JNTU Kakinada B-Tech 3-1 RT31011 I GEOTECHNICAL ENGINEERING – I (Civil Engineering) R13 April 2018 Question Paper

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Code No: RT31011
III B. Tech I Semester Supplementary Examinations, May -2018
GEOTECHNICAL ENGINEERING ? I (Civil Engineering)Time: 3 hours Max. Marks: 70
Note: 1. Question Paper consists of two parts (Part-A and Part-B) 2. Answering the question in Part-A is compulsory
3. Answer any THREE Questions from Part-B
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PART ?A
1 a) Define texture of a soil. [3M]
b) Write the equation of the A-line, and explain the terms in it. [4M]
c) What is an equipotential line and a flow line? [4M]
d) A point load of 100 kN is applied at the ground surface. What is the value of vertical
stress at a depth of 3 m and 2 m radially from the point of application?
[4M]
e) Write the relationship between coefficient of permeability, coefficient of
consolidation and unit weight of water.
[3M]
f) Define critical void ratio. [4M]
PART ?B
2 a) Derive the relationship between bulk density, degree of saturation and void ratio of a
soil.
[8M]
b) A dry soil has a void ratio of 0.65 and its grain specific gravity is = 2.80. What
is its unit weight? Water is added to the sample so that its degree of saturation is 60%
without any change in void ratio. Determine the water content and unit weight. The
sample is next placed below water. Determine the true unit weight (not considering
buoyancy) if the degree of saturation is 95% and 100% respectively.
[8M]
3 a) Explain the procedure to conduct the hydrometer test on a soil sample in the lab. [8M]
b) Dry soil with G= 2.71 is mixed with 16% by weight of water and compacted to
produce a cylindrical sample of 38 mm diameter and 76mm long with 6% air content.
Calculate the mass of the mixed soil that will be required and the void ratio of the
sample.
[8M]
4 a) Derive the expression to determine the capillary rise in a soil deposit. [8M]
b) A uniform soil deposit has a void ratio 0.60 and specific gravity of 2.65. The natural
ground water is at 2.50 m below natural ground level. Due to capillary moisture, the
average degree of saturation above ground water table is 50%. Determine the neutral
pressure, total pressure and effective pressure at a depth of 6.0 m. Draw a neat sketch.
[8M]
5 a) Compare and contrast Boussinesq?s and Westergaard?s theories? [8M]
b) A strip load of considerable length and 1.50 m width transmits a pressure of 150
kN/m
2
to the underlying soil. Determine the maximum principal stress at 0.75 m
depth below the footing, if the point lies (i) directly below the centre of the footing,
and (ii) directly below the edge of the footing.
1 of 2

[8M]
R13
SET – 1
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Code No: RT31011
III B. Tech I Semester Supplementary Examinations, May -2018
GEOTECHNICAL ENGINEERING ? I (Civil Engineering)Time: 3 hours Max. Marks: 70
Note: 1. Question Paper consists of two parts (Part-A and Part-B) 2. Answering the question in Part-A is compulsory
3. Answer any THREE Questions from Part-B
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PART ?A
1 a) Define texture of a soil. [3M]
b) Write the equation of the A-line, and explain the terms in it. [4M]
c) What is an equipotential line and a flow line? [4M]
d) A point load of 100 kN is applied at the ground surface. What is the value of vertical
stress at a depth of 3 m and 2 m radially from the point of application?
[4M]
e) Write the relationship between coefficient of permeability, coefficient of
consolidation and unit weight of water.
[3M]
f) Define critical void ratio. [4M]
PART ?B
2 a) Derive the relationship between bulk density, degree of saturation and void ratio of a
soil.
[8M]
b) A dry soil has a void ratio of 0.65 and its grain specific gravity is = 2.80. What
is its unit weight? Water is added to the sample so that its degree of saturation is 60%
without any change in void ratio. Determine the water content and unit weight. The
sample is next placed below water. Determine the true unit weight (not considering
buoyancy) if the degree of saturation is 95% and 100% respectively.
[8M]
3 a) Explain the procedure to conduct the hydrometer test on a soil sample in the lab. [8M]
b) Dry soil with G= 2.71 is mixed with 16% by weight of water and compacted to
produce a cylindrical sample of 38 mm diameter and 76mm long with 6% air content.
Calculate the mass of the mixed soil that will be required and the void ratio of the
sample.
[8M]
4 a) Derive the expression to determine the capillary rise in a soil deposit. [8M]
b) A uniform soil deposit has a void ratio 0.60 and specific gravity of 2.65. The natural
ground water is at 2.50 m below natural ground level. Due to capillary moisture, the
average degree of saturation above ground water table is 50%. Determine the neutral
pressure, total pressure and effective pressure at a depth of 6.0 m. Draw a neat sketch.
[8M]
5 a) Compare and contrast Boussinesq?s and Westergaard?s theories? [8M]
b) A strip load of considerable length and 1.50 m width transmits a pressure of 150
kN/m
2
to the underlying soil. Determine the maximum principal stress at 0.75 m
depth below the footing, if the point lies (i) directly below the centre of the footing,
and (ii) directly below the edge of the footing.
1 of 2

[8M]
R13
SET – 1
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Code No: RT31011

6 a) Explain the Spring Analogy concept of consolidation, with neat sketches? [8M]
b) The void ratio of clay A decreased from 0.572 to 0.505 under a change in pressure
from 1.20 kPa to 1.80 kPa. The void ratio of clay B decreased from 0.612 to 0.597
under the same increment of pressure. The thickness of sample A was 1.50 times that
of B. Nevertheless the time required for 50% consolidation was three times longer for
sample B than for sample A. What is the ratio of the coefficient of permeability of A
to that of B?
[8M]
7 a) Explain the three standard triaxial shear tests with respect to drainage conditions? [8M]
b) The following data relate to a triaxial compression tests performed on a soil sample:
Test No. Chamber pressure (kPa)Maximum
deviator stress (kPa)Pore pressure at
maximum deviator
stress (kPa)1. 80 175 45
2. 150 240 50
3. 210 300 60
Determine the effective shear strength parameters of the soil, graphically only.
[8M]

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2 of 2

R13
SET – 1