Значение и использование

The gradation of the soil is used for classification in accordance with Practice D2487.

The gradation (particle-size distribution) curve is used to calculate the coefficient of uniformity and the coefficient of curvature.

Selection and acceptance of fill materials are often based on gradation. For example, highway embankments, backfills, and earthen dams may have gradation requirements.

The gradation of the soil often controls the design and quality control of drainage filters, and groundwater drainage.

Selection of options for dynamic compaction and grouting is related to gradation of the soil.

The gradation of a soil is an indicator of engineering properties. Hydraulic conductivity, compressibility, and shear strength are related to the gradation of the soil. However, engineering behavior is dependent upon many factors (such as effective stress, stress history, mineral type, structure, plasticity, and geologic origins) and cannot be based solely upon gradation.

Note 1—The quality of the result produced by these test methods is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of these test methods are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.

Область применения

1.1 Soils consist of particles with various shapes and sizes. This test method is used to separate particles into size ranges and to determine quantitatively the mass of particles in each range. These data are combined to determine the particle-size distribution (gradation). This test method uses a square opening sieve criterion in determining the gradation of soil between the 3-in. (75-mm) and No. 200 (75-µm) sieves.

1.2 The terms, soils and material, are used interchangeably throughout the standard.

1.3 In cases where the gradation of particles larger than 3 in. (75 mm) sieve is required, Test Method D5519 may be used.

1.4 In cases where the gradation of particles smaller than No. 200 (75-µm) sieve is required, Test Method D422 may be used.

1.5 Typically, if the maximum particle size is equal to or less than 4.75 mm (No. 4 sieve), then single-set sieving is applicable. Furthermore, if the maximum particle size is greater than 4.75 mm (No. 4 sieve) and equal to or less than 9.5 mm (³/₈-in sieve), then either single-set sieving or composite sieving is applicable. Finally, if the maximum particle size is equal to or greater than 19.0 mm (³/₄-in sieve), composite sieving is applicable. For special conditions see 10.3.

1.6 Two test methods are provided in this standard. The methods differ in the significant digits recorded and the size of the specimen (mass) required. The method to be used may be specified by the requesting authority; otherwise Method A shall be performed.

1.6.1 Method A—The percentage (by mass) passing each sieve size is recorded to the nearest 1 %. This method must be used when performing composite sieving. For cases of disputes, Method A is the referee method.

1.6.2 Method B—The percentage (by mass) passing each sieve size is recorded to the nearest 0.1 %. This method is only applicable for single sieve-set sieving and when the maximum particle size is equal to or less than the No. 4 (4.75-mm) sieve.

1.7 This test method does not cover, in any detail, procurement of the sample. It is assumed that the sample is obtained using appropriate methods and is representative.

1.8 Sample Processing—Three procedures (moist, air dry, and oven dry) are provided to process the sample to obtain a specimen. The procedure selected will depend on the type of sample, the maximum particle-size in the sample, the range of particle sizes, the initial conditions of the material, the plasticity of the material, the efficiency, and the need for other testing on the sample. The procedure may be specified by the requesting authority; otherwise the guidance given in Section 10 shall be followed.

1.9 This test method typically requires two or three days to complete, depending on the type and size of the sample and soil type.

1.10 This test method is not applicable for the following soils:

1.10.1 Soils containing fibrous peat that will change in particle size during the drying, washing, or sieving procedure.

1.10.2 Soils containing extraneous matter, such as organic solvents, oil, asphalt, wood fragments, or similar items. Such extraneous matter can affect the washing and sieving procedures.

1.10.3 Materials that contain cementitious components, such as cement, fly ash, lime, or other stabilization admixtures.

1.11 This test method may not produce consistent test results within and between laboratories for the following soils and the precision statement does not apply to them.

1.11.1 Friable soils in which the sieving processes change the gradation of the soil. Typical examples of these soils are some residual soils, most weathered shales and some weakly cemented soils such as hardpan, caliche or coquina.

1.11.2 Soils that will not readily disperse such as glauconitic clays or some dried plastic clays.

1.11.3 To test these soils, this test method must be adapted, or altered, and these alterations documented. Depending on the design considerations, a specialized gradation-testing program could be performed. The alterations could require the washing and sieving procedures to be standardized such that each specimen would be processed in a similar manner.

1.12 Some materials that are not soils, but are made up of particles may be tested using this method. However, the applicable sections above should be used in applying this standard.

