1、Designation: D3999/D3999M 111Standard Test Methods forthe Determination of the Modulus and Damping Propertiesof Soils Using the Cyclic Triaxial Apparatus1This standard is issued under the fixed designation D3999/D3999M; the number immediately following the designation indicates theyear of original a
2、doption or, in the case of revision, the 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.1NOTEDesignation was editorially corrected to match units information in October
3、2013.1. Scope*1.1 These test methods cover the determination of themodulus and damping properties of soils in either intact orreconstituted states by either load or stroke controlled cyclictriaxial techniques. The standard is focused on determiningthese properties for soils in hydrostatically consol
4、idated,undrained conditions.1.2 The cyclic triaxial properties of initially saturated orunsaturated soil specimens are evaluated relative to a numberof factors including: strain level, density, number of cycles,material type, and effective stress.1.3 These test methods are applicable to both fine-gr
5、ainedand coarse-grained soils as defined by the unified soil classi-fication system or by Practice D2487. Test specimens may beintact or reconstituted by compaction in the laboratory.1.4 Two test methods are provided for using a cyclic loaderto determine the secant Youngs modulus (E) and dampingcoef
6、ficient (D) for a soil specimen. The first test method (A)permits the determination of E and D using a constant loadapparatus. The second test method (B) permits the determina-tion of E and D using a constant stroke apparatus. The testmethods are as follows:1.4.1 Test Method AThis test method requir
7、es the appli-cation of a constant cyclic load to the test specimen. It is usedfor determining the secant Youngs modulus and dampingcoefficient under a constant load condition.1.4.2 Test Method BThis test method requires the appli-cation of a constant cyclic deformation to the test specimen. Itis use
8、d for determining the secant Youngs modulus anddamping coefficient under a constant stroke condition.1.5 The development of relationships to aid in interpretingand evaluating test results are left to the engineer or officerequesting the test.1.6 LimitationsThere are certain limitations inherent inus
9、ing cyclic triaxial tests to simulate the stress and strainconditions of a soil element in the field during an earthquake,with several summarized in the following sections. With dueconsideration for the factors affecting test results, carefullyconducted cyclic triaxial tests can provide data on the
10、cyclicbehavior of soils with a degree of accuracy adequate formeaningful evaluations of modulus and damping coefficientbelow a shearing strain level of 0.5 %.1.6.1 Nonuniform stress conditions within the test specimenare imposed by the specimen end platens.1.6.2 A 90 change in the direction of the m
11、ajor principalstress occurs during the two halves of the loading cycle onisotropically confined specimens.1.6.3 The maximum cyclic axial stress that can be applied toa saturated specimen is controlled by the stress conditions atthe end of confining stress application and the pore-waterpressures gene
12、rated during undrained compression. For anisotropically confined specimen tested in cyclic compression,the maximum cyclic axial stress that can be applied to thespecimen is equal to the effective confining pressure. Sincecohesionless soils cannot resist tension, cyclic axial stressesgreater than thi
13、s value tend to lift the top platen from the soilspecimen. Also, as the pore-water pressure increases duringtests performed on isotropically confined specimens, the effec-tive confining pressure is reduced, contributing to the tendencyof the specimen to neck during the extension portion of theload c
14、ycle, invalidating test results beyond that point.1.6.4 While it is advised that the best possible intactspecimens be obtained for cyclic testing, it is sometimesnecessary to reconstitute soil specimens. It has been shown thatdifferent methods of reconstituting specimens to the samedensity may resul
15、t in significantly different cyclic behavior.Also, intact specimens will almost always be stronger andstiffer than reconstituted specimens of the same density.1.6.5 The interaction between the specimen, membrane, andconfining fluid has an influence on cyclic behavior. Membranecompliance effects cann
16、ot be readily accounted for in the testprocedure or in interpretation of test results. Changes in1These test methods are under the jurisdiction ofASTM Committee D18 on Soiland Rock and are the direct responsibility of Subcommittee D18.09 on Cyclic andDynamic Properties of Soils.Current edition appro
