Explanation Calculation: For soil A: Determine the fine fraction as shown below. Coarse fraction = Percent passing on No .200 seive (1) Substitute 3 % for percent retained on No.200 sieve in Equation (1). Fine fraction = 3 % Determine the coarse fraction as shown below. Coarse fraction = 100 − Percent passing on No .200 seive (2) Substitute 3 % for percent retained on No.200 sieve in Equation (2). Coarse fraction = 100 − 3 = 9 7 % Determine the gravel fraction as shown below. Gravel fraction = 100 − Percent passing on No .4 seive (3) Substitute 94 % for percent passing No.4 sieve in Equation (3). Gravel fraction = 100 − 94 = 6 % Determine the sand fraction using the relation. Sand fraction = Percent passing on No .4 seive − Percent passing on No .200 seive (4) Substitute 94 % for percent retained on No.4 sieve and 3 % for percent retained on No.200 sieve in Equation (4). Sand fraction = 94 − 3 = 91 % The grains passing through No. 4 Sieve is greater than 50 %. Hence, the soil is a sandy soil. Sketch the grain size distribution curve as shown in Figure 1. Refer to Figure 1. The diameter of the particle corresponding to 60 % finer ( D 60 ) is 1.84 mm . The diameter of the particle corresponding to 30 % finer ( D 30 ) is 0.96 mm . The diameter of the particle corresponding to 10 % finer ( D 10 ) is 0.41 mm . Calculate the uniformity coefficient ( C u ) using the relation. C u = D 60 D 10 (5) Substitute 1.84 mm for D 60 and 0.41 mm for D 10 in Equation (5). C u = 1.84 0.41 = 4.49 Calculate the coefficient of gradation ( C c ) using the relation. C c = D 30 2 D 60 × D 10 (6) Substitute 1.84 mm for D 60 , 0.96 mm for D 30 , and 0.41 mm for D 10 in Equation (6). C c = 0.96 2 1.84 × 0.91 = 1.22 Refer Table 5.2 “Unified soil classification system” in the text book. The group symbol of the soil can be taken as SP _ . Provide the group name of soil as shown below. The gravel fraction 6 % is < 15 % . Refer Figure 5.4 “Flowchart group names for gravelly and sandy soil” in the text book. Take the group name as poorly graded sand for the group of SP and gravel fraction of < 15 % . Thus, the classification of soil A using unified soil classification system is Poorly graded sand _ . For soil B: Determine the fine fraction as shown below. Substitute 10 % for percent retained on No.200 sieve in Equation (1). Fine fraction = 10 % Determine the coarse fraction as shown below. Substitute 10 % for percent retained on No.200 sieve in Equation (2). Coarse fraction = 100 − 10 = 90 % Determine the gravel fraction as shown below. Substitute 98 % for percent passing No.4 sieve in Equation (3). Gravel fraction = 100 − 98 = 2 % Determine the sand fraction using the relation. Substitute 98 % for percent retained on No.4 sieve and 10 % for percent retained on No.200 sieve in Equation (4). Sand fraction = 98 − 10 = 88 % The grains passing through No. 4 Sieve is greater than 50 %. Hence, the soil is a sandy soil. The fine fraction 10 % is lies between 5 % to 12 %. Hence, the symbol of soil is a dual symbol. Refer to Figure 1. The diameter of the particle corresponding to 60 % finer ( D 60 ) is 1.08 mm . The diameter of the particle corresponding to 30 % finer ( D 30 ) is 0.44 mm . The diameter of the particle corresponding to 10 % finer ( D 10 ) is 0

Principles of Geotechnical Engineering (MindTap Course List)

9th Edition

ISBN: 9781305970939

Author: Braja M. Das, Khaled Sobhan

Publisher: Cengage Learning

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Soil classification and characteristics

Soil classification is a method of categorizing soil based on its properties, types, and uses. The motive of soil classification is to arrange various types of soils and divide them into groups for various engineering and agricultural purposes. Soil clas…

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Chapter 5, Problem 5.7P

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Find the classification of the given soil using unified soil classification system and give the group symbols and group names.

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Principles of Geotechnical Engineering (MindTap Course List)

Ch. 5 - Prob. 5.1P Ch. 5 - Prob. 5.2P Ch. 5 - Prob. 5.3P Ch. 5 - Prob. 5.4P Ch. 5 - Prob. 5.5P Ch. 5 - Prob. 5.6P Ch. 5 - Prob. 5.7P Ch. 5 - Prob. 5.8P Ch. 5 - Prob. 5.9P Ch. 5 - Prob. 5.10P

Ch. 5 - The subsurface characteristics for a highway...

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