0.03 mm [0.001 in.] or better and having a travel range of at least 20 % of the length of the test specimen specimen,, or some oth other er mea measur suring ing device, device, suc such h as an electronic electro nic defor deformation mation measuring measuring device device,, meeting these requirements. 6.4 Dial Comparator, or other suitable device, for measuring the physical dimensions dimensions of the specim specimen en to within 0.1 % of the measur measured ed dimens dimension. ion. NOTE 4—Vernier 4—Vernier calipers are not recom recommend mended ed for soft specimens, specimens, which will deform as the calipers are applied on the specimen.
6.5 Timer— A timing device indicating the elapsed testing time to the nearest second shall be used for establishing the rate of strain application prescribed in 8.1 in 8.1.. 6.6 Balance— The The balance used to weigh specimens shall determine the mass of the specimen to within 0.1 % of its total mass. 6.7 Equipment, as specified in Test Method D2216 Method D2216.. 6.8 Miscellaneous Apparatus, including specimen trimming and carving tools, remold remolding ing apparatus, water conten contentt cans, and data sheets, as required. 7. Preparat Preparation ion of Test Test Specimens 7.1 Specimen Size— Specimens Specimens shall have a minimum diameter of 30 mm [1.3 in.] and the largest particle contained within
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D2166/D2166M − 13
thee te test st sp spec ecim imen en sh shal alll be sm smal alle lerr th than an on onee te tent nth h of th thee th specimen diameter. For specimens having a diameter of 72 mm [2.8 in.] or larger, the largest particle size shall be smaller than one sixth of the specimen diameter. If, after completion of a test te st on an in inta tact ct sp spec ecim imen en,, it is fo foun und, d, ba base sed d on vi visu sual al observation obser vation,, that larger particles than permit permitted ted are presen present, t, indicate this information in the remarks section of the report of test te st da data ta (No Note te 5). Th Thee he heig ight ht-t -too-di diam amete eterr ra ratio tio sh shall all be between 2 and 2.5. Determine the average height and diameter
providing it is representative of the failed intact specimen. In the case of failed intact specimens, wrap the material in a thin rubber membrane and work the material thoroughly with the fingers to assure complete remolding. Avoid entrapping air in the spe specim cimen. en. Exe Exerci rcise se car caree to obt obtain ain a uni unifor form m den density sity,, to remold to the same void ratio as the intact specimen, and to pres pr eser erve ve th thee na natu tura rall wa water ter co cont nten entt of th thee so soil. il. Fo Form rm th thee disturbed material into a mold of circular cross section having dimensions dimens ions meeting the requirements requirements of of 7.1 7.1.. After remov removal al
of the test specimen using the apparatus specified in 6.4 6.4.. Take a minimum of three height measurements (approximately 120° apart), and at least three diameter measurements at approximately the quarter points of the height.
from the mold, determine the mass and dimensions of the test specimens.
NOTE 5—If large soil particles are found in the specimen after testing, a particle-size analysis performed in accordance with Test Method D6913 Method D6913 may be per perfor formed med to con confirm firm the vis visual ual obs observ ervati ation on and the res result ultss provided with the test report.
7.2 Intact Specimens— Prepare Prepare intact specimens from large samples or from samples secured in accordance with Practice D1587 and preserved and transported in accordance with the D1587 prac pr actic tices es fo forr Gr Grou oup p C sa samp mple less in Pr Prac actic tices es D4220. D4220. Tube specime spe cimens ns may be test tested ed with without out tri trimmin mming g exc except ept for the squa sq uari ring ng of en ends ds,, if co cond nditi ition onss of th thee sa samp mple le ju just stif ify y th this is procedure. Handle specimens carefully to reduce the potential for additional disturbance, changes in cross section, or loss of water wa ter co cont nten ent. t. If co comp mpre ress ssio ion n or an any y ty type pe of no notic ticea eabl blee disturbance would be caused by the extrusion device, split the sampl sam plee tu tube be len lengt gthw hwise ise or cu cutt it of offf in sm smal alll se sect ctio ions ns to facilitate removal of the specimen with minimal disturbance. Prepar Pre paree car carved ved spe specime cimens ns wit with h min minimal imal dis distur turban bance, ce, and whenever possible, in a humidity-controlled room. Make every effo ef fort rt to pr prev even entt a ch chan ange ge in wa wate terr co cont nten entt of th thee so soil il.. Specimens Specime ns shall be of unifo uniform rm circular cross