A clay layer of thickenss H has a preconsolidation pressure pc and an initial void ratio e0. The initial effective overburden stress at the mid-height of the layer is p0. At the same location, the increment in effective stress due to applied extrenal load is Δp. The comprssion and swelling indices of the clay are Cc and Cs, respectively. If P0 < Pc

${s_c} = \frac{H}{{1 + {e_0}}}\left[ {{C_c}\log \frac{{{p_c}}}{{{p_0}}} + {C_s}\log \frac{{{P_0} + {{\rm{\Delta }}_p}}}{{{p_c}}}} \right]$

${s_c} = \frac{H}{{1 + {e_0}}}\left[ {{C_c}\log \frac{{{p_0}}}{{{p_c}}} + {C_s}\log \frac{{{P_0} + {{\rm{\Delta }}_p}}}{{{p_c}}}} \right]$$

${s_c} = \frac{H}{{1 + {e_0}}}\left[ {{C_s}\log \frac{{{p_0}}}{{{p_c}}} + {C_c}\log \frac{{{P_0} + {{\rm{\Delta }}_p}}}{{{p_c}}}} \right]$$

${s_c} = \frac{H}{{1 + {e_0}}}\left[ {{C_s}\log \frac{{{p_c}}}{{{p_0}}} + {C_c}\log \frac{{{P_0} + {{\rm{\Delta }}_p}}}{{{p_c}}}} \right]$

Assertion (A): Terzaghi considered only primary consolidation and neglected secondary consolidation in his theory of consolidation.Reason (R): Secondary consolidation begins after the end of the primary consolidation.

Both A and R are true and R is the correct explanation of A

Both A and R are true but R is not the correct explanation of A

Both A and R are true and R is the correct explanation of A

Based on drained triaxial shear tests on sands and clays, the representative variations of volumetric strain (ΔV/V) with the shear strain (γ) is shown in the figure.Choose the CORRECT option regarding the representative behaviour exhibited by Curve P and Curve Q.

Curve P represents dense sand and normally consolidated clay, while Curve Q represents loose sand and overconsolidated clay

Curve P represents loose sand and normally consolidated clay, while urve Q represents dense sand and overconsolidated clay

Curve P represents dense sand and overconsolidated clay, while Curve Q represents loose sand and normally consolidated clay

Curve P represents dense sand and normally consolidated clay, while Curve Q represents loose sand and overconsolidated clay

Curve P represents loos sand and oveconsolidated clay, while Curve Q represents dense sand and normally consolidated clay

Coefficient of consolidation for clays normally

increases with increase in liquid limit

decreases with increase in liquid limit

increases with increase in liquid limit

first increases then decrease with increase in the liquid limit

remains constant at all liquid limits

32 + Mcqs in Consolidation in Civil Engineering Page 1 McqOptions

1.	Clay layer A with single drainage and coefficient of consolidation Cv takes 6 months to achieve 50% consolidation. The time to layer B of the same thickness with double drainage and coefficient of consolidation $\frac{{Cv}}{2}$ to achieve the same degree of consolidation.
A.	3 months
B.	6 months
C.	12 months
D.	24 months
Answer» B. 6 months

Discussion

2.	Oedometer is used to calculate which of the following soil parameter
A.	Compressibility
B.	Permeability
C.	Specific gravity
D.	Particle size analysis
Answer» B. Permeability

Discussion

3.	A clay layer of thickenss H has a preconsolidation pressure pc and an initial void ratio e0. The initial effective overburden stress at the mid-height of the layer is p0. At the same location, the increment in effective stress due to applied extrenal load is Δp. The comprssion and swelling indices of the clay are Cc and Cs, respectively. If P0 < Pc <(P0 + Δp), then the the correct expression to estimate the consolidation settlement (Sc) of the clay layers is
A.	${s_c} = \frac{H}{{1 + {e_0}}}\left[ {{C_c}\log \frac{{{p_c}}}{{{p_0}}} + {C_s}\log \frac{{{P_0} + {{\rm{\Delta }}_p}}}{{{p_c}}}} \right]$
B.	${s_c} = \frac{H}{{1 + {e_0}}}\left[ {{C_c}\log \frac{{{p_0}}}{{{p_c}}} + {C_s}\log \frac{{{P_0} + {{\rm{\Delta }}_p}}}{{{p_c}}}} \right]$$
C.	${s_c} = \frac{H}{{1 + {e_0}}}\left[ {{C_s}\log \frac{{{p_0}}}{{{p_c}}} + {C_c}\log \frac{{{P_0} + {{\rm{\Delta }}_p}}}{{{p_c}}}} \right]$$
D.	${s_c} = \frac{H}{{1 + {e_0}}}\left[ {{C_s}\log \frac{{{p_c}}}{{{p_0}}} + {C_c}\log \frac{{{P_0} + {{\rm{\Delta }}_p}}}{{{p_c}}}} \right]$
Answer» E.