1.13 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026, unless superseded by this test method.

1.13.1 The procedures used to specify how data are collected/recorded and calculated in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user's objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of these test methods to consider significant digits used in analysis methods for engineering design.

1.14 Units—The dimensional values stated in either SI units or inch-pound units are to be regarded as standard, such as 200-mm or 8-in. diameter sieve. Except, the sieve designations are typically identified using the “alternative” system in accordance with Practice E11, such as 3 in. and No. 200, instead of the “standard” system of 75 mm and 75 µm, respectively. Only the SI units are used for mass determinations, calculations and reported results. However, the use of balances or scales recording pounds of mass (lbm) shall not be regarded as nonconformance with this standard.

1.15 A summary of the symbols used in this test method is given in Annex A1.

1.16 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

1.17 Table of Contents—All tables and figures appear at the end of this standard.

Section Scope1 Method A1.6.1 Method B1.6.2 Sample Processing1.8 Units1.14 Referenced Documents2 ASTM Standards2.1 Terminology3 General3.1 Definitions3.2 Definitions of Terms Specific to This Standard3.3 Summary of Test Method4 Significance and Use5 Apparatus6 Sieves6.1 Standard Sieve Set6.1.1 Washing Sieve, No. 200 (75-μm)6.1.2 Designated Separating Sieve6.1.3 Washing Sink with Spray Nozzle6.2 Mechanical Sieve Shaker6.3 Balances6.4 Drying Oven6.5 Sieving Containers6.6 Specimen Containers6.6.1 Collection/Transfer Device6.6.2 Cumulative Mass Container6.6.3 Sieve Brushes6.7 Miscellaneous Items6.8 Splitter or Riffle Box (optional)6.9 Quartering Accessories (optional)6.10 Mortar and Rubber-Covered Pestle (optional)6.11 Low Temperature Drying Oven (optional)6.12 Ultrasonic Water Bath (optional)6.13 Dispersion Shaker (optional)6.14 Reagents7 Dispersant7.1 Dry Addition7.1.1.1 Solution7.1.1.2 Preparation of Apparatus8 Verification of Sieves8.1 Verification Interval8.1.1 Verification of Mechanical Sieve Shaker and
Standard Shaking Period8.2 Large Mechanical Sieve Shaker8.2.1 Verification Interval8.2.2 Hand Sieve Shaking Procedure8.2.3 Sampling9 General9.1 Sample Sources9.2 Bulk Samples9.2.1 Jar and Small Bag Samples9.2.2 Undisturbed Tube Samples9.2.3 Samples from Prior Testing9.2.4 Specimen10 General10.1 Minimum Mass Requirement10.2 Selection of Sieving Procedure10.3 Single Sieve-Set Sieving10.3.1 Composite Sieving10.3.2 Specimen Procurement10.4 Moist Procedure10.4.1 Air-Dried Procedure10.4.2 Oven-Dried Procedure10.4.3 Discussion on Segregating Soils10.4.4 Specimen Procurement and Processing Requirements10.5 Moist Procedure, Single Sieve-Set Sieving10.5.1 Moist Procedure, Composite Sieving10.5.2 Coarse Portion Acceptable Loss (CP_L)10.5.2.3 Air-Dried Procedure, General10.5.3 Air-Dried Procedure, Single Sieve-Set Sieving10.5.4 Air-Dried Procedure, Composite Sieving10.5.5 Oven-Dried Procedure, General10.5.6 Oven-Dried Procedure, Single Sieve-Set Sieving10.5.7 Oven-Dried Procedure, Composite Sieving10.5.8 Procedure (Sieving)11 General11.1 Mass Measurements11.2 Sieve Overloading11.3 Single Sieve-Set Sieving11.4 Specimen Mass11.4.1 Specimen Dispersion11.4.2 Soaking without a Dispersant11.4.2.1 Soaking with a Dispersant11.4.2.2 Using an