section with ends perpendicular to the longitudinal axis of the specimen. When carvi car ving ng or tr trim immin ming, g, re remo move ve an any y sm small all pe pebb bble less or sh shell ellss encountered. Carefully fill voids on the surface of the specimen with remolded soil obtained from the trimmings. When pebbles or crumbling result in excessive irregularity at the ends, cap the spec sp ecime imen n wit with h a min minimu imum m th thick ickne ness ss of pl plas aster ter of pa pari ris, s, hydrosto hydro stone, ne, or sim simila ilarr mat materi erial. al. Whe When n sam sample ple con condit dition ion permits, a vertical lathe that will accommodate the total sample may be used as an aid in carving the specimen to the required diameter. Where prevention of the development of appreciable capillary forces is deemed important, seal the specimen with a rubber membrane, thin plastic coatings, or with a coating of grease gre ase or spr spraye ayed d pla plastic stic imme immedia diately tely aft after er pre prepar paratio ation n and duri du ring ng th thee en entir tiree tes testin ting g cy cycle cle.. De Deter termi mine ne th thee ma mass ss an and d dimen di mensio sions ns of th thee te test st sp spec ecime imen. n. If th thee sp speci ecime men n is to be capped, its mass and dimensions should be determined before cappi cap ping ng.. If th thee en entir tiree tes testt sp speci ecime men n is no nott to be us used ed fo forr determination of water content, secure a representative sample of trimmings for this purpose, placing them immediately in a covered container. The water content determination shall be performed in accordance with Test Method D2216 Method D2216.. Initial dry density determination Test Method D7263 Method D7263.. shall be performed in accordance with
7.4 Reconstituted Specimens— Specimens Specimens shall be prepared to the predetermined water content and density prescribed by the individual assigning the test (Note (Note 6). 6). After a specimen is formed, trim the ends perpendicular to the longitudinal axis, remove from the mold, and determine the mass and dimensions of the test specimen. NOTE 6—Experience indicates that it is difficult to compact, handle, and obtain valid results with specimens that have a degree of saturation that is greater than 90 %.
8. Pro Procedu cedure re 8.1 Plac Placee the specime specimen n in the loading loading device so that it is ce cent nter ered ed so on that thee the th botto bo ttom m pl plate aten. n. just Adju Ad just st th thee contact load lo adin ing gwith devi de vice ce carefully upper platen makes the specimen. Zero the deformation indicator or record the initial reading readin g of the electronic electronic deformation deformation device. Apply the load so as to produce an axial strain at a rate of 1 ⁄ 2 to 2 %/min. Record load, loa d, def deform ormatio ation, n, and time val values ues at suf suffficie icient nt int interv ervals als to define the shape of the stress-strain curve (usually 10 to 15 points are sufficient). The rate of strain should be chosen so that the time to failure does not exceed about 15 min (Note ( Note 7). 7). Continue loading until the load values decrease with increasing strain,, or until 15 % strain is reached. Indicate strain Indicate the rate of strain in the report of the test data, as required in 10.3.6 10.3.6.. Determine thee wa th wate terr co cont nten entt of th thee te test st sp spec ecim imen en us usin ing g th thee en enti tire re specimen, unless representative trimmings are obtained for this purpose, as in the case of intact specimens. Indicate on the test report whether the water content sample was obtained before or after the shear test, as required in 10.3.1 in 10.3.1.. NOTE 7—Softer materials that will exhibit larger deformation at failure should be tes should tested ted at a hig higher her rat ratee of str strain ain.. Con Conver versel sely y, sti stifff or bri brittle ttle materials that will exhibit small deformations at failure should be tested at a lower rate of strain.
8.2 Mak Makee a sketch, sketch, or tak takee a photo, photo, of the test specimen specimen at failure showing the slope angle of the failure surface if the angle is measurable. 8.3 A copy copy of a example data sheet sheet is included in Appendix in Appendix X1.. Any data sheet can be used, provided the form contains all X1 the required data. 9. Calc Calculati ulation on 9.1 Calculat Calculatee the axial strain, strain, ε1, to the nearest 0.1 %, for a given applied load, as follows:
7.3 Remolded Specimens— Specimens Specimens may be prepared either from a failed intact specimen or from a disturbed sample, Copyright by ASTM Int'l (all rights reserved); Fri Mar 28 10:13:26 EDT 2014 3 Downloaded/printed by Jerry Sayson (Terra Testing Inc) pursuant to License Agreement. No further reproductions authorized.
