ASTM D5311 D5311M-2013 Standard Test Method for Load Controlled Cyclic Triaxial Strength of Soil《土壤的负荷控制三向疲劳强度的标准试验方法》.pdf

《ASTM D5311 D5311M-2013 Standard Test Method for Load Controlled Cyclic Triaxial Strength of Soil《土壤的负荷控制三向疲劳强度的标准试验方法》.pdf》由会员分享，可在线阅读，更多相关《ASTM D5311 D5311M-2013 Standard Test Method for Load Controlled Cyclic Triaxial Strength of Soil《土壤的负荷控制三向疲劳强度的标准试验方法》.pdf（14页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: D5311 11D5311/D5311M 13Standard Test Method forLoad Controlled Cyclic Triaxial Strength of Soil1This standard is issued under the fixed designation D5311;D5311/D5311M; 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 cyclic strength (sometimes called the liquefaction potenti

3、al) of saturatedsoils in either intact or reconstituted states by the load-controlled cyclic triaxial technique.1.2 The cyclic strength of a soil is evaluated relative to a number of factors, including: the development of axial strain,magnitude of applied cyclic stress, number of cycles of stress ap

4、plication, development of excess pore-water pressure, and stateof effective stress. A comprehensive review of factors affecting cyclic triaxial test results is contained in the literature (1).21.3 Cyclic triaxial strength tests are conducted under undrained conditions to simulate essentially undrain

5、ed field conditionsduring earthquake or other cyclic loading.1.4 Cyclic triaxial strength tests are destructive. Failure may be defined on the basis of the number of stress cycles required toreach a limiting strain or 100 % pore pressure ratio. See Section 3 for Terminology.1.5 This test method is g

6、enerally applicable for testing cohesionless free draining soils of relatively high permeability. Whentesting well-graded materials, silts, or clays, pore-water pressures monitored at the specimen ends may not represent pore-waterpressure values throughout the specimen. However, this test method may

7、 be followed when testing most soil types if care is takento ensure that problem soils receive special consideration when tested and when test results are evaluated.1.6 The values stated in either SI units or inch-pound units presented in brackets are to be regarded separately as standard.The values

8、 stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other.Combining values from the two systems may result in non-conformance with the standard. Reporting of test results in units otherthan SI shall not be regarded as nonconformance with thi

9、s test method.1.6 All observed and calculated values shall conform to the guide for significant digits and rounding established in PracticeD6026. The procedures in Practice D6026 that are used to specify how data are collected, recorded, and calculated are regardedas the industry standard. In additi

10、on, they are representative of the significant digits that should generally be retained. Theprocedures do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations forthe objectives of the user. Increasing or reducing the significant digits of re

11、ported data to be commensurate with theseconsiderations is common practice. Consideration of the significant digits to be used in analysis methods for engineering designis beyond the scope of this standard.1.6.1 The method used to specify how data are collected, calculated, or recorded in this stand

12、ard is not directly related to theaccuracy to which the data can be applied in design or other uses, or both. How one applies the results obtained using this standardis beyond its scope.1.7 The values stated in either SI units or inch-pound units presented in brackets are to be regarded separately a

13、s standard.The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other.Combining values from the two systems may result in non-conformance with the standard. Reporting of test results in units otherthan SI shall not be regarded as no

14、nconformance with this test method.1.8 This standard does not purport to address all of the safety concerns, 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 regulatorylimitat

15、ions prior to use.1 This test method is under the jurisdiction of ASTM Committee D18 on Soil and Rock and is the direct responsibility of Subcommittee D18.09 on Cyclic and DynamicProperties of Soils.Current edition approved Nov. 1, 2011Nov. 1, 2013. Published January 2012December 2013. Originally ap

16、proved in 1992. Last previous edition approved in 20042011as D531192(2004)D5311 1. DOI: 10.1520/D5311-11. 11. DOI: 10.1520/D5311_D5311M-13.2 The boldface numbers in parentheses refer to a list of references at the end of the text.this standard.This document is not an ASTM standard and is intended on

17、ly to provide the user of an ASTM standard an indication of what changes have been made to the 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 vers

