Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2018 Winter 5th Sem Old 150604 Geotechnical Engineering I Previous Question Paper
1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (OLD) EXAMINATION ? WINTER 2018
Subject Code:150604 Date: 11/12/2018
Subject Name: Geotechnical Engineering - I
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Define the following terms 03
1. Void ratio 2. Degree of saturation 3. Air content
(b) Derive relation between void ratio, degree of saturation, specific gravity and
water content
04
(c ) A soil sample has porosity of 40 %. The specific gravity of solids is 2.70.
Calculate (1) Void ratio (2) Dry Density (3) Unit weight if the soil is 50%
saturated (4) unit weight if the soil is completely saturated.
07
Q.2 (a) Explain Atterberg limits of Soil 07
(b) Explain I. S. Classification of Coarse Grain Soil 07
OR
(b) Explain Aquifer, Aquiclude and Aquifuge 07
Q.3 (a) Explain falling head method for finding permeability of soil in laboratory 07
(b) Calculate the co-efficient of permeability of a soil sample, 6 cm in height and 50
cm
2
in cross-sectional area, if a quantity of water 430 ml passed down in 10
minutes, under effective head of 40 cm. On oven drying the test specimen has
mass of 498 gm. Taking the specific gravity 2.7, calculate the seepage velocity.
07
OR
Q.3 (a) List the factors affecting compaction of soil and explain any one in detail. 07
(b) A laboratory compaction test on soil having the specific gravity 2.68 gave
maximum dry density 1.82 g/cm
3
at water content 17%. Determine degree of
saturation, air content, and percentage air voids at maximum dry density. What
would be theoretical maximum dry density corresponding to zero air voids at
optimum water content.
07
Q.4 (a) Explain Traiaxial test with sketch and different drainage conditions 07
(b) A cylinder of soil fails under an axial vertical stress of 160 kN/m
2
, when it is
laterally unconfined. The failure plane makes an angle of 50? with the horizontal.
Calculate the value of cohesion and the angle of internal friction of the soil
07
OR
Q.4 (a) Explain Mohor- Coulomb failure theory 07
(b) A vane 10 cm long and 8 cm in diameter, was pressed into soft clay at bottom of
a bore hole. Torque was applied and gradually increased to 45 N-m when failure
took place. Subsequently, the the vane rotated rapidly so as to completely
remolded the soil. The remolded soil was sheared at a torque of 18 N-m.
Calculate the cohesion of the clay in natural and remolded states and also the
value of sensitivity.
07
Q.5 (a) Explain piston and spring analogy method for the mechanics of consolidation 07
www.FirstRanker.com www.FirstRanker.com
www.FirstRanker.com
FirstRanker.com - FirstRanker's Choice
www.FirstRanker.com
1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (OLD) EXAMINATION ? WINTER 2018
Subject Code:150604 Date: 11/12/2018
Subject Name: Geotechnical Engineering - I
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Define the following terms 03
1. Void ratio 2. Degree of saturation 3. Air content
(b) Derive relation between void ratio, degree of saturation, specific gravity and
water content
04
(c ) A soil sample has porosity of 40 %. The specific gravity of solids is 2.70.
Calculate (1) Void ratio (2) Dry Density (3) Unit weight if the soil is 50%
saturated (4) unit weight if the soil is completely saturated.
07
Q.2 (a) Explain Atterberg limits of Soil 07
(b) Explain I. S. Classification of Coarse Grain Soil 07
OR
(b) Explain Aquifer, Aquiclude and Aquifuge 07
Q.3 (a) Explain falling head method for finding permeability of soil in laboratory 07
(b) Calculate the co-efficient of permeability of a soil sample, 6 cm in height and 50
cm
2
in cross-sectional area, if a quantity of water 430 ml passed down in 10
minutes, under effective head of 40 cm. On oven drying the test specimen has
mass of 498 gm. Taking the specific gravity 2.7, calculate the seepage velocity.
07
OR
Q.3 (a) List the factors affecting compaction of soil and explain any one in detail. 07
(b) A laboratory compaction test on soil having the specific gravity 2.68 gave
maximum dry density 1.82 g/cm
3
at water content 17%. Determine degree of
saturation, air content, and percentage air voids at maximum dry density. What
would be theoretical maximum dry density corresponding to zero air voids at
optimum water content.
07
Q.4 (a) Explain Traiaxial test with sketch and different drainage conditions 07
(b) A cylinder of soil fails under an axial vertical stress of 160 kN/m
2
, when it is
laterally unconfined. The failure plane makes an angle of 50? with the horizontal.
Calculate the value of cohesion and the angle of internal friction of the soil
07
OR
Q.4 (a) Explain Mohor- Coulomb failure theory 07
(b) A vane 10 cm long and 8 cm in diameter, was pressed into soft clay at bottom of
a bore hole. Torque was applied and gradually increased to 45 N-m when failure
took place. Subsequently, the the vane rotated rapidly so as to completely
remolded the soil. The remolded soil was sheared at a torque of 18 N-m.
Calculate the cohesion of the clay in natural and remolded states and also the
value of sensitivity.
07
Q.5 (a) Explain piston and spring analogy method for the mechanics of consolidation 07
www.FirstRanker.com www.FirstRanker.com
www.FirstRanker.com
www.FirstRanker.com
2
(b) An undisturbed sample of clay 24 mm thick consolidated 50% in 20 minutes,
when tested in laboratory with drainage allowed at top and bottom. The caly layer
from which sample is obtained is 4 m thick in the field. How much time it would
take to consolidate 50% with double drainage? If clay stratum has only single
drainage calculates the time to consolidate 50%. Assume uniform distribution of
consolidation pressure.
07
OR
Q.5 (a) Differentiate between Compaction and Consolidation 07
(b) A clay layer has a thickness of 5 m and is subjected to a pressure of 60 kN/m
2
. If
the layer has double drainage and undergoes 50 % consolidation in one year,
determine the coefficient of consolidation taking Tv = 0.197. Also if the
coefficient of permeability is 0.025 m /year, determine the settlement in one year
and rate of flow of water per unit area in one year.
07
*************
www.FirstRanker.com www.FirstRanker.com
www.FirstRanker.com
FirstRanker.com - FirstRanker's Choice
This post was last modified on 20 February 2020