1. For purely cohesive soil, the bearing capacity is given by which of the following equation?
a) qf = 5.7 c + σ̅
b) qf = c + σ̅
c) qf = 5.7 c
d) All of the mentioned
Explanation: For purely cohesive soil the bearing capacity is
qf = c Nc + σ̅ Nq = 5.7 c + σ̅
Where σ̅ = γ D if the water table is below the base of the footing.
2. The parameters Nc, Nq, Nγ in the equations of bearing capacity failure are known as _________
a) Constant head
b) Bearing capacity factors
c) Effective pressure
d) Load intensity
Explanation: The parameters Nc, Nq, Nγ are the dimensionless numbers, known as bearing capacity factors depending only on the angle of shearing resistance of the soil.
3. For purely cohesive soil, local shear failure may be assumed to occur when the soil is ___________
a) Medium to soft
b) Soft to medium
c) Hard
d) All of the mentioned
Explanation: For purely cohesive soil, local shear failure may be assumed to occur when the soil is soft to medium, with an unconfined compressive strength qu ≤ 100 kN/m2.
4. Which of the following is a limitation, of assumption in Terzaghi’s analysis?
a) φ changes when the soil is compressed and strip footing has a rough base
b) Soil is homogeneous
c) None of the mentioned
d) All of the mentioned
Explanation: As the soil compress, φ changes; slight downward movement of footing may not develop fully the plastic planes.
5. Which of the following are original Terzaghi values for Nγ?
a) 34° and 48°
b) 60°
c) None of the mentioned
d) All of the mentioned
Explanation: The values of Nγ for φ of 34° and 48° are the original Terzaghi values which were used by Bowles to back compute Kpγ.
6. According to the assumptions in Terzaghi’s analysis, the soil is _______________
a) Homogeneous and Isotropic
b) Non Homogeneous
c) None of the mentioned
d) All of the mentioned
Explanation: In Terzaghi’s analysis the soil is homogeneous and isotropic and its shear strength is represented by Coulomb’s equation.
7. The Terzaghi’s general bearing capacity equation is represented as ___________
a) qf = 5.7 c + σ̅
b) qf = c Nc + σ̅. Nq + 0.5γBNγ
c) qf = c Nc + σ̅. Nq
d) qf = c Nc
Explanation: “qf = c Nc + σ̅. Nq + 0.5γBNγ” is known as Terzaghi’s general bearing capacity equation for a continuous footing.
8. Local shear failure generally occurs in ___________
a) Dense sand
b) Non-cohesive soil
c) Loose sand
d) All of the mentioned
Explanation: Local shear failure generally occurs in loose sand while general shear failure occurs in dense sand.
9. The curve for Nq and Nγ for the transition state from φ = 28° and φ = 38° was given by __________
a) Peck
b) Hanson
c) Thorn burn
d) All of the mentioned
Explanation: Peck, Hansen, and Thorn burn gave curves for Nq and Nγ for the transition state from φ = 28° and φ = 38°, in which they assumed general shear failure when φ > 28°.
10. terzaghi’s bearing capacity equation is not applicable for ____________
a) Depth effect and Inclination factor
b) Narrow slope
c) None of the mentioned
d) All of the mentioned
Explanation: Terzaghi assumed the value of angle ψ = φ, which is not true. Since footings are normally rough, ψ has been found close to 45° + φ/2 than to φ, thus Terzaghi’s bearing capacity equations do not have provision for including depth effects, inclination factors, etc.