ε
1
5
∆ L
L 0
3 100
D2166/D2166M − 13
where: change of specimen specimen as read read from deformati deformation on ∆ L = length change indicator or computed from the electronic device, mm [in.], and L0 = initial length of test test specimen, specimen, mm [in.]. [in.]. 9.2 Calcula Calculate te the average cross-sectio cross-sectional nal area, A, for a given applied load, as follows: A 0
A 5
ε1
S
1 2 100
D
where: A0 = initial initial ave averag ragee cro crossss-sect section ional al are areaa of the specimen, specimen, 2 2 mm [in. ], and strain for the the given given load, expres expressed sed as a percent. percent. ε1 = axial strain 9.3 Calcula Calculate te the compressive compressive stress, σc, to three significant figures or nearest 1 kPa [0.01 ton/ft 2], for a given applied load, as follows: σ
c
5
A ! ~ P / A
where: P = given applie applied d load, load, kN [lbf] [lbf],, A = corre correspond sponding ing average average cross-secti cross-sectional onal area m mm m2 [in.2]. 9.4een Graph— I fssive If desire des d, ss a gra graph ph ate) showin sho theal rela relatio tionsh nship ipbetw between compre com pressi veired, stress stre (ordin (or dinate ) wing andg axi axial strain str ain (ab(ab scissa) may be plotted. Select the maximum value of compressivee str siv stress, ess, or the com compre pressiv ssivee str stress ess at 15 % axi axial al str strain ain,, whic wh iche heve verr is se secu cure red d fir first st,, an and d re repo port rt as th thee un unco confi nfine ned d compressive strength, q u. Whenever it is considered necessary for proper interpretation, include the graph of the stress-strain data as part of the data reported. 9.5 If both the intact and remolded compressive compressive strengths strengths are measured, determine the sensitivity, S T , as follows: S T 5
10.3.4 Average height and diameter of specime 10.3.4 specimen, n, 10.3.5 10.3. 5 Height Height-to-d -to-diameter iameter ratio, 10.3.6 10.3. 6 Average rate of strain to failur failure, e, %, 10.3.7 10.3. 7 Strain at failure, %, 10.3.8 10. 3.8 Liqu Liquid id and pla plastic stic lim limits, its, if det determ ermine ined, d, in acco accorrdance with Test Method D4318 Method D4318,, 10.3.9 10.3. 9 Failure sketch sketch or photo, 10.3.10 10.3. 10 Stress Stress-strain -strain graph, graph, if prepared, 10.3.11 10.3. 11 Sensiti Sensitivity vity,, if determ determined, ined,
q u ~ intact specimen!
10.3.12 10.3. 12 Method D6913 Particlee D6913, Particl size analysis, with Test Method , and if determined, in accordance 10.3.13 Remarks— Note N ote any unu unusua suall con condit dition ionss or oth other er data that would be considered necessary to properly interpret the results obtained, for example, slickensides, stratification, shells, pebbles, roots, or brittleness, the type of failure (that is, bulge, diagonal shear, etc.). 11. Pre Precisi cision on and Bias 11.1 Precision— Criteria Criteria for judging the acceptability of test results obtained by this test method on rigid polyurethane foam (density about 0.09 g/cm3) is given in Table in Table 1. 1. These estimates of pre precisi cision on are based on the res result ultss of the int interla erlabor borato atory ry program conducted by the ASTM Reference Soils and Testing Program.3 The precision estimates will vary with the material/ soil type being tested, and judgement is required when applying these estimates to soil. 11.1.1 11 .1.1 The data data in Table in Table 1 are 1 are based on three replicate tests perfor per formed med by each test lab labora orator tory y. The sin singlegle-ope operat rator or and multilaborato multila boratory ry standa standard rd deviat deviation ion shown in Table 1, 1, Column 4, were obtained in accordance with Practice E691 E691.. Results of two properly conducted tests performed by the same operator
3
Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D18-1014. Contact ASTM Customer Service at
[email protected].
