Download Visvesvaraya Technological University (VTU) BE-B.Tech (Bachelor of Engineering/ Bachelor of Technology) 2020 January [folder1] 4th Sem 15CV45 Basic Geotechnical Engineering Previous Question Paper

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Basic Geotechnical Engineering

USN

15CV45

@M ,M1q2

tr, ,,BRARY

Time: 3 hrs. Max. Marks: 80

ti

U

U

Module-1

? I a. Define : Void ratio , Porosity , Degree of saturation and Air content.

b. Derive the expression for dry density of soil in the form

(1- n

u

)G.

Y

.

Yd

" with usual notations.

)

1 wG

ct ?

7=

c. Define Liquid limit , Relative consistency and Toughness index.

N

c -

P -

C

0

z

2 cs-

OR

2 a. State Stoke's law. List the assumptions (04 Marks)

b. Explain with the help of particle size distribution curves : Well graded soil , Poorly graded

soil and Gap graded soil. (06 Marks)

c. A fully saturated soil sample has a water content of 35% and specific gravity of 2.65.

Determine its porosity , saturated unit weight and dry unit weight. (06 Marks)

Module-2

3 a. What are the different types of clay minerals commonly found in soils? Explain any one

with their structure. (06 Marks)

b. The observations of a standard proctor test are as follows :

Note: Answer any FIVE full questions, choosing ONE full question from each module.

(04 Marks)

(06 Marks)

(06 Marks)

Dry density , KN/m

3

16.16 17.06 18.61 18.95 18.78 17.13

Water content , % 5 8.81 11.25 13.05 14.40 19.25

i) Plot the compaction curve and determine OMC and v

d ma -

ii) Also compute void ratio and degree of saturation at optimum condition. Take G = 2.77.

(10 Marks)

OR

4 a. Differentiate between Standard and Modified Proctor's tests. (04 Marks)

b. Discuss the effect of compaction on different properties of soil. (06 Marks)

c. Explain Electrical diffuse double layer and Adsorbed water. (06 Marks)

Module-3

5 a. Differentiate between : i) Seepage velocity and discharge velocity

ii) Coefficient of permeability and coefficient of percolation. (04 Marks)

b. Derive an expression for the determination of coefficient of permeability by falling head

0

z

permeameter. (06 Marks)

C

c. An earthen dam 300m long is built on an impervious foundation with a horizontal filter

0

under the d/s slope. The horizontal and vertical permeability's of the soil are 5 x 10

-5

m/sec

and 2 x in/sec respectively. The full reservoir level is 20m above the downstream filter.

The flow net consists of 4 flow channels and 16 equipotential drops. Estimate the seepage

loss in litres per day per unit length of the darn. (06 Marks)

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Fourth Semester B.E. Degree Examination,

\.r-

Ec

c?C

7

/

VO4

"1

;7

/

:.2020

Basic Geotechnical Engineering

USN

15CV45

@M ,M1q2

tr, ,,BRARY

Time: 3 hrs. Max. Marks: 80

ti

U

U

Module-1

? I a. Define : Void ratio , Porosity , Degree of saturation and Air content.

b. Derive the expression for dry density of soil in the form

(1- n

u

)G.

Y

.

Yd

" with usual notations.

)

1 wG

ct ?

7=

c. Define Liquid limit , Relative consistency and Toughness index.

N

c -

P -

C

0

z

2 cs-

OR

2 a. State Stoke's law. List the assumptions (04 Marks)

b. Explain with the help of particle size distribution curves : Well graded soil , Poorly graded

soil and Gap graded soil. (06 Marks)

c. A fully saturated soil sample has a water content of 35% and specific gravity of 2.65.

Determine its porosity , saturated unit weight and dry unit weight. (06 Marks)

Module-2

3 a. What are the different types of clay minerals commonly found in soils? Explain any one

with their structure. (06 Marks)

b. The observations of a standard proctor test are as follows :

Note: Answer any FIVE full questions, choosing ONE full question from each module.

(04 Marks)

(06 Marks)

(06 Marks)

Dry density , KN/m

3

16.16 17.06 18.61 18.95 18.78 17.13

Water content , % 5 8.81 11.25 13.05 14.40 19.25

i) Plot the compaction curve and determine OMC and v

d ma -

ii) Also compute void ratio and degree of saturation at optimum condition. Take G = 2.77.

(10 Marks)

OR

4 a. Differentiate between Standard and Modified Proctor's tests. (04 Marks)

b. Discuss the effect of compaction on different properties of soil. (06 Marks)

c. Explain Electrical diffuse double layer and Adsorbed water. (06 Marks)

Module-3

5 a. Differentiate between : i) Seepage velocity and discharge velocity

ii) Coefficient of permeability and coefficient of percolation. (04 Marks)

b. Derive an expression for the determination of coefficient of permeability by falling head

0

z

permeameter. (06 Marks)

C

c. An earthen dam 300m long is built on an impervious foundation with a horizontal filter

0

under the d/s slope. The horizontal and vertical permeability's of the soil are 5 x 10

-5

m/sec

and 2 x in/sec respectively. The full reservoir level is 20m above the downstream filter.