17、ved Nov. 1, 2011. Published January 2012. Originallyapproved in 1991. Last previous edition approved in 2003 as D399991 (2003).DOI: 10.1520/D3999-11E01.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken
18、, PA 19428-2959. United States1pore-water pressure can cause changes in membrane penetra-tion in specimens of cohesionless soils. These changes cansignificantly influence the test results.1.7 The values stated in either SI units or inch-pound unitspresented in brackets are to be regarded separately
19、asstandard. The values stated in each system may not be exactequivalents; therefore, each system shall be used independentlyof the other. Combining values from the two systems mayresult in non-conformance with the standard. Reporting of testresults in units other than SI shall not be regarded as non
20、con-formance with this test method.1.8 All observed and calculated values shall conform to theguide for significant digits and rounding established in PracticeD6026. The procedures in Practice D6026 that are used tospecify how data are collected, recorded, and calculated areregarded as the industry
21、standard. In addition, they are repre-sentative of the significant digits that should generally beretained. The procedures do not consider material variation,purpose for obtaining the data, special purpose studies, or anyconsiderations for the objectives of the user. Increasing orreducing the signif
22、icant digits of reported data to be commen-surate with these considerations is common practice. Consid-eration of the significant digits to be used in analysis methodsfor engineering design is beyond the scope of this standard.1.8.1 The method used to specify how data are collected,calculated, or re
23、corded 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 results obtained using thisstandard is beyond its scope.1.9 This standard does not purport to address all of thesafety concerns, if any, associated wit
24、h its use. It is theresponsibility of the user of this standard 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 Terminolog
25、y Relating to Soil, Rock, and ContainedFluidsD854 Test Methods for Specific Gravity of Soil Solids byWater PycnometerD1587 Practice for Thin-Walled Tube Sampling of Soils forGeotechnical PurposesD2216 Test Methods for Laboratory Determination of Water(Moisture) Content of Soil and Rock by MassD2435
26、Test Methods for One-Dimensional ConsolidationProperties of Soils Using Incremental LoadingD2487 Practice for Classification of Soils for EngineeringPurposes (Unified Soil Classification System)D2488 Practice for Description and Identification of Soils(Visual-Manual Procedure)D3740 Practice for Mini
27、mum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD4220 Practices for Preserving and Transporting SoilSamplesD4318 Test Methods for Liquid Limit, Plastic Limit, andPlasticity Index of SoilsD4767 Test Method for Consolidate
28、d Undrained TriaxialCompression Test for Cohesive SoilsD6026 Practice for Using Significant Digits in GeotechnicalData2.2 USBR Standard:3USBR 5210 Practice for Preparing Compacted Soil Speci-mens for Laboratory Use3. Terminology3.1 Definitions:3.1.1 The definitions of terms used in these test method
29、sshall be in accordance with Terminology D653.3.1.2 back pressurea pressure applied to the specimenpore-water to cause air in the pore space to pass into solutionin the pore-water, that is, to saturate the specimen.3.2 Definitions of Terms Specific to This Standard:3.2.1 cycle durationthe time inter
30、val between successiveapplications of a deviator stress.3.2.2 deviator stress FL2the difference between themajor and minor principal stresses in a triaxial test.3.2.3 effective confining stressthe confining pressure (thedifference between the cell pressure and the pore-water pres-sure) prior to shea
31、ring the specimen.3.2.4 effective force, (F)the force transmitted through asoil or rock mass by intergranular pressures.3.2.5 hysteresis loopa trace of load versus deformationresulting from the application of one complete cycle of eithera cyclic load or deformation. The area within the resulting loo
32、pis due to energy dissipated by the specimen and apparatus, seeFig. 1.3.2.6 load durationthe time interval the specimen issubjected to a cyclic deviator stress.4. Summary of Test Method4.1 The cyclic triaxial test consists of imposing either acyclic axial deviator stress of fixed magnitude (load con
33、trol) orcyclic axial deformation (stroke control) on a cylindrical,hydrostatically consolidated soil specimen in undrained condi-tions. The resulting axial strain and axial stress are measuredand used to calculate either stress-dependent or stroke-dependent secant modulus and damping coefficient.5.
