1、Designation: D2166 06D2166/D2166M 13Standard Test Method forUnconfined Compressive Strength of Cohesive Soil1This standard is issued under the fixed designation D2166;D2166/D2166M; the number immediately following the designation indicatesthe year of original adoption or, in the case of revision, th
2、e 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. Scope*1.1 This test method covers the determination of the unconfined compressive strength of cohesive soil in the in
3、tact, remolded,or reconstituted condition, using strain-controlled application of the axial load.1.2 This test method provides an approximate value of the strength of cohesive soils in terms of total stresses.1.3 This test method is applicable only to cohesive materials which will not expel or bleed
4、 water (water expelled from the soildue to deformation or compaction) during the loading portion of the test and which will retain intrinsic strength after removal ofconfining pressures, such as clays or cemented soils. Dry and crumbly soils, fissured or varved materials, silts, peats, and sandscann
5、ot be tested with this method to obtain valid unconfined compression strength values.NOTE 1The determination of the unconsolidated, undrained strength of cohesive soils with lateral confinement is covered by Test Method D2850.1.4 This test method is not a substitute for Test Method D2850.1.5 All obs
6、erved and calculated values shall conform to the guidelines for significant digits and rounding established in PracticeD6026., unless superseded by this standard.1.5.1 The procedures used to specify how data are collected/recorded and calculated in this test method are regarded as theindustry standa
7、rd. In addition, they are representative of the significant digits that should generally be retained. The proceduresused do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the usersobjectives; and it is common practice to increase o
8、r reduce significant digits of reported data to commensurate with theseconsiderations. It is beyond the scope of this test method to consider significant digits used in analysis methods for engineeringdesign.1.6 The values stated in either SI units or inch-pound units are to be regarded separately a
9、s the standard. The values stated ininch-pound units are approximate.each system may not be exact equivalents; therefore, each system shall be used independentlyof the other. Combining values from the two systems may result in non-conformance with the standard.1.6.1 The gravitational system of inch-
10、pound 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 in the engineering/const
11、ruction profession to concurrently use pounds to represent both a unit ofmass (lbm) and of force (lbf). This implicitly combines two separate systems of units; that is, the absolute system and thegravitational system. It is scientifically undesirable to combine the use of two separate sets of inch-p
12、ound units within a singlestandard. As stated, this standard includes the gravitational system of inch-pound units and does not use/present the slug unit formass. However, the use of balances or scales recording pounds of mass (lbm) or recording density in lbm/ft3 shall not be regardedas nonconforma
13、nce with this standard.1.7 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior t
14、o use.2. Referenced Documents2.1 ASTM Standards:2D653 Terminology Relating to Soil, Rock, and Contained Fluids1 This test method is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.05 on Strength andCompressibility of Soils.Current ed
15、ition approved July 15, 2006May 15, 2013. Published January 2007August 2013. Originally approved in 1963. Last previous edition approved in 20002006 asD2166 0006.e1. DOI: 10.1520/D2166-06.10.1520/D2166_D2166M-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Cust
16、omer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to th
17、e previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary
18、of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1D854 Test Methods for Specific Gravity of Soil Solids by Water PycnometerD1587 Practice for Thin-Walled Tube Sampling of Soils for G
19、eotechnical PurposesD2216 Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by MassD2488 Practice for Description and Identification of Soils (Visual-Manual Procedure)D2850 Test Method for Unconsolidated-Undrained Triaxial Compression Test on Cohesive SoilsD3740
20、Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used inEngineering Design and ConstructionD4220 Practices for Preserving and Transporting Soil SamplesD4318 Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of SoilsD6026 Practic
21、e for Using Significant Digits in Geotechnical DataD6913 Test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve AnalysisD7263 Test Methods for Laboratory Determination of Density (Unit Weight) of Soil SpecimensE177 Practice for Use of the Terms Precision and Bias in ASTM Test M
22、ethodsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method3. Terminology3.1 DefinitionsRefer to Terminology D653 for standard definitions of terms.3.1 Definitions:3.1.1 For definitions of common technical terms in this standard, refer to Terminology D653.