18、ionof the standard as published by ASTM is to be considered the official document.*A Summary 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 States12. Referenced Documents2.1 ASTM Standar

19、ds:3D422 Test Method for Particle-Size Analysis of SoilsD653 Terminology Relating to Soil, Rock, and Contained FluidsD854 Test Methods for Specific Gravity of Soil Solids by Water PycnometerD1587 Practice for Thin-Walled Tube Sampling of Soils for Geotechnical PurposesD2216 Test Methods for Laborato

20、ry Determination of Water (Moisture) Content of Soil and Rock by MassD2850 Test Method for Unconsolidated-Undrained Triaxial Compression Test on Cohesive SoilsD3740 Practice for Minimum Requirements for Agencies Engaged in Testing and/or Inspection of Soil and Rock as Used inEngineering Design and C

21、onstructionD4220 Practices for Preserving and Transporting Soil SamplesD4253 Test Methods for Maximum Index Density and Unit Weight of Soils Using a Vibratory TableD4254 Test Methods for Minimum Index Density and Unit Weight of Soils and Calculation of Relative DensityD4318 Test Methods for Liquid L

22、imit, Plastic Limit, and Plasticity Index of SoilsD4767 Test Method for Consolidated Undrained Triaxial Compression Test for Cohesive SoilsD6026 Practice for Using Significant Digits in Geotechnical Data3. Terminology3.1 Definitions:3.1.1 Definitions for terms used in this test method (including liq

23、uefaction) are in accordance with Terminology D653.3.2 Definitions of Terms Specific to This Standard:3.2.1 full or 100 % pore pressure ratio a condition in which u equals 3c.3.2.2 peak pore pressure ratiothe maximum pore pressure ratio measured during a particular loading sequence.3.2.3 peak (singl

24、e amplitude) strainthe maximum axial strain (from the origin or initial step) in either compression orextension produced during a particular loading sequence.3.2.4 peak to peak (double amplitude) strain the difference between the maximum axial strain in compression and extensionduring a given cycle

25、under cyclic loading conditions.3.2.5 pore pressure ratiothe ratio, expressed as a percentage, of the change of excess pore-water pressure, u, to the effectiveminor principal stress, 3c, at the end of primary consolidation.3.2.6 cyclic stress ratiothe ratio of the applied deviator stress to the effe

26、ctive confining pressure (incorporating changes inexcess pore water pressure) during cyclic loading.4. Summary of Test Method4.1 A cylindrical soil specimen is sealed in a watertight rubber membrane and confined in a triaxial chamber where it issubjected to a confining pressure. An axial load is app

27、lied to the top of the specimen by a load rod.4.2 Specimens are consolidated isotropically (equal axial and radial stress). Tubing connections to the top and bottom specimenplatens permit flow of water during saturation, consolidation and measurement of pore-water pressure during cyclic loading.3 Fo

28、r referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandardsvolume information, refer to the standards Document Summary page on the ASTM website.FIG. 1 Schematic Representation of Load-Controlled Cyclic Triax

29、ial Strength Test EquipmentD5311/D5311M 1324.3 Following saturation and consolidation, the specimen is subjected to a sinusoidally varying axial load by means of the loadrod connected to the specimen top platen. The cyclic load, specimen axial deformation, and porewater pressure development withtime

30、 are monitored.4.4 The test is conducted under undrained conditions to approximate essentially undrained field conditions during earthquakeor other dynamic loading. The cyclic loading generally causes an increase in the pore-water pressure in the specimen, resultingin a decrease in the effective str

31、ess and an increase in the cyclic axial deformation of the specimen.4.5 Failure may be defined as when the peak excess pore-water pressure equals the initial effective confining pressure, full or100 % pore pressure ratio (sometimes called initial liquefaction), or in terms of a limiting cyclic strai

32、n or permanent strain.5. Significance and Use5.1 Cyclic triaxial strength test results are used for evaluating the ability of a soil to resist the shear stresses induced in a soilmass due to earthquake or other cyclic loading.5.1.1 Cyclic triaxial strength tests may be performed at different values

33、of effective confining pressure on isotropicallyconsolidated specimens to provide data required for estimating the cyclic stability of a soil.5.1.2 Cyclic triaxial strength tests may be performed at a single effective confining pressure, usually equal to 100 kN/m2(14.514.5 lb/in.2), or alternate pre

