Refer to the soil profile shown in Figure 7.20 a. Calculate and plot the variation of o, u, and or' with depth. b. If the water table rises to the top of the ground surface, what is the change in the effective stress at the bottom of the clay layer? c. How many feet must the groundwater table rise to decrease the effective stress by 300 lbft at the bottom of the clay layer?

Fundamentals of Geotechnical Engineering (MindTap Course List)
5th Edition
ISBN:9781305635180
Author:Braja M. Das, Nagaratnam Sivakugan
Publisher:Braja M. Das, Nagaratnam Sivakugan
Chapter10: Shear Strength Of Soil
Section: Chapter Questions
Problem 10.24CTP
icon
Related questions
Question
Question 7.4
An exploratory drill hole was made in a stiff saturated clay (see Figure 7.21). The sand lay
underlying the clay was observed to be under artesian pressure. Water in the drill hole rose t
height of 18 ft above the top of the sand layer. If an open excavation is to be made in the cl
how deep can the excavation proceed before the bottom heaves?
7.8
e = 0.49
G, = 2.68
15 ft
Groundwater table
12 ft
e = 0.9
G, = 2.75
O Dry Sand N Clay
Figure 7.20
6 Congage Leaning All Dights Reserved. May not he copied caaed er duplicated in whole or in part Due to eleceunicnighs, somerd party cenent may be uppessed from the ellonk andor hapes
deemed that any ppressed content does not materially affea the overali learning espenence (Coagagelearning derves the rgh io enove adduonal content al any unae if suhsrquan nghsa rstoctions r
Transcribed Image Text:An exploratory drill hole was made in a stiff saturated clay (see Figure 7.21). The sand lay underlying the clay was observed to be under artesian pressure. Water in the drill hole rose t height of 18 ft above the top of the sand layer. If an open excavation is to be made in the cl how deep can the excavation proceed before the bottom heaves? 7.8 e = 0.49 G, = 2.68 15 ft Groundwater table 12 ft e = 0.9 G, = 2.75 O Dry Sand N Clay Figure 7.20 6 Congage Leaning All Dights Reserved. May not he copied caaed er duplicated in whole or in part Due to eleceunicnighs, somerd party cenent may be uppessed from the ellonk andor hapes deemed that any ppressed content does not materially affea the overali learning espenence (Coagagelearning derves the rgh io enove adduonal content al any unae if suhsrquan nghsa rstoctions r
7.2
through
to Figure
cases and plot the variations with depth. (ote: y.
weight.)
dry unit weight, and y= saturated unit
Detalls of soll layer
Problem
II
7.2
H, = 2 ft
H,
118 lb/ft
= 4 ft
H, = 6 ft
%3D
Ya = 115 lb/ft
Ysat =
Yzat = 130 Ib/ft
7.3
H, = 9 ft
Ya 100 lb/ft
H, = 21 ft
122 lb/ft
H, = 36 ft
128 lb/ft
%3D
Ysat
Yint
7.4 Refer to the soil profile shown in Figure 7.20
a. Calculate and plot the variation of o, u, and or' with depth.
b. If the water table rises to the top of the ground surface, what is the change in the effective
stress at the bottom of the clay layer?
c. How many feet must the groundwater table rise to decrease the effective stress by 300 lbft
at the bottom of the clay layer?
7.5 The soil profile at a site consists of 10 m of gravelly sand underlain by a soft clay layer. The
water table lies 1 m below the ground level. The moist and saturated unit weights of the grav-
elly sand are 17.0 kN/m and 20.0 kN/m. respectively. Due to some ongoing construction
work, it is proposed to lower the water table to 3 m below the ground level. What will be the
change in the effective stress on top of the soft clay layer?
76
Ibr
The depth of water in a lake is 4 m. The soil at the bottom of the lake consists of sandy clay.
The moisture content of the soil was determined to be 25.0%. The specific gravity of the soil
Transcribed Image Text:7.2 through to Figure cases and plot the variations with depth. (ote: y. weight.) dry unit weight, and y= saturated unit Detalls of soll layer Problem II 7.2 H, = 2 ft H, 118 lb/ft = 4 ft H, = 6 ft %3D Ya = 115 lb/ft Ysat = Yzat = 130 Ib/ft 7.3 H, = 9 ft Ya 100 lb/ft H, = 21 ft 122 lb/ft H, = 36 ft 128 lb/ft %3D Ysat Yint 7.4 Refer to the soil profile shown in Figure 7.20 a. Calculate and plot the variation of o, u, and or' with depth. b. If the water table rises to the top of the ground surface, what is the change in the effective stress at the bottom of the clay layer? c. How many feet must the groundwater table rise to decrease the effective stress by 300 lbft at the bottom of the clay layer? 7.5 The soil profile at a site consists of 10 m of gravelly sand underlain by a soft clay layer. The water table lies 1 m below the ground level. The moist and saturated unit weights of the grav- elly sand are 17.0 kN/m and 20.0 kN/m. respectively. Due to some ongoing construction work, it is proposed to lower the water table to 3 m below the ground level. What will be the change in the effective stress on top of the soft clay layer? 76 Ibr The depth of water in a lake is 4 m. The soil at the bottom of the lake consists of sandy clay. The moisture content of the soil was determined to be 25.0%. The specific gravity of the soil
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 4 steps with 1 images

Blurred answer
Similar questions
  • SEE MORE QUESTIONS
Recommended textbooks for you
Fundamentals of Geotechnical Engineering (MindTap…
Fundamentals of Geotechnical Engineering (MindTap…
Civil Engineering
ISBN:
9781305635180
Author:
Braja M. Das, Nagaratnam Sivakugan
Publisher:
Cengage Learning