23、3.2 Definitions of Terms Specific to This Standard:3.2.1 unconfined compressive strength (qu) )the compressive stress at which an unconfined cylindrical specimen of soil willfail in a simple compression test. Intest; in this test method, unconfined compressive strength is taken as the maximum load a
24、ttainedper 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 shear strength (su)for unconfined compressive strength test specimens, the shear strength is calculated to be 12 of thecompressive stress at failure, as defined in 3
25、.2.1.4. Summary of Test Method4.1 In this test method, a cylindrical soil specimen is unconfined laterally while loaded axially at an axial strain rate between0.5 to 2 %/min. Measurements are made of elapsed time, axial deformation, and axial load. The unconfined compressive stress,qu, is calculated
26、 as the compressive stress at failure. The shear strength, su, is one half of the unconfined compressive strength.5. Significance and Use5.1 The primary purpose of the unconfined compression test is to quickly obtain a measure of compressive strength for thosesoils that possess sufficient cohesion t
27、o permit testing in the unconfined state.5.2 Samples of soils having slickensided or fissured structure, samples of some types of loess, very soft clays, dry and crumblysoils and varved materials, or samples containing significant portions of silt or sand, or both (all of which usually exhibit cohes
28、iveproperties), frequently display higher shear strengths when tested in accordance with Test Method D2850. Also, unsaturated soilswill usually exhibit different shear strengths when tested in accordance with Test Method D2850.5.3 If tests on the same sample in both its intact and remolded states ar
29、e performed, the sensitivity of the material can bedetermined. This method of determining sensitivity is suitable only for soils that can retain a stable specimen shape in the remoldedstate.NOTE 2For soils that will not retain a stable shape, a vane shear test or Test Method D2850 can be used to det
30、ermine sensitivity.NOTE 3The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of theequipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and obj
31、ectivetesting/sampling/inspection. Users of this standard are cautioned that compliance with Practice D3740 does not in itself ensure reliable results. Reliableresults depend on many factors; Practice D3740 provides a means of evaluating some of those factors.6. Apparatus6.1 Compression Device, Devi
32、ceThe compression device may be a platform weighing scale equipped with a screw-jack-activated load yoke, a hydraulic loading device, or any other compression device with sufficient capacity and control to providethe rate of loading prescribed in 7.18.1. For soil with an unconfined compressive stren
33、gth of less than 100 kPa (1.0 ton/ft The 2)the compression device shall be capable of measuring the compressive stress to three significant digits at the maximum stress, orwithin 1 kPa (0.01 ton/ft 0.01 ton/ft2). For soil with an unconfined compressive strength of 100 kPa (1.0 ton/ft , whichever isl
34、arger.2) or greater, the compression device shall be capable of measuring the compressive stress to the nearest 5 kPa (0.05 ton/ft 2).6.2 Sample Extruder, capable of extruding the soil core from the sampling tube at a uniform rate in the same direction of travelin which the sample entered the tube,
35、and with negligible disturbance of the sample. Conditions at the time of sample removal maydictate the direction of removal, but the principal concern is to reduce the potential for additional disturbance beyond that incurredduring initial sampling.D2166/D2166M 1326.3 Deformation Indicator, Indicato
36、rThe deformation indicator shall be a dial indicator graduated to 0.03 mm (0.001in.)0.001 in. or better and having a travel range of at least 20 % of the length of the test specimen, or some other measuringdevice, such as an electronic deformation measuring device, meeting these requirements.6.4 Dia
37、l Comparator, or other suitable device, for measuring the physical dimensions of the specimen to within 0.1 % of themeasured dimension.NOTE 4Vernier calipers are not recommended for soft specimens, which will deform as the calipers are applied on the specimen.6.5 Timer, TimerA timing device indicati
38、ng the elapsed testing time to the nearest second shall be used for establishing therate of strain application prescribed in 7.18.1.6.6 Balance, BalanceThe balance used to weigh specimens shall determine the mass of the specimen to within 0.1 % of itstotal mass.6.7 Equipment, as specified in Test Me
39、thod D2216.6.8 Miscellaneous Apparatus, including specimen trimming and carving tools, remolding apparatus, water content cans, anddata sheets, as required.7. Preparation of Test Specimens7.1 Specimen SizeSpecimens shall have a minimum diameter of 30 mm (1.3 in.)1.3 in. and the largest particle cont
40、ainedwithin the test specimen shall be smaller than one tenth of the specimen diameter. For specimens having a diameter of 72 mm (2.8in.)2.8 in. or larger, the largest particle size shall be smaller than one sixth of the specimen diameter. If, after completion of atest on an intact specimen, it is f
41、ound, based on visual observation, that larger particles than permitted are present, indicate thisinformation in the remarks section of the report of test data (Note 5). The height-to-diameter ratio shall be between 2 and 2.5.Determine the average height and diameter of the test specimen using the a
42、pparatus specified in 5.46.4. Take a minimum of threeheight measurements (120 (approximately 120 apart), and at least three diameter measurements at approximately the quarterpoints of the height.NOTE 5If large soil particles are found in the specimen after testing, a particle-size analysis performed
43、 in accordance with Test Method D6913 maybe performed to confirm the visual observation and the results provided with the test report.7.2 Intact SpecimensPrepare intact specimens from large samples or from samples secured in accordance with Practice D1587and preserved and transported in accordance w
44、ith the practices for Group C samples in Practices D4220. Tube specimens may betested without trimming except for the squaring of ends, if conditions of the sample justify this procedure. Handle specimenscarefully to reduce the potential for additional disturbance, changes in cross section, or loss
45、of water content. If compression orany type of noticeable disturbance would be caused by the extrusion device, split the sample tube lengthwise or cut it off in smallsections to facilitate removal of the specimen with minimal disturbance. Prepare carved specimens with minimal disturbance, andwheneve
46、r possible, in a humidity-controlled room. Make every effort to prevent a change in water content of the soil. Specimensshall be of uniform circular cross section with ends perpendicular to the longitudinal axis of the specimen. When carving ortrimming, remove any small pebbles or shells encountered
47、. Carefully fill voids on the surface of the specimen with remolded soilobtained from the trimmings. When pebbles or crumbling result in excessive irregularity at the ends, cap the specimen with aminimum thickness of plaster of paris, hydrostone, or similar material. When sample condition permits, a
48、 vertical lathe that willaccommodate the total sample may be used as an aid in carving the specimen to the required diameter. Where prevention of thedevelopment of appreciable capillary forces is deemed important, seal the specimen with a rubber membrane, thin plastic coatings,or with a coating of g
49、rease or sprayed plastic immediately after preparation and during the entire testing cycle. Determine the massand dimensions of the test specimen. If the specimen is to be capped, its mass and dimensions should be determined beforecapping. If the entire test specimen is not to be used for determination of water content, secure a representative sample oftrimmings for this purpose, placing them immediately in a covered container. The water content determination shall be performedin accordance with Test Method D2216. Initial dry density determination shall
