Engineering Questions with Answers - Multiple Choice Questions
Consolidation Process – 3
1 - Question
For an ordinary clay of medium to low sensitivity, the value of Cc corresponding to the field consolidation line is roughly equal to __________ the compression index of remolded sample.
a) 1.3
b) 2.3
c) 3.3
d) 4.3
View Answer
Answer: a
Explanation: For an ordinary clay of medium to low sensitivity, the value of Cc corresponding to the field consolidation line is roughly equal to 1.3 times the compression index of remolded sample.
2 - Question
The Cc for ordinary clay of medium to low sensitivity, the value of Cc corresponding to the field consolidation line is given by ______
a) Cc=0.009(wL-10%)
b) Cc=0.007(wL-10%)
c) Cc=0.007(wL-20%)
d) Cc=0.007(wL-30%)
View Answer
Answer: a
Explanation: Skempton conducted consolidation tests on a number of clays from different parts of the world and gave the following expression for the compression index for remoulded sample,
Cc=0.007(wL-10%)
For an ordinary clay of medium to low sensitivity, the value of Cc corresponding to the field consolidation line is roughly equal to 1.3 times the compression index of remolded sample.
∴Cc=0.009(wL-10%) for ordinary soil sample.
3 - Question
The equation for pre-compressed soil given by Hough (1957) is ______
a) Cc=0.009(wL-10%)
b) Cc=0.007(wL-10%)
c) Cc=0.3(e0-0.27)
d) Cc=0.007(wL-30%)
View Answer
Answer: c
Explanation: The equation for pre-compressed soil given by Hough (1957) is,
Cc=0.3(e0-0.27) where e0= in-situ voids ratio.
4 - Question
The coefficient of compressibility av is given by _____________
a) av=−e0Δσ′
b) av=−Δσ′Δe
c) av=-∆e
d) av=−ΔeΔσ‘Answer: d
Explanation: The coefficient of compressibility av is defined as the decrease in voids ratio per unit increase of pressure.
View Answer
Answer: d
Explanation: The coefficient of compressibility av is defined as the decrease in voids ratio per unit increase of pressure.
5 - Question
. For a given difference in pressure, the value of av _______ as pressure increases.
a) increases
b) decreases
c) is same
d) becomes unity
View Answer
Answer: b
Explanation: The coefficient of compressibility av is defined as the decrease in voids ratio per unit increase of pressure. Therefore, for a given difference in pressure, the value of av decreases as pressure increases.
6 - Question
. The coefficient of volume change mv is also known as ______________
a) coefficient of compressibility
b) coefficient of volume compressibility
c) compression index
d) expansion index. The coefficient of volume change mv is also known as ______________
a) coefficient of compressibility
b) coefficient of volume compressibility
c) compression index
d) expansion index
View Answer
Answer: b
Explanation: The coefficient of volume change mv is also known as coefficient of volume compressibility. The compression index is denoted by Cc and the expansion index is denoted by Cs.
7 - Question
The coefficient of volume change mv is given by ______
a) mv=1Δσ′
b) mv=−Δe1+eo
c) mv=−Δe1+eo1Δσ
d) mv=−Δe1+eo1Δσ′Answer: d
Explanation: The coefficient of volume change mv is defined as the change in volume of a soil per unit of initial volume due to a given increase in unit pressure.
∴ mv=−Δe1+eo1Δσ′.
View Answer
Answer: d
Explanation: The coefficient of volume change mv is defined as the change in volume of a soil per unit of initial volume due to a given increase in unit pressure.
∴ mv=−Δe1+eo1Δσ′.The relation between mv and av is __________
a) mv=ave0
b) mv=av1+Δσ′
c) mv=av1+e0
d) mv=1e0av1+e0
8 - Question
The relation between mv and av is __________
a) mv=ave0
b) mv=av1+Δσ′
c) mv=av1+e0
d) mv=1e0av1+e0Answer: c
Explanation: The coefficient of volume change mv is given by,
mv=−Δe1+eo1Δσ′ now substituting av=−ΔeΔσ′,
we get mv=av1+e0.
View Answer
Answer: c
Explanation: The coefficient of volume change mv is given by,
mv=−Δe1+eo1Δσ′ now substituting av=−ΔeΔσ′,
we get mv=av1+e0.
9 - Question
When the soil is laterally confined, the changes in volume is ______
a) proportional to change in thickness ∆H
b) inversely proportional to change in thickness ∆H
c) equal to change in thickness ∆H
d) does not depend upon the thickness
View Answer
Answer: a
Explanation: When the soil is laterally confined, there is decrease in the volume. Since the soil is laterally confined, there will be change of volume only due to the decrease in the thickness which implies to the changes in volume is proportional to change in thickness ∆H. The coefficient of volume change with respect to thickness is given by ______
a) mv=H1Δσ′
b) mv=−ΔHH0
c) mv=−ΔHH01e
d) mv=−ΔHH01Δσ′
10 - Question
The coefficient of volume change with respect to thickness is given by ______
a) mv=H1Δσ′
b) mv=−ΔHH0
c) mv=−ΔHH01e
d) mv=−ΔHH01Δσ′
View Answer
Answer: d
Explanation: When the soil is laterally confined, there is decrease in volume due to the decrease in the thickness of the sample.
∴ mv=−Δe1+eo1Δσ′=−ΔHH01Δσ′
Hence mv=−ΔHH01Δσ′.
11 - Question
The change in thickness due to pressure increment is given by ______
a) ∆H = -mv Ho ∆σ’
b) ∆H = -mv ∆σ’
c) ∆H = -mv Ho
d) ∆H = -Ho ∆σ’
View Answer
Answer: a
Explanation: The coefficient of volume change with respect to thickness is given by,
mv=−ΔHH01Δσ′
therefore, the The change in thickness due to pressure increment is given by,
∆H = -mv Ho ∆σ’.
12 - Question
. The minus sign in the change expression for change in thickness ∆H = -mv Ho ∆σ’ denotes ______
a) thickness decreases with increase in pressure
b) thickness decreases with decrease in pressure
c) thickness increases with increase in pressure
d) thickness does not changewith increase in pressure
View Answer
Answer: a
Explanation: The minus sign in the change expression for change in thickness ∆H = -mvHo∆σ’ denotes that with the applied load, the thickness of the soil layer decreases. Thus, in the expression minus sign denotes that thickness decreases with increase in pressure.
13 - Question
The consolidation settlement can be computed by ______
a) using coefficient of volume change only
b) using voids ratio only
c) using both Using coefficient of volume change and voids ratio
d) using compression index only
View Answer
Answer: c
Explanation: The consolidation settlement can be computed by the following methods:
- using coefficient of volume change
- using voids ratio.
14 - Question
The consolidation settlement ρf for a soil stature of thickness H that has fully consolidated index, a pressure increment ∆σ’ with respect to mv is given by ____________
a) ρf=mv H
b) ρf=H∆σ’
c) ρf=mv H∆σ’
d) ρf=mv ∆σ’
View Answer
Answer: c
Explanation: Since the change in thickness is given by,
∆H= -mvHo∆σ’,
The consolidation settlement ρf for a soil stature of thickness H that has fully consolidated index, a pressure increment ∆σ’ with respect to mv is given by,
ρf=mv H∆σ’.
15 - Question
. In practical case under a finite surface loading the intensity σ’ ______ with depth of layer.
a) decreases
b) increases
c) remains constant
d) has negligible effect
View Answer
Answer: a
Explanation: In practical case under a finite surface loading the intensity σ’ decreases with depth of layer. In theoretical case, the pressure increment is transmitted uniformly over a thickness H of the soil layer.