ASTM D4546-2008 Standard Test Methods for One-Dimensional Swell or Collapse of Cohesive Soils《粘性土的单维膨胀或沉降趋势的标准试验方法》.pdf

《ASTM D4546-2008 Standard Test Methods for One-Dimensional Swell or Collapse of Cohesive Soils《粘性土的单维膨胀或沉降趋势的标准试验方法》.pdf》由会员分享，可在线阅读，更多相关《ASTM D4546-2008 Standard Test Methods for One-Dimensional Swell or Collapse of Cohesive Soils《粘性土的单维膨胀或沉降趋势的标准试验方法》.pdf（9页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: D 4546 08Standard Test Methods forOne-Dimensional Swell or Collapse of Cohesive Soils1This standard is issued under the fixed designation D 4546; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisio

2、n. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 These test methods cover three alternative laboratorymethods for measuring free swell, swell pressure, and themagnitude of one-di

3、mensional swell or collapse of compactedor intact cohesive soils.NOTE 1Refer to Sections 4, 5, 6 and 13.8 to determine the bestmethod for a particular application.1.2 The test methods can be used to measure the magnitudeof one-dimensional wetting-induced swell or collapse (hydro-compression) under d

4、ifferent vertical (axial) pressures, as wellas the magnitude of swell pressure and the magnitude of freeswell. It can also be used to obtain data for stress-inducedcompression following wetting-induced swell or collapse.1.3 The values stated in SI units are to be regarded as thestandard. The values

5、stated in inch-pound units are approxi-mate.1.4 All measured and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D 6026.1.4.1 The method used to specify how data are collected,calculated, or recorded in this standard is not directly related

6、 tothe accuracy to which the data can be applied in design or otheruses. How one applies the results obtained using this standardis 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 s

7、tandard 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:2D 422 Test Method for Particle-Size Analysis of SoilsD 653 Terminology Relating to Soil, Rock, and ContainedFluidsD 698 Tes

8、t Methods for Laboratory Compaction Character-istics of Soil Using Standard Effort (12 400 ft-lbf/ft3(600kN-m/m3)D 854 Test Methods for Specific Gravity of Soil Solids byWater PycnometerD 1557 Test Methods for Laboratory Compaction Charac-teristics of Soil Using Modified Effort (56,000 ft-lbf/ft3(2,

9、700 kN-m/m3)D 1587 Practice for Thin-Walled Tube Sampling of Soilsfor Geotechnical PurposesD 2216 Test Methods for Laboratory Determination of Wa-ter (Moisture) Content of Soil and Rock by MassD 2435 Test Methods for One-Dimensional ConsolidationProperties of Soils Using Incremental LoadingD 3550 Pr

10、actice for Thick Wall, Ring-Lined, Split Barrel,Drive Sampling of SoilsD 3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD 3877 Test Methods for One-Dimensional Expansion,Shrinkage, and Uplift Press

11、ure of Soil-Lime MixturesD 4220 Practices for Preserving and Transporting SoilSamplesD 4318 Test Methods for Liquid Limit, Plastic Limit, andPlasticity Index of SoilsD 4718 Practice for Correction of Unit Weight and WaterContent for Soils Containing Oversize ParticlesD 4753 Guide for Evaluating, Sel

12、ecting, and SpecifyingBalances and Standard Masses for Use in Soil, Rock, andConstruction Materials TestingD 6026 Practice for Using Significant Digits in Geotechni-cal DataE 145 Specification for Gravity-Convection and Forced-Ventilation Ovens3. Terminology3.1 DefinitionsRefer to Terminology D 653

13、for standarddefinitions of terms.3.2 Definitions of Terms Specific to This Standard:3.2.1 collapse or hydrocompression, Lwetting-induceddecrease in height of a soil element or test specimen, Dh.1These test methods are under the jurisdiction ofASTM Committee D18 on Soiland Rock and are the direct res

14、ponsibility of Subcommittee D18.05 on Strength andCompressibility of Soils.Current edition approved Oct. 1, 2008. Published November 2008. Originallyapproved in 1985. Last previous edition approved in 2003 as D 4546 03.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact A

15、STM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, 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 Cons

16、hohocken, PA 19428-2959, United States.3.2.2 collapse or hydrocompression strain%-wetting-induced change in height divided by the height immediatelyprior to wetting, (Dh/h) 3 100.3.2.3 compression, Ldecrease in height of a soil elementor test specimen, Dh, due to wetting (synonymous withhydrocompres