The flow net consists of 4 flow channels and 16 equipotential drops. Estimate the seepage

loss in litres per day per unit length of the darn. (06 Marks)

15C

OR

6 a. What is a Flownet? Briefly explain the characteristics and uses of tlownets. (08 Marks)

b. A clay structure of thickness 8m is located at a depth of 6m below the ground surface, it is

overlayed by fine sand, the water table is located at a depth of 2m below ground surface. For

fine sand submerged unit weight is 10.2 kN/m

3

. The moist unit weight of sand located above

water table is 16kN/m

3

. For clay layer G = 2.76 and w = 25%. Compute the effective stress

at the middle of clay layer. (08 Marks)

Module-4

7 a. What are Curve fitting methods used in consolidation test? Explain anyone with a neat

sketch. (08 Marks)

b. A bed of compressible clay, 4m thick has pervious sand at top and an impervious rock at the

bottom. In a consolidation test on an undisturbed sample of clay from this deposit, 90%

settlement was reached in 4 hours. The sample was 20mm thick. Estimate the time in years

for the building founded over this deposit to reach 90% of its final settlement. (08 Marks)

OR

8 a. Differentiate compaction from consolidation.

b. Define the terms : Coefficient of compressibility

Compression index.

c. Explain the significance of preconsolidation pressure.

determining it.

(04 Marks)

, Coefficient of consolidation and

(06 Marks)

Describe Casagrande's method of

(06 Marks)

9 a.

b.

c.

Module-5

Explain Mohr ? Coulomb failure theory. (04 Marks)

Explain Sensitivity and Thixotropy of clay. (06 Marks)

A shear vane of 75mm diameter and 110mm length was used to measure the shear strength

of a soft clay. If a torque of 600 N-m was required to shear the soil, calculate the shear

strength. The vane was then rotated rapidly to cause remoulding of the soil. The torque

required in the remoulded state was 200 N-m. Determine the sensitivity of the soil.(06 Marks)

OR

10 a. What are the advantages and disadvantages of direct shear test over triaxial test? (08 Marks,:-

b. A direct shear test was carried out on a cohesive soil sample and the following results were

obtained :

Normal stress, kN/m

2

150 250

Shear stress at failure kN/m

2

110 120

What would be the deviator stress at failure, if a triaxial test is carried out on the same soil

with a cell pressure of 150kN/m

2

. (08 Marks)

*

2 of 2

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Fourth Semester B.E. Degree Examination,

\.r-

Ec

c?C

7

/

VO4

"1

;7

/

:.2020

Basic Geotechnical Engineering

USN

15CV45

@M ,M1q2

tr, ,,BRARY

Time: 3 hrs. Max. Marks: 80

ti

U

U

Module-1

? I a. Define : Void ratio , Porosity , Degree of saturation and Air content.

b. Derive the expression for dry density of soil in the form

(1- n

u

)G.

Y

.

Yd

" with usual notations.

)

1 wG

ct ?

7=

c. Define Liquid limit , Relative consistency and Toughness index.

N

c -

P -

C

0

z

2 cs-

OR

2 a. State Stoke's law. List the assumptions (04 Marks)

b. Explain with the help of particle size distribution curves : Well graded soil , Poorly graded

soil and Gap graded soil. (06 Marks)

c. A fully saturated soil sample has a water content of 35% and specific gravity of 2.65.

Determine its porosity , saturated unit weight and dry unit weight. (06 Marks)

Module-2

3 a. What are the different types of clay minerals commonly found in soils? Explain any one

with their structure. (06 Marks)

b. The observations of a standard proctor test are as follows :

Note: Answer any FIVE full questions, choosing ONE full question from each module.

(04 Marks)

(06 Marks)

(06 Marks)

Dry density , KN/m

3

16.16 17.06 18.61 18.95 18.78 17.13

Water content , % 5 8.81 11.25 13.05 14.40 19.25

i) Plot the compaction curve and determine OMC and v

d ma -

ii) Also compute void ratio and degree of saturation at optimum condition. Take G = 2.77.

(10 Marks)

OR

4 a. Differentiate between Standard and Modified Proctor's tests. (04 Marks)

b. Discuss the effect of compaction on different properties of soil. (06 Marks)

c. Explain Electrical diffuse double layer and Adsorbed water. (06 Marks)

Module-3

5 a. Differentiate between : i) Seepage velocity and discharge velocity

ii) Coefficient of permeability and coefficient of percolation. (04 Marks)

b. Derive an expression for the determination of coefficient of permeability by falling head

0

z

permeameter. (06 Marks)

C

c. An earthen dam 300m long is built on an impervious foundation with a horizontal filter

0

under the d/s slope. The horizontal and vertical permeability's of the soil are 5 x 10

-5

m/sec

and 2 x in/sec respectively. The full reservoir level is 20m above the downstream filter.

