BS 1377 : 1990 – 2 Determination of particle size distribution, Xác định sự phân bố cỡ hạt

BS 1377 : 1990 – 2 Determination of particle size distribution, Xác định sự phân bố cỡ hạt

9.1 General

Two methods of sieving are specified. Wet sieving is the definitive method applicable to essentially cohesionless soils. Dry sieving is suitable only for soils containing insignificant quantities of silt and clay.

Two methods of determining the size distribution of fine particles down to the clay size by  edimentation are specified, namely the pipette method and the hydrometer method, in both of which the density of the soil suspension at various intervals is measured.

Combined sieving and sedimentation procedures enable a continuous particle size distribution curve of a soil to be plotted from the size of the coarsest particles down to the clay size

BS 1377 : 1990 – 2 Determination of particle size distribution, Xác định sự phân bố cỡ hạt

9.2 Wet sieving method

9.2.1 General.
9.2.2 Apparatus

9.2.2.1 Test sieves having the following aperture sizes:

75 mm, 63 mm, 50 mm, 37.5 mm, 28 mm, 20 mm,

14 mm, 10 mm, 6.3 mm, 5 mm, 3.35 mm, 2 mm,

1.18 mm, 600 µm, 425 µm, 300 µm, 212 µm,

150 µm, 63 µm and appropriate receivers.

9.2.2.2 A balance readable to 1.0 g.

9.2.2.3 A balance readable to 0.1 g.

9.2.3 Sample preparation
9.2.4 Procedure
9.2.5 Calculations and expression of results
9.2.6 Test report.

The test report shall affirm that the test was carried out in accordance with BS 1377-2:1990 and shall include the following information:

  1. a) the method of test used;
  2. b) the particle size distribution curve or the tabulated percentages, as specified in 9.2.5.5;
  3. c) the information required by clause 9 of BS 1377-1:1990.

BS 1377 : 1990 – 2 Determination of particle size distribution, Xác định sự phân bố cỡ hạt

9.3 Dry sieving method

9.3.1 General.

This method covers the quantitative determination of the particle size distribution in a cohesionless soil down to the fine-sand size. This method shall not be used unless it has been shown that for the type of material under test it gives the same results as the method of analysis by wet sieving. In cases of doubt the method shall not be used

9.3.2 Apparatus

9.3.2.1 Test sieves having the following aperture sizes may be used:

75 mm, 63 mm, 50 mm, 37.5 mm, 28 mm, 20 mm,

14 mm, 10 mm, 6.3 mm, 5 mm, 3.35 mm, 2 mm,

1.18 mm, 600 µm, 425 µm, 300 µm, 212 µm,

150 µm, 63 µm and appropriate receivers

 

9.3.2.2 A balance readable to 1.0 g.

9.3.2.3 A balance readable to 0.1 g.

9.3.2.4 Sample dividers, e.g. the multiple slot type (riffle box).

9.3.2.5 A drying oven capable of maintaining a temperature of 105 °C to 110 °C.

9.3.2.6 A tray.

9.3.2.7 A scoop.

9.3.2.8 Sieve brushes.

9.3.2.9 A mechanical sieve shaker (optional).

9.3.3 Sample preparation.
9.3.4 Procedure
9.3.5 Calculations
9.3.6 Test report.

The test report shall affirm that the test was carried out in accordance with BS 1377-2:1990 and shall include the following information.

  1. a) the method of test used;
  2. b) the particle size distribution curve, or the tabulated percentages, as specified in 9.3.5;
  3. c) the information required by clause 9 of BS 1377-1:1990

BS 1377 : 1990 – 2 Determination of particle size distribution, Xác định sự phân bố cỡ hạt

9.4 Sedimentation by the pipette method

9.4.1 General.

This method covers the quantitative determination of the particle size distribution in a soil from the coarse sand size to the clay size (about 2 µm). (See note.) The procedure enables the percentages of coarse, medium and fine silt, and clay, to be determined. These percentages can be linked to the curve obtained by sieving to provide a single curve for the whole material. The analysis of data requires that the particle density of the soil specimen is known or can be assumed. The test as specified is not usually necessary if less than 10 % of the material passes the 63 µm test sieve as specified in 9.2.

9.4.2 Apparatus
9.4.3 Reagents
9.4.4 Calibrations
9.4.4 Calibrations
9.4.6 Procedure
9.4.7 Calculations and expression of results
9.4.8 Test report.

The test report shall affirm that the test was carried out in accordance with BS 1377-2:1990 and shall  include the following information:

  1. a) the method of test used;
  2. b) the results of the sedmination analysis;
  3. c) the results of the sieving analysis, if appropriate;
  4. d) the method of pretreatment;
  5. e) the information required by clause 9 of BS 1377-1:1990

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BS 1377 1990 – 2 Determination of particle size distribution

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