34、Significance and Use5.1 The cyclic triaxial test permits determination of thesecant modulus and damping coefficient for cyclic axial load-ing of a prismatic soil specimen in hydrostatically2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at servic
35、eastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from U.S. Department of the Interior, Bureau of Reclamation, 1849C St NW Washington, DC 20240, http:/www.doi.gov.D3999/D3999M 1112consolidated, undrained conditi
36、ons. The secant modulus anddamping coefficient from this test may be different from thoseobtained from a torsional shear type of test on the samematerial.5.2 The secant modulus and damping coefficient are impor-tant parameters used in dynamic, performance evaluation ofboth natural and engineered str
37、uctures under dynamic or cyclicloads such as caused by earthquakes, ocean wave, or blasts.These parameters can be used in dynamic response analysesincluding, finite elements, finite difference, and linear ornon-linear analytical methods.NOTE 1The quality of the result produced by this standard isdep
38、endent on the competence of the personnel performing it, and thesuitability of the equipment and facilities used. Agencies that meet thecriteria of Practice D3740 are generally considered capable of competentand objective testing/sampling/inspection/etc. Users of this standard arecautioned that comp
39、liance with Practice D3740 does not in itself assurereliable results. Reliable results depend on many factors; Practice D3740provides a means of evaluating some of those factors.6. Apparatus6.1 GeneralIn many ways, triaxial equipment suitable forcyclic triaxial tests is similar to equipment used for
40、 theconsolidated-undrained triaxial compression test (see TestMethod D4767). However, there are special features describedin the following sections that are required to perform accept-able cyclic triaxial tests. A schematic representation of thevarious components comprising a cyclic triaxial test se
41、tup isshown in Fig. 2.6.2 Cyclic Loading Equipment:6.2.1 Cyclic loading equipment used for load controlledcyclic triaxial tests must be capable of applying a uniformsinusoidal load at a frequency within the range of 0.1 to 2 Hz.6.2.2 The equipment must be able to apply the cyclic loadabout an initia
42、l static load on the loading piston.6.2.3 The loading device must be able to maintain uniformcyclic loadings to at least 0.5 % of the double amplitude stress,as defined in Fig. 3. The loading pattern used in this standardshall be harmonic, as shown in Fig. 4(a). Unacceptable loadingpatterns, such as
43、 unsymmetrical compression-extension loadpeaks, nonuniformity of pulse duration, “ringing,” or loadfall-off at large strains are illustrated in Fig. 4(b) to Fig. 4(f).The loading pattern shall be compared to the tolerances shownin Fig. 4 to evaluate if it is acceptable for use in this standard.6.2.4
44、 Cyclic loading equipment used for deformation-controlled cyclic triaxial tests must be capable of applying auniform sinusoidal deformation at a frequency range of 0.1 to2 Hz. The equipment must also be able to apply the cyclicdeformation about either an initial datum point or follow thespecimen as
45、it deforms. The type of apparatus typicallyFIG. 1 Schematic of Typical Hysteresis Loop Generated by Cy-clic Triaxial ApparatusFIG. 2 Schematic Representation of Load or Stroke-Controlled Cyclic Triaxial Test SetupD3999/D3999M 1113employed can range from a simple cam to a closed loopelectro-hydraulic
46、 system.6.3 Triaxial Pressure CellThe primary considerations inselecting the cell are tolerances for the piston, top platen, andlow friction piston seal, as summarized in Fig. 5.6.3.1 Two linear ball bushings or similar bearings should beused to guide the loading piston to minimize friction and toma
47、intain alignment.6.3.2 The loading piston diameter should be large enough tominimize lateral bending. A minimum loading piston diameterof16 the specimen diameter has been used successfully inmany laboratories.6.3.3 The loading piston seal is a critical element in triaxialcell design for cyclic soils
48、 testing if an external load cellconnected to the loading rod is employed. The seal must exertnegligible friction on the loading piston. The maximum accept-able piston friction tolerable without applying load correctionsis commonly considered to be 62 % of the maximum singleamplitude cyclic load app
49、lied in the test, refer to Fig. 3.The useof a seal described in 6.4.8 and by Ladd and Dutko,4and Chan5will meet these requirements.6.3.4 Top and bottom platen alignment is critical to avoidincreasing a nonuniform state of stress in the specimen.Internal tie-rod triaxial cells have worked well at a number oflaboratories. These cells allow the placement of the cell wallafter the specimen is in place between the loading platens.Acceptable limits on platen eccentricity and parallelism areshown in Fig. 6.6.3.5 Since axial loading in cyclic triaxial tests is
copyright@ 2008-2019 麦多课文库（www.mydoc123.com）网站版权所有
备案/许可证编号：苏ICP备17064731号-1