Discussion

4.	Consider the following statements:1. Secondary consolidation of soil follows Terzaghi’s one-dimensional theory of consolidation.2. Consolidation is a function of total stress.3. Even after complete dissipation of excess pore pressure, the soil undergoes a little more consolidation.Which of the above statements is/are correct?
A.	3 only
B.	1 and 2 only
C.	2 and 3 only
D.	1 only
Answer» B. 1 and 2 only

Discussion

5.	In a consolidation test, when the load is changed from 50 kN/m2 to 100 kN/m2, then the void ratio changes from 0.80 to 0.60. The coefficient of compressibility will be:
A.	0.002 m2/kN
B.	0.003 m2/kN
C.	0.001 m2/kN
D.	0.004 m2/kN
Answer» E.

Discussion

6.	For a particular loading Condition unsaturated clay layer undergoes 30% consolidation in a period of 180 days. What would be the additional time required for further 20% consolidation to occur
A.	320 days
B.	220 days
C.	280 days
D.	160 days
Answer» B. 220 days

Discussion

7.	In a tri-axial test carried out on cohesion less soil sample with a cell pressure of 20 kPa, the observed value of applied stress at the point of failure was 40 kPa. The angle of internal friction of the soil is _________.
A.	10°
B.	25°
C.	15°
D.	30°
Answer» E.

Discussion

8.	If the co-efficient of permeability is doubled and the co-efficient of volume compressibility is simultaneously haved, the co-efficient of consolidation
A.	increases by 2 times
B.	decreases by 2 times
C.	increases by 4 times
D.	decreases by 4 times
Answer» D. decreases by 4 times

Discussion

9.	In a saturated clay layer consolidation with single drainage, the initial isochrones is a
A.	triangle
B.	square
C.	rectangle
D.	parabola
Answer» E.

Discussion

10.	For finding out the time ‘t1’ required to achieve 50% consolidation of 1 m thick clayey strata resting on an impermeable rock at the bottom and sandy soil at top, a laboratory consolidation test was carried out, using 1 cm thick sample obtained from the same strata. Time “t12” was taken by it to achieve 25% consolidation, under double drainage conditions in the laboratory.Choose the correct value of the ratio $\frac{t_1}{t_2}$ from the following:
A.	400000
B.	16000
C.	160000
D.	None of these
Answer» D. None of these

Discussion

11.	Consider the following statements:1. Secondary consolidation occurs at constant effective stress.2. Secondary consolidation is related to dissipation of pore water pressure3. Secondary consolidation occurs due to the readjustment of soil skeleton after a disturbance during primary consolidation.4. Rate of secondary consolidation is controlled by the viscous adsorbed layer surrounding clay particle in soil.Which of the above statements are correct?
A.	1, 2 and 3
B.	2, 3 and 4
C.	1, 3 and 4
D.	All of the above
Answer» D. All of the above

Discussion

12.	A clay deposit suffers a total settlement of 5 cm with one-way drainage. With two-way drainage, the total settlement will be
A.	10 cm
B.	2.5 cm
C.	20 cm
D.	5 cm
Answer» E.

