Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2018 Winter 5th Sem New 2152204 Rock Mechanics Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE - SEMESTER ?V (NEW) EXAMINATION ? WINTER 2018
Subject Code:2152204 Date:16/11/2018
Subject Name:Rock Mechanics
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.
MARKS
Q.1 (a)
What do you understand by engineering rock mechanics & its application in mining?
03
(b)
With the help of neat diagram, explain stress-strain curve.
04
(c)
Describe briefly about the different tests to determine the Permeability of rock sample.
07
Q.2 (a)
Write the name of different physical properties of rock. Why knowledge of these properties
is important for a mining engineer?
03
(b)
A rock sample has bulk density of 2.85 gm/cc. Its moisture content was found to be 1.40
%. Find out its dry density.
04
(c)
Briefly explain ?Compressive strength of rock?.
07
OR
(c)
What are the methods of determining of shear strength of rock? Describe about any one
method in detail.
07
Q.3 (a)
What is meant by hardness of rocks? Also write the mohr?s scale of hardness.
03
(b)
A rock specimen had moisture content of 2.25 %.Volume of solids was found to be 85 %
find out the degree of saturation of rock sample.
04
(c)
Discuss the factors influencing velocity of waves through a rock mass?
07
OR
Q.3 (a)
What do you mean by durability of rock or rockmass?
03
(b)
Explain Porosity, density and moisture content of rock.
04
(c)
Explain briefly about rheology & rheological models.
07
Q.4 (a)
Discuss about the effect of joints and fracture on mechanical properties of rocks.
03
(b)
Briefly describe about the creep behaviour of rock.
04
(c)
Discuss the Griffith?s theory of fracture in rock mass.
07
OR
Q.4 (a)
Define Modulus of elasticity and Poisson?s ratio.
03
(b)
A sample of diameter 50 mm and thickness 25 mm was tested by Brazilian test. If failure
occurs at a load of 1964.28 kg, determine the tensile strength in kg/cm
2
.
04
(c)
What do you understand by pre-mining state of stress? Explain hydraulic fracturing method
in detail.
07
Q.5 (a)
Discuss the necessity and requirements of ?in-situ? tests.
03
(b)
Define failure in rocks. Explain different types of failure in rock.
04
(c)
Two rock samples of 50 mm diameter were subjected to point load test. The rupture was
observed at a load of 500 kg and 600 kg respectively. Find out the point load strength in
kg/cm
2
.of both sample and calculate the unconfined compressive strength of each sample.
07
OR
Q.5 (a)
Discuss Idealy Plastic, perfectly Plastic and Elastic Plastic materials.
03
(b)
Discuss Mohr?s and Coulomb theory of rock failure.
04
(c)
What are the different physical properties of soil? Explain briefly.
07
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This post was last modified on 20 February 2020