Solutions Manual – Principles of Geotechnical Engineering, 10th Edition by Braja Das | All 18 Chapters Covered

,
, Chapter 2

D60 0.42 D302 0.212
2.1 Cu = = = 2.625 ≈ 2.63 ; Cc = = = 0.656 ≈ 0.66
D10 0.16 ( D60 )( D10 ) (0.42)(0.16)


D60 0.81 D302 0.412
2.2 Cu = = = 3.0 ; Cc = = = 0.768 ≈ 0.77
D10 0.27 ( D60 )( D10 ) (0.81)(0.27)


2.3 a.
Sieve Mass of soil retained Percent retained Percent
no. on each sieve (g) on each sieve finer
4 28 4.54 95.46
10 42 6.81 88.65
20 48 7.78 80.88
40 128 20.75 60.13
60 221 35.82 24.31
100 86 13.94 10.37
200 40 6.48 3.89
Pan 24 3.89 0.00
∑ 617 g




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, b. D10 = 0.16 mm; D30 = 0.29 mm; D60 = 0.45 mm

D60 0.45
c. Cu = = = 2.812 ≈ 2.81
D10 0.16

D302 0.292
d. Cc = = = 1.168 ≈ 1.17
( D60 )( D10 ) (0.45)(0.16)



2.4 a.
Sieve Mass of soil retained Percent retained Percent
no. on each sieve (g) on each sieve Finer
4 0 0.0 100.00
6 30 6.0 94.0
10 48.7 9.74 84.26
20 127.3 25.46 58.80
40 96.8 19.36 39.44
60 76.6 15.32 24.12
100 55.2 11.04 13.08
200 43.4 8.68 4.40
Pan 22 4.40 0.00
∑ 500 g




b. D10 = 0.13 mm; D30 = 0.3 mm; D60 = 0.9 mm

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, D60 0 .9
c. Cu = = = 6.923 ≈ 6.92
D10 0.13

D302 0.32
d. Cc = = = 0.769 ≈ 0.77
( D60 )( D10 ) (0.9)(0.13)


2.5 a.
Sieve Mass of soil retained Percent retained Percent
no. on each sieve (g) on each sieve finer
4 0 0.0 100.00
10 40 5.49 94.51
20 60 8.23 86.28
40 89 12.21 74.07
60 140 19.20 54.87
80 122 16.74 38.13
100 210 28.81 9.33
200 56 7.68 1.65
Pan 12 1.65 0.00
∑ 729 g




b. D10 = 0.17 mm; D30 = 0.18 mm; D60 = 0.28 mm

D60 0.28
c. Cu = = = 1.647 ≈ 1.65
D10 0.17
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, D302 0.18 2
d. Cc = = = 0.68
( D60 )( D10 ) (0.28)(0.17)


2.6 a.
Sieve Mass of soil retained Percent retained Percent
no. on each sieve (g) on each sieve finer
4 0 0.0 100.00
6 0 0.0 100.00
10 0 0.0 100.00
20 9.1 1.82 98.18
40 249.4 49.88 48.3
60 179.8 35.96 12.34
100 22.7 4.54 7.8
200 15.5 3.1 4.7
Pan 23.5 4.7 0.00
∑ 500 g




b. D10 = 0.21 mm; D30 = 0.39 mm; D60 = 0.45 mm

D60 0.45
c. Cu = = = 2.142 ≈ 2.14
D10 0.21
D302 0.39 2
d. Cc = = = 1.609 ≈ 1.61
( D60 )( D10 ) (0.45)(0.21)

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,2.7 a.




b. Percent passing 2 mm = 100 GRAVEL: 100 – 100 = 0%
Percent passing 0.06 mm = 73 SAND: 100 – 73 = 27%
Percent passing 0.002 mm = 9 SILT: 73 – 9 = 64%
CLAY: 9 – 0 = 9%

c. Percent passing 2 mm = 100 GRAVEL: 100 – 100 = 0%
Percent passing 0.05 mm = 68 SAND: 100 – 68 = 32%
Percent passing 0.002 mm = 9 SILT: 68 – 9 = 59%
CLAY: 9 – 0 = 9%

d. Percent passing 2 mm = 100 GRAVEL: 100 – 100 = 0%
Percent passing 0.075 mm = 80 SAND: 100 – 80 = 20%
Percent passing 0.002 mm = 9 SILT: 80 – 9 = 71%
CLAY: 9 – 0 = 9%




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,2.8 a.




b. Percent passing 2 mm = 100 GRAVEL: 100 – 100 = 0%
Percent passing 0.06 mm = 30 SAND: 100 – 30 = 70%
Percent passing 0.002 mm = 5 SILT: 70 – 5 = 65%
CLAY: 5 – 0 = 5%

c. Percent passing 2 mm = 100 GRAVEL: 100 – 100 = 0%
Percent passing 0.05 mm = 28 SAND: 100 – 28 = 72%
Percent passing 0.002 mm = 5 SILT: 72 – 5 = 67%
CLAY: 5 – 0 = 5%

d. Percent passing 2 mm = 100 GRAVEL: 100 – 100 = 0%
Percent passing 0.075 mm = 34 SAND: 100 – 34 = 66%
Percent passing 0.002 mm = 5 SILT: 66 – 5 = 61%
CLAY: 5 – 0 = 5%




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,2.9 a.




b. Percent passing 2 mm = 100 GRAVEL: 100 – 100 = 0%
Percent passing 0.06 mm = 84 SAND: 100 – 84 = 16%
Percent passing 0.002 mm = 28 SILT: 84 – 28 = 56%
CLAY: 28 – 0 = 28%

c. Percent passing 2 mm = 100 GRAVEL: 100 – 100 = 0%
Percent passing 0.05 mm = 83 SAND: 100 – 83 = 17%
Percent passing 0.002 mm = 28 SILT: 83 – 28 = 55%
CLAY: 28 – 0 = 28%

d. Percent passing 2 mm = 100 GRAVEL: 100 – 100 = 0%
Percent passing 0.075 mm = 90 SAND: 100 – 90 = 10%
Percent passing 0.002 mm = 28 SILT: 90 – 28 = 62%
CLAY: 28 – 0 = 28%




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, 2.10 a.




b. Percent passing 2 mm = 100 GRAVEL: 100 – 100 = 0%
Percent passing 0.06 mm = 65 SAND: 100 – 65 = 35%
Percent passing 0.002 mm = 35 SILT: 65 – 35 = 30%
CLAY: 35 – 0 = 35%

c. Percent passing 2 mm = 100 GRAVEL: 100 – 100 = 0%
Percent passing 0.05 mm = 62 SAND: 100 – 62 = 38%
Percent passing 0.002 mm = 35 SILT: 62 – 35 = 27%
CLAY: 35 – 0 = 35%

d. Percent passing 2 mm = 100 GRAVEL: 100 – 100 = 0%
Percent passing 0.075 mm = 70 SAND: 100 – 70 = 30%
Percent passing 0.002 mm = 35 SILT: 70 – 35 = 35%
CLAY: 35 – 0 = 35%




2.11 Gs = 2.7; temperature = 24°; time = 60 min; L = 9.2 cm

L (cm)
Eq. (2.5): D (mm) = K
t (min)


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