Chapter 9
9.1 lb/ft2
Point
σ u σ′
A 0 0 0
B (7)(110) = 770 0 770
C 770 + (12)(121) = 2222 (62.4)(12) = 748.8 1473.2
D 2222 + (6)(118) = 2930 748.8 + (62.4)(6) = 1123.2 1806.8
The plot is given below.
G sγ w ( 2 .69 )( 9 .81)
9.2 γ d (layer 1) = = = 15.52 kN/m 3
1+ e 1 + 0 .7
γ w (G s + e ) ( 9.81)( 2.7 + 0.55 )
γ sat(layer 2) = = = 20.57 kN/m 3
1+ e 1 + 0.55
⎛ 1 .2 ⎞
( 9.81)⎜ + 1 .2 ⎟
γ w (Gs + e ) ⎝ 0 . 38 ⎠ = 19.43 kN/m 3
γ sat(layer 3) = =
1+ e 1 + 1 .2
kN/m2
Point
σ u σ′
A 0 0 0
B (5)(15.52) = 77.6 0 77.6
C 77.6 + (8)(20.57) = 242.16 (9.81)(8) = 78.48 163.68
D 242.16 + (3)(19.43) = 300.45 78.48 + (9.81)(3) = 107.9 192.54
57
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
, The plot is shown below.
9.3 kN/m2
Point
σ u σ′
A 0 0 0
B (3)(16) = 48 0 48
C 48 + (6)(18) = 156 (9.81)(6) = 58.86 97.14
D 156 + (2.5)(17) = 198.5 58.86 + (9.81)(2.5) = 83.38 115.12
The plot is shown below.
9.4 a. Water table drops 2 m within layer 2. Assuming dry condition for 2 m:
G sγ w ( 2.7)( 9.81)
γ d (layer 2) = = = 17.08 kN/m 3
1+ e 1 + 0.55
58
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
9.1 lb/ft2
Point
σ u σ′
A 0 0 0
B (7)(110) = 770 0 770
C 770 + (12)(121) = 2222 (62.4)(12) = 748.8 1473.2
D 2222 + (6)(118) = 2930 748.8 + (62.4)(6) = 1123.2 1806.8
The plot is given below.
G sγ w ( 2 .69 )( 9 .81)
9.2 γ d (layer 1) = = = 15.52 kN/m 3
1+ e 1 + 0 .7
γ w (G s + e ) ( 9.81)( 2.7 + 0.55 )
γ sat(layer 2) = = = 20.57 kN/m 3
1+ e 1 + 0.55
⎛ 1 .2 ⎞
( 9.81)⎜ + 1 .2 ⎟
γ w (Gs + e ) ⎝ 0 . 38 ⎠ = 19.43 kN/m 3
γ sat(layer 3) = =
1+ e 1 + 1 .2
kN/m2
Point
σ u σ′
A 0 0 0
B (5)(15.52) = 77.6 0 77.6
C 77.6 + (8)(20.57) = 242.16 (9.81)(8) = 78.48 163.68
D 242.16 + (3)(19.43) = 300.45 78.48 + (9.81)(3) = 107.9 192.54
57
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
, The plot is shown below.
9.3 kN/m2
Point
σ u σ′
A 0 0 0
B (3)(16) = 48 0 48
C 48 + (6)(18) = 156 (9.81)(6) = 58.86 97.14
D 156 + (2.5)(17) = 198.5 58.86 + (9.81)(2.5) = 83.38 115.12
The plot is shown below.
9.4 a. Water table drops 2 m within layer 2. Assuming dry condition for 2 m:
G sγ w ( 2.7)( 9.81)
γ d (layer 2) = = = 17.08 kN/m 3
1+ e 1 + 0.55
58
© 2014 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part.