Discussion

13.	In an Oedometer apparatus, specimen of fully saturated clay has been consolidated under a vertical pressure of 50 kN/m2 and is presently at equilibrium. The effective stress and pore water pressure immediately on increasing the vertical stress to 150 kN/m2, respectively are
A.	50 kN/m2 and 100 kN/m2
B.	150 kN/m2 and 0
C.	100 kN/m2 and kN/m2
D.	0 and 150 kN/m2
Answer» B. 150 kN/m2 and 0

Discussion

14.	A saturated clay layer with double drainage taken 5 years to attain 90% degree of consolidation under a structure. If the same layer were to be single drained, what would be time (in years) required to attain the same consolidation under the same loading conditions?
A.	10
B.	15
C.	20
D.	25
Answer» D. 25

Discussion

15.	Assume initial void ratio = eo, final void ratio = e, initial pressure = po and final pressure = p. then, what is the value of coefficient of compressibility (av)?
A.	av = (e – eo)/(p – po)
B.	av = (eo – e)/(p – po)
C.	av = (eo – e)/(p0 – p)
D.	av = (eo + e)/(p + po)
Answer» C. av = (eo – e)/(p0 – p)

Discussion

16.	A 1 m thick layer of saturated clay, drained at both faces, settles by 10 cm in one year. If a thin layer of prvious soil is introduced in the middle of this layer, then what will be the period during which the settlement of 10 cm will be compacted?
A.	2 years
B.	0.75 years
C.	0.25 years
D.	3 years
Answer» D. 3 years

Discussion

17.	In soil consolidation, what is the correct sequence of processes which take place after loading?A. Decrease in excess pore pressureB. Increase in total stressC. Development of excess pore pressureD. Increase in effective stressSelect the code for the correct answer from the options given below:
A.	C, B, A, D
B.	B, C, D, A
C.	B, C, A, D
D.	C, B, D, A
Answer» D. C, B, D, A

Discussion

18.	In consolidation testing, what is curve fitting method used to determine?
A.	Time factor
B.	Compression index
C.	Swelling index
D.	Coefficient of consolidation
Answer» E.

Discussion

19.	In a 7 m thick soil stratum, with its initial void ratio of 0.40 the void ratio decreases to 0.30 when the effective pressure on the stratum is increased by 1.0 kg/cm2. The consolidation settlement of the stratum will be
A.	5 cm
B.	50 cm
C.	100 cm
D.	150 cm
Answer» C. 100 cm

Discussion

20.	Consider the following statements:1. Immediate settlement takes place as soon as the load is placed.2. Secondary settlement is significant in the case of organic soil.3. Secondary settlement is estimated based on the ‘void ratio versus time curve’ for a particular load under consolidation test.Which of the above statements are correct?
A.	1 and 2 only
B.	1, 2 and 3
C.	2 and 3 only
D.	1 and 3 only
Answer» C. 2 and 3 only

Discussion

21.	If the pressure acting on the footing is 40kPa, the consolidation settlement of the footing will be____.
A.	0.89 m
B.	None of the above
C.	89.0 mm
D.	8.9 mm
Answer» D. 8.9 mm

Discussion

22.	According to the assumptions of Terzaghi's One-Dimensional Consolidation Theory,which of the following statements is/are incorrect?A. The soil is homogeneous.B. The soil is 100% unsaturated.C. The soil is laterally confined.
A.	B and C
B.	Only A
C.	Only C
D.	Only B
Answer» E.

Discussion

23.	Consider the following statements:1) Secondary consolidation results due to prolonged dissipation of excess hydrostatic pressure2) Primary consolidation happens under expulsion of both air and water from voids in early stages3) Initial consolidation in the case of fully saturated soil mainly due to compression of solid particles4) Primary consolidation happens more quickly in coarse-grained soils than in fine-grained soilsWhich of the above statements are correct?
A.	1 and 2 only
B.	2 and 3 only
C.	3 and 4 only
D.	1 and 4 only
Answer» D. 1 and 4 only

Discussion

24.	Assertion (A): Terzaghi considered only primary consolidation and neglected secondary consolidation in his theory of consolidation.Reason (R): Secondary consolidation begins after the end of the primary consolidation.
A.	A is true but R is false
B.	A is false but R is true
C.	Both A and R are true but R is not the correct explanation of A
D.	Both A and R are true and R is the correct explanation of A
Answer» D. Both A and R are true and R is the correct explanation of A