q u ~ remolded specimen! TABLE 1 Summary of Test Results from Each Laboratory (Compressive Strength Data on Rigid Polyurethane Foam (density about 0.09 g/cm 3))
10. Report: Test Test Data Sheet(s)/Form(s) 10.1 10. 1 The methodol methodology ogy used to spe specify cify how data are recorded on the tes corded testt dat dataa she sheet(s et(s)/f )/form orm(s) (s),, as giv given en bel below ow,, is covered in in 1.5 1.5.. 10.2 Record as a minimu minimum m the follow following ing general informainformation (data): 10.2.1 10.2. 1 Ident Identification ification and visual description description of the specimen, including soil classification, symbol, and whether the specimen is intact, remolded, reconstituted, etc. Also include specimen identif iden tifyin ying g inf inform ormatio ation, n, suc such h as pro project ject,, loca location tion,, bor boring ing number, sample number, depth, etc. Visual descriptions shall be made in accordance with Practice D2488 Practice D2488.. 10.3 Record as a minimum the following following test data: 10.3.1 10.3. 1 Initial dry density and water content (specify (specify if the water content specimen was obtained before or after shear, and whether from trimmings or the entire specimen), 10.3.2 10.3. 2 Degre Degreee of saturation (Note (Note 8), 8), if computed, NOTE 8—The 8—The spe specifi cificc gra gravit vity y det determ ermine ined d in acc accord ordanc ancee wit with h Test Method D854 is Method D854 is required for calculation of the degree of saturation.
(1) (2) (3) (4) (5) Number of Acceptable Test Average Standard Triplicate Test Range of Two ParameterA ValueB DeviationC Laboratories ResultsD Single-Operator Results (Wiithin-Laboratory Repeatability): 22 Strength, kPa 989 42 120 22 Strain, % 4.16 0.32 0.9 Multilaboratory Results (Between- Laboratory Reproducibility): 22 Strength, kPa 989 53 150 22 Strain, % 4.16 0.35 1.0 A
Streng Str ength th = peakcompr peakcompress essive ive str stress ess and str strain ain = axi axial al str strain ain at pea peak k com compre pressi ssive ve stress. B The number of significant digits and decimal places presented are representative of the input data. In accordance with Practice D6026 D6026,, the standard deviation and acceptable range of results can not have more decimal places than the input data. C Standard Standa rd deviation is calcul calculated ated in accord accordance ance with Practi Practice ce E691 and is referred to as the 1s 1s limit. limit. D Acceptable range of two results is referred to as the d the d 2s limit. limit. It is calculated as 1.960œ 2· 2· 1 s , as defined by Practice E177 E177.. The difference between two properly conducted conduc ted tests should not exceed this limit. The number of signifi significant cant digits/ decima dec imall pla places ces presented presented is equ equal al to tha thatt pre prescr scribe ibed d by thi this s tes testt met method hod or Practice D6026 Practice D6026.. In addition, the value presented can have the same number of decimal places as the standard deviation, even if that result has more significant digits than the standard deviation.
10.3.3 Unconfined compressive strength and shear strength, strength, Copyright by ASTM Int'l (all rights reserved); Fri Mar 28 10:13:26 EDT 2014 4 Downloaded/printed by Jerry Sayson (Terra Testing Inc) pursuant to License Agreement. No further reproductions authorized.
D2166/D2166M − 13
on the same material, using the same equipment, and in the shortest practical period of time should not differ by more than the single-operator d 2s limits shown in Table in Table 1, 1, Column 5. For definition of d 2s see Footnote D in Table 1. 1. Results of two properly conducted tests performed by different operators and on different days should not differ by more than the multilaboratory d 2s limits shown in Table in Table 1, 1, Column 5.
11.2 Bias— There There is no accepte accepted d reference value for this test method, therefore, bias cannot be determined. 12. Keyw Keywords ords 12.1 coh 12.1 cohesiv esivee soi soil; l; sen sensit sitivit ivity; y; str strain ain-co -contr ntroll olled ed load loading ing;; strength; stress-strain relationships; unconfined compression
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D2166/D2166M − 13 APPENDIX (Nonmandatory Information) X1. EXAMPLE DAT DATA SHEET
X1.1 X1. 1 See See Fig. Fig. X1.1. X1.1.
FIG. X1.1 Example Data Sheet
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Jerry Sayson (Terra Testing Inc) pursuant to License Agreement. No further reproductions authorized.
D2166/D2166M − 13
SUMMARY OF CHANGES Committee D18 has identified the location of selected changes to this standard since the last issue (D2166 – 06) that may impact the use of this standard. (Approved May 15, 2013.) (1) Updated units of measurement in 1.6 1.6 and throughout. (2) Revised Sections Sections 3 and and 10 10.. (3) Added Section Section 4.
(4) Revised Revised 6.1 6.1 to to be consistent with with 9.3 9.3.. (5) Added reference to D7263 D7263 in in Section 2.1 Section 2.1 a and nd 7.2 7.2.. (6) Corrected Corrected 9.2 9.2 for for consistency.
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