Engineering Questions with Answers - Multiple Choice Questions
Mohr – Coulomb Failure Theory
1 - Question
The curve obtained by plotting the normal and shear stress is called as ___________
a) Mohr’s envelope
b) Coulomb envelope
c) Strength envelope
d) Stress envelope
View Answer
Answer: c
Explanation: If the normal and shear stress corresponding to failure are plotted, then a curve is obtained. The plot or curve is called the strength envelope.
2 - Question
Which of the following is coulomb’s strength equation?
a) S = c + tan φ
b) C = s + c tan φ
c) S = c + σ tan φ
d) S = tan φ
View Answer
Answer: c
Explanation: Coulomb defined the function F (σ) as a linear function of σ and gave the following strength equation:
S = c + σ tan φ.
3 - Question
The critical shear stress causing failure of material depends upon ____________
a) Properties of the material and normal stress on the plane
b) Intermediate principal stress
c) None of the mentioned
d) All of the mentioned
View Answer
Answer: a
Explanation: According to Mohr’s strength theory, the critical shear stress causing failure depends upon the properties of the materials as well as on normal stress on the failure plane.
4 - Question
Theory of failure, was first proposed by ____________
a) Coulomb
b) Mohr
c) Casagrande
d) Darcy
View Answer
Answer: a
Explanation: The theory of failures was first expressed by coulomb in 1776 and later generalized by Mohr.
5 - Question
The Mohr-Coulomb theory can be expressed algebraically by, which of the following equation.
a) S = c + σ tan φ
b) τf = s = F(σ)
c) s = F(σ)
d) τf = F(σ)
View Answer
Answer: b
Explanation: The Mohr-Coulomb failure theory can be expressed algebraically by the equation:τf = s = F (σ)
Where, τf = s=shear stress on failure plane, at failure=shear resistance of material
F (σ) = function of normal stress.
6 - Question
According to Coulomb, the relationship between shear strength and normal stress could be represented by _________
a) Linear curve
b) Parabolic curve
c) Straight line
d) None of the mentioned
View Answer
Answer: b
Explanation: Coulomb considered that the relationship between shear strength and normal stress could be adequately represented by the straight line.
7 - Question
Mohr envelope can be considered to be straight if the angle of internal friction φ is assumed to be __________
a) 90°
b) >90°
c) <90°
d) None of the mentioned
View Answer
Answer: d
Explanation: Mohr envelope can be considered straight if the angle of internal friction φ is assumed to be a constant.
8 - Question
Which of the following stresses does not have any influence on strength of a material?
a) Major principal stress
b) Minor principal stress
c) Intermediate principal stress
d) Shearing stress
View Answer
Answer: c
Explanation: When a material is subjected to three dimensional stresses, the intermediate principal stress does not have any influence on the strength of material.
9 - Question
The parameter φ in coulomb’s equation “S = c + σ tan φ”, represents ___________
a) Shearing resistance and Angle of internal friction
b) Angle of slope
c) None of the mentioned
d) All of the mentioned
View Answer
Answer: a
Explanation: The empirical constant φ in coulomb’s equation represents angle of internal friction or shearing resistance respectively.