Discussion

25.	In consolidation testing curve, fitting method is used to determine
A.	compression index
B.	swelling index
C.	coefficient of consolidation
D.	time factor
Answer» D. time factor

Discussion

26.	A clay layer 3m deep is sandwiched by a pervious material. The soil reaches 90% consolidation in 3 years. At another site, the same clay layer is bounded by imperious boundary at the bottom and sand at the top. The time (in years) taken by this layer to rech 90% settlement would be
A.	9
B.	21
C.	18
D.	12
E.	6
Answer» E. 6

Discussion

27.	According to the Soil Mechanics, which type of soil is not fully consolidated under the existing overburden pressure?
A.	Compressed soil
B.	Normally consolidated soil
C.	Under – consolidated soil
D.	Pre – consolidated soil
Answer» D. Pre – consolidated soil

Discussion

28.	For a certain loading condition, a saturated clay layer undergoes 40% consolidation in a period of 178 days. What would be the additional time required for further 20% consolidation to occur?
A.	89 days
B.	222.5 days
C.	267 days
D.	400.5 days
Answer» C. 267 days

Discussion

29.	Based on drained triaxial shear tests on sands and clays, the representative variations of volumetric strain (ΔV/V) with the shear strain (γ) is shown in the figure.Choose the CORRECT option regarding the representative behaviour exhibited by Curve P and Curve Q.
A.	Curve P represents loose sand and normally consolidated clay, while urve Q represents dense sand and overconsolidated clay
B.	Curve P represents dense sand and overconsolidated clay, while Curve Q represents loose sand and normally consolidated clay
C.	Curve P represents dense sand and normally consolidated clay, while Curve Q represents loose sand and overconsolidated clay
D.	Curve P represents loos sand and oveconsolidated clay, while Curve Q represents dense sand and normally consolidated clay
Answer» C. Curve P represents dense sand and normally consolidated clay, while Curve Q represents loose sand and overconsolidated clay

Discussion

30.	Coefficient of consolidation for clays normally
A.	decreases with increase in liquid limit
B.	increases with increase in liquid limit
C.	first increases then decrease with increase in the liquid limit
D.	remains constant at all liquid limits
Answer» B. increases with increase in liquid limit

Discussion

31.	In case of coarse grained sand having high permeability and low plasticity, 95% of consolidation occurs within ______ after application of load.
A.	1 minute
B.	30 minute
C.	1 hour
D.	2 hour
Answer» B. 30 minute

Discussion

32.	A bed consists of compressible clay of 4 m thickness with pervious sand on top and impervious rock at the bottom. In a consolidation test on an undisturbed specimen of clay from this deposit 90% settlement was reached in 4 hours. The specimen was 20 mm thick. The time for the building founded over this deposit to reach 90% of its final settlement will be
A.	91 years
B.	82 years
C.	73 years
D.	64 years
Answer» D. 64 years

Discussion

Explore topic-wise MCQs in Civil Engineering.

Clay layer A with single drainage and coefficient of consolidation Cv takes 6 months to achieve 50% consolidation. The time to layer B of the same thickness with double drainage and coefficient of consolidation \(\frac{{Cv}}{2}\) to achieve the same degree of consolidation.

Oedometer is used to calculate which of the following soil parameter

In a consolidation test, when the load is changed from 50 kN/m2 to 100 kN/m2, then the void ratio changes from 0.80 to 0.60. The coefficient of compressibility will be:

For a particular loading Condition unsaturated clay layer undergoes 30% consolidation in a period of 180 days. What would be the additional time required for further 20% consolidation to occur

In a tri-axial test carried out on cohesion less soil sample with a cell pressure of 20 kPa, the observed value of applied stress at the point of failure was 40 kPa. The angle of internal friction of the soil is _________.

If the co-efficient of permeability is doubled and the co-efficient of volume compressibility is simultaneously haved, the co-efficient of consolidation

In a saturated clay layer consolidation with single drainage, the initial isochrones is a

A clay deposit suffers a total settlement of 5 cm with one-way drainage. With two-way drainage, the total settlement will be

In an Oedometer apparatus, specimen of fully saturated clay has been consolidated under a vertical pressure of 50 kN/m2 and is presently at equilibrium. The effective stress and pore water pressure immediately on increasing the vertical stress to 150 kN/m2, respectively are

A saturated clay layer with double drainage taken 5 years to attain 90% degree of consolidation under a structure. If the same layer were to be single drained, what would be time (in years) required to attain the same consolidation under the same loading conditions?

