ASTM D4829-2011 Standard Test Method for Expansion Index of Soils《土壤膨胀指数的标准试验方法》.pdf

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1、Designation: D4829 11Standard Test Method forExpansion Index of Soils1This standard is issued under the fixed designation D4829; 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 parentheses ind

2、icates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method allows for determination of expansionpotential of soils when inundated with distilled water.21.2 This test method provides a simple yet sensit

3、ive methodfor evaluation of expansion potential of soils for practicalengineering applications using an index parameter.1.3 The values stated in SI units are to be regarded as thestandard. The values stated in inch-pound units are approxi-mate.1.4 All observed and calculated values shall conform to

4、theguidelines for significant digits and rounding established inPractice D6026.1.4.1 The method used to specify how data are collected,calculated, or recorded in this standard is not directly related tothe accuracy to which the data can be applied in design or otheruses, or both. How one applies the

5、 results obtained using thisstandard is beyond its scope.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 appro-priate safety and health practices and determine the applica-bili

6、ty of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D653 Terminology Relating to Soil, Rock, and ContainedFluidsD698 Test Methods for Laboratory Compaction Character-istics of Soil Using Standard Effort (12 400 ft-lbf/ft3(600kN-m/m3)D854 Test Methods for Specific Gra

7、vity of Soil Solids byWater PycnometerD2216 Test Methods for Laboratory Determination of Wa-ter (Moisture) Content of Soil and Rock by MassD2435 Test Methods for One-Dimensional ConsolidationProperties of Soils Using Incremental LoadingD3740 Practice for Minimum Requirements for AgenciesEngaged in T

8、esting and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD3877 Test Methods for One-Dimensional Expansion,Shrinkage, and Uplift Pressure of Soil-Lime MixturesD4546 Test Methods for One-Dimensional Swell or Col-lapse of Cohesive SoilsD4753 Guide for Evaluating, Selecting

9、, and SpecifyingBalances and Standard Masses for Use in Soil, Rock, andConstruction Materials TestingD6026 Practice for Using Significant Digits in GeotechnicalDataE11 Specification for Woven Wire Test Sieve Cloth and TestSievesE145 Specification for Gravity-Convection and Forced-Ventilation Ovens3.

10、 Terminology3.1 For common definitions of other terms used in this TestMethod, refer to Terminology D653.3.2 Definitions:3.2.1 scarificationscratching the surface of a compactedlayer to facilitate bonding with the next layer to avoid potentialseparation between compacted layers.3.3 Definitions of Te

11、rms Specific to This Standard:3.3.1 expansion index (EI), n1000 times the differencebetween final and initial height of the specimen divided by theinitial height.4. Summary of Test Method4.1 A specimen is prepared by compacting a test soil into ametal ring at a degree of saturation of 50 6 2 %. The

12、specimenand the ring are then placed in a consolidometer. A verticalconfining pressure of 6.9 kPa (1 lbf/in.2) is applied to thespecimen and the specimen is then inundated with distilledwater. The deformation of the specimen is recorded for 24 h or1This test method is under the jurisdiction ofASTM C

13、ommittee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.05 on Strength andCompressibility of Soils.Current edition approved Nov. 1, 2011. Published December 2011. Originallyapproved in 1995. Last previous edition approved in 2008 as D482908a. DOI:10.1520/D4829-11.2Refer to

14、Anderson, J. N., and Lade, P. V., “The Expansion Index Test,”Geotechnical Testing Journal, Vol 4, No. 2, ASTM, 1981, pp. 5867.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information,

15、 refer to the standards Document Summary page onthe ASTM website.1*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.until the rate of deformation becomes less than 0.005

16、mm/h(0.0002 in./h), whichever occurs first. A minimum recordingtime of3hisrequired.5. Significance and Use5.1 The expansion index, EI, provides an indication ofswelling potential of a soil.5.2 The EI test is not used to duplicate any particular fieldconditions such as soil density, water content, lo

17、ading, in-placesoil structure, or soil water chemistry. However, consistent testconditions are used in preparation of compacted specimenssuch that direct correlation of data can be made.NOTE 1Qualitative classification of potential expansion in a soilbased on EI is provided in Table 1.NOTE 2Notwiths

18、tanding 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 which meet the criteria of PracticeD3740 are generally consider

19、ed 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.5.3 The measurement of the magnitude of one-dim

20、ensionalwetting-induced swell or collapse (hydrocompression) underdifferent vertical (axial) pressures, as well as the magnitude ofswell pressure and the magnitude of free swell, and also thedetermination of data for stress-induced compression followingwetting-induced swell or collapse are covered b