Ultrasonic Water Bath11.4.2.3 Washing Specimen11.4.3 General Precautions11.4.3.1 Transfer Specimen11.4.3.2 Washing11.4.3.3 Transfer Washed Specimen11.4.3.4 Dry Sieving11.4.4 Sieve Set11.4.4.1 Mechanical Shaking11.4.4.2 Cumulative Material/Mass Retained11.4.5 First Sieve11.4.5.1 Remaining Sieves11.4.5.2 Composite Sieving, Single Separation11.5 Coarser Portion 11.5.1 Dispersing and Washing11.5.1.1 Dry Sieving Coarser Portion11.5.1.3 Subspecimen from Finer Portion11.5.2 Dispersing and Washing Subspecimen11.5.2.1 Dry Sieving Subspecimen11.5.2.2 Composite Sieving, Double Separation11.6 Separating 1^st Subspecimen11.6.1 Dispersing and Washing 2^nd Coarser Portion11.6.2 Dry Sieving 2^nd Coarser Portion11.6.3 2^nd Subspecimen11.6.4 Dispersing and Washing 2^nd Subspecimen11.6.4.1 Dry Sieving 2^nd Subspecimen11.6.4.2 Calculations12 General12.1 Sieve Overloading12.2 Single Sieve-Set Sieving, Percent Passing12.3 Composite Sieving, Mass of Specimen12.4 Composite Sieving, Single Separation12.5 Composite Sieving, Coarser Portion (CP)12.5.1 CP, Percent Passing12.5.1.1 CP, Composite Sieving Correction
Factor (CSCF)12.5.1.2 CP, Acceptable Loss During Washing
and Sieving12.5.1.3 Composite Sieving, Subspecimen (finer
portion)12.5.2 Percent Passing, Specimen (combined
coarser and finer portions)12.5.2.1 Subspecimen, Acceptable Fractional
Percent Retained12.5.2.2 Percent Passing, Acceptance Criterion12.5.2.3 Finer Portion, Percent Passing (optional)12.5.3 Composite Sieving, Double Separation12.6 1^st Coarser Portion12.6.1 1^st Subspecimen12.6.2 Percent Passing, 2^nd Coarser Portion12.6.2.1 2^nd Coarser Portion, Composite Sieving
Correction Factor (2^ndCSCF)12.6.2.2 2^nd Coarser Portion, Acceptable Loss on
Sieving and Washing12.6.2.3 2^nd Coarser Portion, Acceptable Fractional
Percent Retained12.6.2.4 Percent Passing, Acceptance Criterion12.6.2.5 2^nd Subspecimen12.6.3 Percent Passing, 2^nd Subspecimen12.6.3.1 2^nd Subspecimen, Acceptable Fractional
Percent Retained12.6.3.2 Percent Passing, Acceptance Criterion12.6.3.3 1^st Finer Portion, Percent Passing (optional)12.6.4 2^nd Finer Portion, Composite Sieving
Correction Factor (optional)12.6.4.1 2^nd Finer Portion, Percent Passing for
2^nd Subspecimen (optional)12.6.4.2 Report: Test Data Sheet(s)/Form(s)13 Precision and Bias15 Precision15.1 Precision Data Analysis15.1.1 Calculation of Precision15.1.2 Acceptance Criterion15.1.2.4 Triplicate Test Precision Data (TTPD)15.1.3 TTPDMethod A Repeatability15.1.3.1 TTPD-Method A Reproducibility15.1.3.2 TTPD-Method B Repeatability15.1.3.3 TTPD-Method B Reproducibility15.1.3.4 Single Test Precision Data (STPD)15.1.4 STPD-Method A Reproducibility15.1.4.1 STPD-Method B Reproducibility15.1.4.2 Soils Type15.1.5 Discussion on Precision15.1.6 Bias15.2 Keywords16 ANNEXES SymbolsAnnex A1 Sample to Specimen Splitting/Reduction MethodsAnnex A2 GeneralA2.1 Mechanical SplittingA2.1.1 QuarteringA2.1.2 Miniature Stockpile SamplingA2.1.3 Sample Processing Recommendation Based
on Soil TypeA2.2 Clean Gravel (GW, GP) and Clean Sand
(SW, SP)A2.2.1 Gravel with Fines (GM, GC, GC-GM,
GW-GM, GP-GM, GP-GC)A2.2.2 Sand with Silt Fines (SW-SM, SP-SM,
SM)A2.2.3 Sand with Clay and Silt Fines or Clay
Fines (SW-SC, SP-SC, SC, SC-SM)A2.2.4 Silts with Sand or Gravel, or Both (ML,
MH)A2.2.5 Organic Soils with Sand or Gravel, or
Both (OL, OH)A2.2.6 APPENDIXES Example Test Data Sheets/FormsAppendix X1 GeneralX1.1 Precision: Example CalculationsAppendix X2 GeneralX2.1 TABLES and FIGURES