34、ssures as appropriate on isotropically consolidated specimens to compare cyclic strength resultsfor a particular soil type with that of other soils, Ref (2).5.2 The cyclic triaxial test is a commonly used technique for determining cyclic soil strength.5.3 Cyclic strength depends upon many factors, i

35、ncluding density, confining pressure, applied cyclic shear stress, stress history,grain structure, age of soil deposit, specimen preparation procedure, and the frequency, uniformity, and shape of the cyclic waveform. Thus, close attention must be given to testing details and equipment.5.4 There are

36、certain limitations inherent in using cyclic triaxial tests to simulate the stress and strain conditions of a soil elementin the field during an earthquake.5.4.1 Nonuniform stress conditions within the test specimen are imposed by the specimen end platens. This can cause aredistribution of void rati

37、o within the specimen during the test.5.4.2 A 90 change in the direction of the major principal stress occurs during the two halves of the loading cycle onisotropically consolidated specimens.5.4.3 The maximum cyclic shear stress that can be applied to the specimen is controlled by the stress condit

38、ions at the end ofconsolidation and the pore-water pressures generated during testing. For an isotropically consolidated contractive (volumedecreasing) specimen tested in cyclic compression, the maximum cyclic shear stress that can be applied to the specimen is equalto one-half of the initial total

39、axial pressure. Since cohesionless soils are not capable of taking tension, cyclic shear stresses greaterthan this value tend to lift the top platen from the soil specimen. Also, as the pore-water pressure increases during tests performedon isotropically consolidated specimens, the effective confini

40、ng pressure is reduced, contributing to the tendency of the specimento neck during the extension portion of the load cycle, invalidating test results beyond that point.5.4.4 While it is advised that the best possible intact specimens be obtained for cyclic strength testing, it is sometimes necessary

41、to reconstitute soil specimens. It has been shown that different methods of reconstituting specimens to the same density may resultin significantly different cyclic strengths. Also, intact specimens will almost always be stronger than reconstituted specimens.5.4.5 The interaction between the specime

42、n, membrane, and confining fluid has an influence on cyclic behavior. Membranecompliance effects cannot be readily accounted for in the test procedure or in interpretation of test results. Changes in porewaterpressure can cause changes in membrane penetration in specimens of cohesionless soils. Thes

43、e changes can significantly influencethe test results.5.4.6 The mean total confining pressure is asymmetric during the compression and extension stress application when thechamber pressure is constant. This is totally different from the symmetric stress in the simple shear case of the level groundli

44、quefaction.NOTE 1The 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 objectivete

45、sting/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliableresults depend on many factors; Practice D3740 provides a means of evaluating some of those factors.6. Apparatus6.1 In many ways, triaxial equip

46、ment suitable for cyclic triaxial strength tests is similar to equipment used for theunconsolidated-undrained triaxial compression test (see Test Method D2850) and the consolidated-undrained triaxial compressiontest (see Test Method D4767). However, there are special features described in the follow

47、ing subsections that are required toperform acceptable cyclic triaxial tests. A schematic representation of a typical load-controlled cyclic triaxial strength test set-upis shown in Fig. 1.6.2 Triaxial Compression CellThe primary considerations in selecting the cell are tolerances for the piston, to

48、p cap, and lowfriction piston seal.D5311/D5311M 1336.2.1 Two linear ball bushings or similar bearings shall be used to guide the load rod to minimize friction and to maintainalignment.6.2.2 The load rod diameter shall be large enough to minimize lateral bending.Aminimum load rod diameter of 16 the s

49、pecimendiameter has been used successfully in many laboratories.6.2.3 The load rod seal is a critical element in triaxial cell design for cyclic soils testing. The seal must exert negligible frictionon the load rod. The maximum acceptable piston friction tolerable without applying load corrections is commonly considered tobe 6 2 % 62 % of the maximum single amplitude cyclic load applied in the test. The use of an air bushing as proposed in Ref(3) will meet or exceed these requirements.6.2.4 Top and bottom platen alignment is critical if premature specim