21、y Test MethodsD4546.6. Apparatus6.1 MoldThe mold shall be cylindrical in shape, made ofmetal, and shall have the capacity and dimensions indicated inFig. 1. The mold shall have a detachable collar inscribed witha mark 50.8 mm (2.00 in.) above the base. The lower section ofthe mold is designed to ret

22、ain a removable stainless steel ring25.4 mm (1 in.) in height, 101.9 mm (4.01 in.) in internaldiameter, and not less than 3.10 mm (0.120 in.) in wallthickness.6.2 RammerA metal rammer with a circular face with adiameter of 50.8 mm (2.00 in.) and a mass of 2.5 kg (5.5 lbm)shall be used. The rammer sh

23、all be equipped with a suitablearrangement to control height of drop to a free fall of 304.8 mm6 1.3mm (12 in. 6 0.05 in.) over the top of the soil to becompacted. See Test Methods D698 for further specification ofa suitable rammer.6.3 BalanceAbalance of at least 1000 g capacity meetingthe requireme

24、nts of Guide D4753, Class GP2.6.4 Drying OvenA thermostatically controlled dryingoven (specified in Specification E145) capable of maintaininga temperature of 110 6 5C (230 6 9F) for drying watercontent samples.6.5 Straight EdgeSteel straight edge at least 150 mm (6in.) in length with one beveled ed

25、ge.6.6 SievesA 4.75-mm (No. 4) sieve conforming to therequirements of Specification E11.6.7 Mixing ToolsMiscellaneous tools such as mixingpans, spoons, trowels, spatula, a suitable mechanical device,and so forth for thoroughly mixing the sample of soil withwater.6.8 Loading DeviceA consolidometer or

26、 equivalent load-ing device as described in Test Methods D2435 for supportingand submerging the specimen, for applying a vertical load, andfor measuring the change in height of the specimen. Theconsolidometer ring must be as specified in 6.1.6.9 Porous DisksThe disks shall be smooth ground andfine e

27、nough (Note 3) to minimize intrusion of soil into thedisks. The disk shall reduce false displacements caused byseating of the specimen against the surface of the disk. Suchdisplacements are significant, especially if displacements andapplied vertical pressures are small.NOTE 3A suitable pore size is

28、 10 m.6.9.1 Porous disks shall be air dry.6.9.2 Porous disks shall have a close fit to the consolidom-eter ring to avoid extrusion or punching. Suitable disk dimen-sions are 12.7 mm 6 0.13 mm (0.50 in. 6 0.005 in.) in heightand 101.5 mm 6 0.13 mm (3.995 in. 6 0.005 in.) in diameteror as described in

29、 6.3 of Test Methods D2435.7. Sample Preparation7.1 Preparation for SievingIf the soil sample is dampwhen received from the field, dry it until it becomes friableusing a trowel. Air drying or oven drying at temperaturesbelow 60C (140F) may be used. Thoroughly break up theaggregations in a manner suc

30、h that the natural size of indi-vidual particles is not reduced.NOTE 4If particles larger than 6.35 mm (0.25 in.) are potentiallyexpansive, such as particles of claystone, shale, or weathered volcanicrock, they may be broken down so as to pass the 4.75-mm (No. 4) sieveif this is consistent with use

31、of the soil.7.2 SievingSieve an adequate quantity of the representa-tive soil using the 4.75-mm (No. 4) sieve. Record the percent-age of coarse material retained on the 4.75-mm (No. 4) sieveand discard.7.3 SampleSelect a representative sample of the soil witha mass of approximately 1 kg (2 lbm) or m

32、ore prepared usingthe guidelines in 7.1 and 7.2.8. Specimen Preparation8.1 Water ContentThoroughly mix the selected represen-tative sample with sufficient distilled water to bring the soil toa water content that has a corresponding degree of saturation of50 6 2 % in the compacted condition. After mi

33、xing, take arepresentative sample of the material for determination of thewater content and seal the remainder of the soil in a close-fitting airtight container for a period of at least 16 h. Weigh theTABLE 1 Classification of Potential Expansion of Soils Using EIExpansion Index, EI PotentialExpansi

34、on020 Very Low2150 Low5190 Medium91130 High130 Very HighD4829 112moisture sample immediately, and dry in an oven at 110 6 5C(230 6 9F) for at least 12 h, or in accordance with TestMethods D2216, to a constant mass. The water content sampleshall have a mass of at least 100 g conforming with TestMetho

35、ds D2216. The water content of the trimmings shall bedetermined in accordance with Test Methods D2216 using aresolution of 0.1 % or better.8.2 Specimen CompactionPrepare a specimen by com-pacting the cured soil in the 101.9-mm (4.01-in.) diametermold in two equal layers to give a total compacted dep