17、sion or collapse), or due to increase in totalstress.3.2.4 free swell, %percent swell, (Dh/h) 3 100, followingabsorption of water at the seating pressure of 1 kPa (20 lbf/ft2).3.2.5 heave (L)increase in vertical height, Dh, of a col-umn of soil of height h following absorption of water.3.2.6 intact

18、specimena test specimen obtained from anatural deposit or from an existing compacted fill or embank-ment using undisturbed sampling equipment.3.2.7 percent heave or settlement, %change in verticalheight divided by the height of a column of soil immediatelybefore wetting; (Dh/h) 3 100.3.2.8 primary s

19、well or collapse, Lamount of swell orcollapse characterized as being completed at the intersection ofthe two tangents to the curve shown in Fig. 1.3.2.9 remolded or compacted specimena test specimencompacted into a mold.3.2.10 secondary swell or collapse, Llong-term swell orcollapse characterized as

20、 the linear portion of the plot shown inFig. 1 following completion of primary swell or collapse.3.2.11 settlement, Ldecrease in vertical height, Dh,ofacolumn of soil of height h.3.2.12 swell, Lincrease in thickness of a soil element or asoil specimen following absorption of water.3.2.13 swell press

21、ure, FL-2the minimum stress required toprevent swelling.4. Summary of Test Methods4.1 The following three alternative test methods require thatsoil specimens be restrained laterally and loaded vertically in aconsolidometer, with access to free water.4.1.1 Method AThis method can be used for measurin

22、gone-dimensional wetting-induced swell or collapse (hydro-compression) strains of compacted or natural soils over a rangeof vertical stresses. Four or more identical specimens areassembled in consolidometer units. Different loads are appliedto different specimens and each specimen is given access to

23、free water until the process of primary swell or collapse iscompleted under a constant vertical total stress. The resultingswell or collapse deformations are measured. The final watercontents and dry densities are also measured. This method canbe referred to as wetting-after-loading tests on multipl

24、e speci-mens. The data from these tests can be used to estimateone-dimensional ground surface heave or settlement. In addi-tion, the magnitude of “Swell Pressure,” the minimum verticalstress required for preventing swell, and the magnitude of freeswell, the swell strain corresponding to a near zero

25、stress of 1kPa (20 lbf/ft2) can be interpreted from the test results.4.1.2 Method BThis method can be used for measuringone-dimensional wetting-induced swell or collapse strain of asingle “intact” specimen of natural soil, or a single “intact”specimen of compacted soil obtained from an existing fill

26、 orembankment. The specimen is loaded to a specific verticalstress, typically the in-situ vertical overburden stress or aparticular design pressure, or 1 kPa (20 lbf/ft2) for measuringthe free swell strain, and then inundated to measure the wettinginduced strain under that particular stress. This me

27、thod can bereferred to as single point wetting-after- loading test on asingle specimen.4.1.3 Method CThis method is for measuring load-induced strains after wetting-induced swell or collapse defor-mation has occurred. This method can be referred to asloading-after-wetting test. The results would app

28、ly to situationswhere new fill and/or additional structural loads are applied tothe ground that has previously gone through wetting-inducedheave or settlement. The first part of the test is the same as inMethod A or B. After completion of the swell or collapsephase, increments of additional vertical

29、 loads are applied to thespecimen in the same manner as in a consolidation test, TestMethods D 2435, and the load-induced deformations are mea-sured.5. Significance and Use5.1 The soil swell/collapse strains measured from these testmethods can be used to develop estimates of heave orsettlement for a

30、 confined soil profile subject to one-dimensional heave or settlement, or stress-induced settlementfollowing wetting-induced heave/settlement. They can also beused to estimate the pressure that would be necessary toprevent swelling. Selection of test method, loading, and inun-dation sequences should

31、, as closely as possible, simulate fieldconditions because relatively small variations in unit weightand water content, or sequence of loading and wetting cansignificantly alter the test results. (See 6.1.8 and Refs (1-5).)3NOTE 2Notwithstanding the statement on precision and bias con-tained in this

32、 standard: The precision of this test method is dependent onthe competence of the personnel performing the test and the suitability ofthe equipment and facilities used. Agencies which meet the criteria ofPractice D 3740 are generally considered capable of competent andobjective testing. Users of thi

33、s test method are cautioned that compliancewith Practice D 3740 does not in itself assure reliable testing. Reliabletesting depends on several factors; Practice D 3740 provides a means ofevaluating some of these factors.3The boldface numbers in parentheses refer to the list of references at the end