Assume initial void ratio = eo, final void ratio = e, initial pressure = po and final pressure = p. then, what is the value of coefficient of compressibility (av)?

A 1 m thick layer of saturated clay, drained at both faces, settles by 10 cm in one year. If a thin layer of prvious soil is introduced in the middle of this layer, then what will be the period during which the settlement of 10 cm will be compacted?

In soil consolidation, what is the correct sequence of processes which take place after loading?A. Decrease in excess pore pressureB. Increase in total stressC. Development of excess pore pressureD. Increase in effective stressSelect the code for the correct answer from the options given below:

In consolidation testing, what is curve fitting method used to determine?

In a 7 m thick soil stratum, with its initial void ratio of 0.40 the void ratio decreases to 0.30 when the effective pressure on the stratum is increased by 1.0 kg/cm2. The consolidation settlement of the stratum will be

If the pressure acting on the footing is 40kPa, the consolidation settlement of the footing will be____.

According to the assumptions of Terzaghi's One-Dimensional Consolidation Theory,which of the following statements is/are incorrect?A. The soil is homogeneous.B. The soil is 100% unsaturated.C. The soil is laterally confined.

Assertion (A): Terzaghi considered only primary consolidation and neglected secondary consolidation in his theory of consolidation.Reason (R): Secondary consolidation begins after the end of the primary consolidation.

In consolidation testing curve, fitting method is used to determine

A clay layer 3m deep is sandwiched by a pervious material. The soil reaches 90% consolidation in 3 years. At another site, the same clay layer is bounded by imperious boundary at the bottom and sand at the top. The time (in years) taken by this layer to rech 90% settlement would be

According to the Soil Mechanics, which type of soil is not fully consolidated under the existing overburden pressure?

For a certain loading condition, a saturated clay layer undergoes 40% consolidation in a period of 178 days. What would be the additional time required for further 20% consolidation to occur?

Based on drained triaxial shear tests on sands and clays, the representative variations of volumetric strain (ΔV/V) with the shear strain (γ) is shown in the figure.Choose the CORRECT option regarding the representative behaviour exhibited by Curve P and Curve Q.

Coefficient of consolidation for clays normally

In case of coarse grained sand having high permeability and low plasticity, 95% of consolidation occurs within ______ after application of load.

3.	A clay layer of thickenss H has a preconsolidation pressure pc and an initial void ratio e0. The initial effective overburden stress at the mid-height of the layer is p0. At the same location, the increment in effective stress due to applied extrenal load is Δp. The comprssion and swelling indices of the clay are Cc and Cs, respectively. If P0 < Pc <(P0 + Δp), then the the correct expression to estimate the consolidation settlement (Sc) of the clay layers is
A.	\({s_c} = \frac{H}{{1 + {e_0}}}\left[ {{C_c}\log \frac{{{p_c}}}{{{p_0}}} + {C_s}\log \frac{{{P_0} + {{\rm{\Delta }}_p}}}{{{p_c}}}} \right]\)
B.	\({s_c} = \frac{H}{{1 + {e_0}}}\left[ {{C_c}\log \frac{{{p_0}}}{{{p_c}}} + {C_s}\log \frac{{{P_0} + {{\rm{\Delta }}_p}}}{{{p_c}}}} \right]$\)
C.	\({s_c} = \frac{H}{{1 + {e_0}}}\left[ {{C_s}\log \frac{{{p_0}}}{{{p_c}}} + {C_c}\log \frac{{{P_0} + {{\rm{\Delta }}_p}}}{{{p_c}}}} \right]$\)
D.	\({s_c} = \frac{H}{{1 + {e_0}}}\left[ {{C_s}\log \frac{{{p_c}}}{{{p_0}}} + {C_c}\log \frac{{{P_0} + {{\rm{\Delta }}_p}}}{{{p_c}}}} \right]\)
Answer» E.