36、th of50.8 mm (2 in.). Compact each layer by 15 uniformly distrib-uted blows of the rammer dropping free from a height of 305mm 6 2.5 mm (12 in. 6 0.1 in.) above the top of the soil whena sleeve type rammer is used, or from 305 mm 6 2.5 mm (12in. 6 0.1 in.) above the approximate elevation of each fin

37、allycompacted layer when a stationary mounted type of rammer isused. Scarify the first compacted layer before adding materialfor the second layer using a knife or other suitable object.During compaction rest the mold on a uniform rigid founda-tion, such as provided by a cube of concrete with a mass

38、notless than 90 kg (200 lb).8.3 Specimen TrimmingFollowing compaction, removethe upper and lower portions of the mold from the inner ringand carefully trim the specimen flush with the top and bottomof the ring with a straight edge.8.4 Specimen HeightDetermine the initial height of thespecimen H1, wi

39、th a resolution of 0.03 mm (0.001 in.) similarto the procedure in Section 7 ofTest Methods D3877 or assumeequal to the height of the specimen ring.8.5 Degree of SaturationCalculate the water content inaccordance with Test Methods D2216 and the dry unit weightin accordance with Section 11 of Test Met

40、hods D698. Deter-mine the degree of saturation using the equation providedbelow. If the degree of saturation is not within 50 6 2%,prepare another specimen. Adjust the water content of the newspecimen based on the calculated degree of saturation andprepare the specimen in accordance with 8.1-8.4 to

41、achieve adegree of saturation 50 6 2 %. Increase the water content if thedegree of saturation is less than 50% and decrease the watercontent if the degree of saturation is higher than 50 %.S 5wGsgdGsgw2gd(1)where:S = degree of saturation, %w = water content, %,Gs= specific gravity, use 2.7 unless th

42、e specific gravity isknown to be less than 2.6 or more than 2.8,gw= unit weight of water, 9.79 kN/m3(62.3 lbf/ft3) at 20C(68F), andgd= dry unit weight of compacted soil specimen, kN/m3(lbf/ft3).Use the resolution provided in 8.1 for w. Use a resolution of0.1 kN/m3(0.1 lbf/ft3) or better for gd.NOTE

43、5This standard test method assumes a specific gravity of 2.7,which is typical of soil minerals commonly used for compaction. Inaddition, using an assumed specific gravity value of 2.7 will result in amaximum error of 4 % in the calculated degree of saturation, provided theactual specific gravity is

44、between 2.6 and 2.8. These small errors insaturation with mineral type will cause systematic and small changes inthe EI that are considered equally important to variations caused whendetermining the specific gravity using Test Methods D854.FIG. 1 Mold with Ring for Compaction of Specimen forExpansio

45、n Index TestD4829 1139. Procedure9.1 Place the compacted soil specimen in the ring of aconsolidometer or equivalent loading device with air-driedporous disks placed at the top and bottom ends of thespecimen. Subject the specimen to a total pressure of 6.9 kPa(1 lbf/in.2), including the weight of the

46、 upper porous disk andany unbalanced weight of the loading machine. Allow thespecimen to compress under this pressure for a period of 10min. Subsequent to this initial compression period, obtain theinitial reading (D1) on the consolidometer dial indicator with aresolution of 0.03 mm (0.001 in.) or b

47、etter.9.2 Inundate the specimen with distilled water, obtainingperiodic dial indicator readings, in accordance with TestMethods D2435, for a period of 24 h or until the rate ofexpansion becomes less than 0.005 mm/h (0.0002 in./h).However, in no case shall the sample be inundated andreadings taken fo

48、r less than 3 h.9.3 Remove the specimen from the loading machine afterthe final reading (D2) obtained with a resolution of 0.03 mm(0.001 in.) or better and determine the change in height DH asthe difference between the initial and final reading of the dialindicator. Determine the specimen mass to th

49、e nearest 0.1 g(2.2 3 104lbm).10. Calculation and Report10.1 CalculationCalculate the expansion index, EI,asfollows:EI 5DHH11000 (2)where:DH = change in height, D2D1, mm,H1= initial height, mm,D1= initial dial reading, mm, andD2= final dial reading, mm.Use the resolutions provided in 8.4, 9.1, and 9.3 for H1, D1,and D2, respectively.10.2 Record as a minimum the following general informa-tion (data):10.2.1 Sample/specimen identifying information, such asProject No., Boring No., Sample No., Depth, and so forth.10.2.2 Any special selection an