34、ofthis standard.FIG. 1 Time-Swell CurveD45460826. Interferences and Limitations6.1 When using data from these test methods, the followinglimitations should be considered:6.1.1 Laboratory one-dimensional tests simulate verticaldeformation with full lateral restraint; they do not simulatelateral colla

35、pse or lateral swell. Therefore, the results shouldnot be used to estimate lateral extension of slopes, differentialheave/settlement in the vicinity of slopes, or differentialheave/settlement where ground surface is not relatively flat.6.1.2 Inundation of specimens in the laboratory represent anextr

36、eme case of wetting and the results represent upper boundvalues for swell/collapse strains, and the degrees of saturationtypically rise to 90-95 % (not 100 %, (1). The wetting situa-tion in the field rarely produces inundation; wetting is oftencaused by water percolation. In-situ water contents and

37、degreesof saturation typically end up being somewhat lower than thosecaused by inundation in the laboratory. Consequently, themagnitudes of swell/collapse strains in the field might besomewhat smaller than those measured in the laboratory.Partial wetting tests can be performed for estimating a parti

38、alwetting reduction factor for use in conjunction with heave/settlement calculations (1).6.1.3 Because laboratory tests are usually performed insmall molds, gravels and other granular inert particles (over-size) are excluded from the specimen. This has two implica-tions: (1) Laboratory specimens sho

39、uld be compacted at matrix(finer fraction) water content and matrix dry density asdescribed in 9.1.2; and (2) Because the test results represent thevolume change behavior of the soils finer fraction, they shouldbe applied only to the soil column consisting of the finerfraction of in the field (exclu

40、ding the oversize inert particles.)This can be done by applying an oversize factor in calculatingthe magnitude of the net ground surface heave or settlement(2).6.1.4 Disturbance of naturally occurring soils, and variabil-ity in composition of “intact” specimens can affect the testresults.6.1.5 Rates

41、 of swell or collapse as measured by laboratorytime rate curves are not always reliable indicators of field ratesof heave/settlement due to soil nonuniformity, fissures orlocalized permeable layers within the soil mass, variability inpercentage of oversize particles, and non-uniform wetting(differen

42、t sources of water, concurrent vertical downwardpercolation and lateral percolation from canyon sides, localizedwetting anomalies due to leaking buried utility lines, cyclicwetting episodes).6.1.6 Secondary long-term swell/collapse may be signifi-cant for some soils and estimates of slow time-depend

43、entsecondary heave/settlement can be added if necessary. This canbe done based on the slope of plot of strain versus Log timeline in Fig. 1.6.1.7 Any differences between the chemical content of thefield water and the water used in the laboratory tests mightinfluence the amount of heave/settlement in

44、 the field.6.1.8 For reliable application of the test results, the stresspath and the wetting sequence should as closely as possiblesimulate field conditions. Because the shape of the wetting-induced strain versus vertical stress curves (Figs. 3-5) forcohesive soils depend on the stress path and the

45、 wettingsequence, loading-after-wetting tests on a single specimen(Method C) should not be expected to give results applicable towetting-after-loading cases (Method A) such as post-construction heave/settlement of compacted fills and embank-ments (1-4). However, it has been found (5) that for noncoh

46、e-sive collapsible soils, loading-after-wetting tests on a singlespecimen can give a segment of the curve (in the vicinity of thestress level at wetting) that is close to the results of a MethodA multiple specimen wetting-after-loading test.7. Apparatus and Materials7.1 ConsolidometerThe apparatus s

47、hall comply with therequirements of Test Methods D 2435. The apparatus shall becapable of exerting a pressure on the specimen of (1) at leastFIG. 2 Deformation versus Vertical Stress, Method AD4546083200 % of the maximum anticipated design pressure, or (2) theswell pressure, whichever is greatest.7.

48、1.1 Consolidometer rigidity influences the test results.Therefore, consolidometers of high rigidity should be used.7.2 Porous StonesThe stones shall be smooth ground andfine enough to minimize intrusion of soil into the stones if filterpaper is not used and shall reduce false displacements causedby

49、seating of the specimen against the surface of porous stones(Note 3). Such displacements may be significant, especially ifdisplacements and applied vertical pressures are small.7.2.1 Porous stones shall be air dry.7.2.2 Porous stones shall fit close to the consolidometer ringto avoid extrusion or punching of the soil specimen at highvertical pressures. Suitable stone dimensions are described in5.3 of Test Methods D 2435.NOTE 3A suitable pore size is 10 m if filter paper is not used. Filterpaper is not recommended because of its high compressibility and sho