The flow net consists of 4 flow channels and 16 equipotential drops. Estimate the seepage

loss in litres per day per unit length of the darn. (06 Marks)

15C

OR

6 a. What is a Flownet? Briefly explain the characteristics and uses of tlownets. (08 Marks)

b. A clay structure of thickness 8m is located at a depth of 6m below the ground surface, it is

overlayed by fine sand, the water table is located at a depth of 2m below ground surface. For

fine sand submerged unit weight is 10.2 kN/m

3

. The moist unit weight of sand located above

water table is 16kN/m

3

. For clay layer G = 2.76 and w = 25%. Compute the effective stress

at the middle of clay layer. (08 Marks)

Module-4

7 a. What are Curve fitting methods used in consolidation test? Explain anyone with a neat

sketch. (08 Marks)

b. A bed of compressible clay, 4m thick has pervious sand at top and an impervious rock at the

bottom. In a consolidation test on an undisturbed sample of clay from this deposit, 90%

settlement was reached in 4 hours. The sample was 20mm thick. Estimate the time in years

for the building founded over this deposit to reach 90% of its final settlement. (08 Marks)

OR

8 a. Differentiate compaction from consolidation.

b. Define the terms : Coefficient of compressibility

Compression index.

c. Explain the significance of preconsolidation pressure.

determining it.

(04 Marks)

, Coefficient of consolidation and

(06 Marks)

Describe Casagrande's method of

(06 Marks)

9 a.

b.

c.

Module-5

Explain Mohr ? Coulomb failure theory. (04 Marks)

Explain Sensitivity and Thixotropy of clay. (06 Marks)

A shear vane of 75mm diameter and 110mm length was used to measure the shear strength

of a soft clay. If a torque of 600 N-m was required to shear the soil, calculate the shear

strength. The vane was then rotated rapidly to cause remoulding of the soil. The torque

required in the remoulded state was 200 N-m. Determine the sensitivity of the soil.(06 Marks)

OR

10 a. What are the advantages and disadvantages of direct shear test over triaxial test? (08 Marks,:-

b. A direct shear test was carried out on a cohesive soil sample and the following results were

obtained :

Normal stress, kN/m

2

150 250

Shear stress at failure kN/m

2

110 120

What would be the deviator stress at failure, if a triaxial test is carried out on the same soil

with a cell pressure of 150kN/m

2

. (08 Marks)

*

2 of 2

15C

OR

6 a. What is a Flownet? Briefly explain the characteristics and uses of flownets. (08 Marks)

b. A clay structure of thickness 8m is located at a depth of 6m below the ground surface, it is

overlayed by fine sand, the water table is located at a depth of 2m below ground surface. For

fine sand submerged unit weight is 10.2 kN/m

3

. The moist unit weight of sand located above

water table is 16kN/m

3

. For clay layer G = 2.76 and w = 25%. Compute the effective stress

at the middle of clay layer. (08 Marks)

Module-4

7 a. What are Curve fitting methods used in consolidation test? Explain anyone with a neat

sketch. (08 Marks)

b. A bed of compressible clay, 4m thick has pervious sand at top and an impervious rock at the

bottom. In a consolidation test on an undisturbed sample of clay from this deposit, 90%

settlement was reached in 4 hours. The sample was 20mm thick. Estimate the time in years

for the building founded over this deposit to reach 90% of its final settlement. (08 Marks)

OR

8 a. Differentiate compaction from consolidation.

b. Define the terms : Coefficient of compressibility

Compression index.

c. Explain the significance of preconsolidation pressure.

determining it.

(04 Marks)

, Coefficient of consolidation and

(06 Marks)

Describe Casagrande's method of

(06 Marks)

9 a.

b.

c.

Module-5

Explain Mohr ? Coulomb failure theory. (04 Marks)

Explain Sensitivity and Thixotropy of clay. (06 Marks)

A shear vane of 75mm diameter and 110mm length was used to measure the shear strength

of a soft clay. If a torque of 600 N-m was required to shear the soil, calculate the shear

strength. The vane was then rotated rapidly to cause remoulding of the soil. The torque

required in the remoulded state was 200 N-m. Determine the sensitivity of the soil.(06 Marks)

OR

10 a. What are the advantages and disadvantages of direct shear test over triaxial test? (08 Marks,.?

b. A direct shear test was carried out on a cohesive soil sample and the following results were

obtained :

Normal stress, kN/m

2

150 250

Shear stress at failure kN/m

2

110 120

What would be the deviator stress at failure, if a triaxial test is carried out on the same soil

with a cell pressure of I 50kN/m

2

. (08 Marks)

* Y * *

2 of 2

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This post was last modified on 28 February 2020