1. The net safe bearing capacity is defined by which of the following equation?
a) qns=qnf / F
b) qns = qnf + σ̅
c) qns = qf – σ̅
d) All of the mentioned
Explanation: The net safe bearing capacity is the net ultimate bearing capacity divided by a factor of safety F i.e., qns = qnf/F.
2. The safe bearing capacity can also be referred as _________
a) Net safe bearing capacity
b) Ultimate bearing capacity
c) Safe bearing pressure
d) Net soil pressure
Explanation: Sometimes, the safe bearing capacity is also referred to as the ultimate bearing capacity qf divided by a factor of safety F.
3. Rankine considered the first soil element (element 1) at ___________
a) Base of the structure
b) Below the foundation
c) Edge of the footing
d) All of the mentioned
Explanation: Rankine considered the equilibrium of two soil elements, The first one immediately below the foundation (element 1).
4. The bearing capacity of cohesion-less soil at the ground surface is __________
a) Unity
b) Less than one
c) Zero
d) Greater than one
Explanation: According to Rankine’s equation bearing capacity of cohesion less soil is zero at the ground surface.
5. When a state of equilibrium is reached under the footing?
a) Load on footing increase
b) Load on footing decreases
c) Safe bearing capacity of the soil is reached
d) None of the mentioned
Explanation: When the load on footing increases, and approaches a value qf, a state of plastic equilibrium is reached under the footing
6. Rankine considered the equilibrium of second soil element at __________
a) Base of the structure
b) Below the foundation
c) Edge of the footing
d) Top of the foundation
Explanation: Rankine considered the equilibrium of the other soil element (element 2) beyond the edge of the footing, but adjacent to element 1.
7. During the state of shear failure, which of the following principal stress relationship exist?
a) σ1 = σ tan α + 2c tan α
b) σ1 = σ3 tan2 α + 2c tan α
c) σ1 = 2c tan α
d) σ1 = σ3 tan α
Explanation: During the state of shear failure (plastic equilibrium), the following principal stress relationship exists σ1 = σ3 tan2 α + 2c tan α
for cohesion-less soil,σ1 = σ3 tan2 α.
8. The symbol σ̅, represent which of the following term?
a) Ultimate bearing capacity
b) Effective surcharge
c) Gross pressure intensity
d) Bearing capacity
Explanation: σ̅ represents the effective surcharge at the base level of the foundation, assuming total unit weight for the portion of the soil above the water table and submerged unit weight for the portion below the water table
9. When a footing fails due to insufficient bearing capacity, distinct failure patterns are developed depending upon _________
a) Failure mechanism
b) Plastic equilibrium
c) Shear strength
d) All of the mentioned
Explanation: Experimental investigations have indicated that when a footing fails due to insufficient bearing capacity, distinct failure patterns are developed, depending upon the type of failure mechanism.
10. Vesic observed _____________ types of bearing capacity failures.
a) 2
b) 4
c) 3
d) 5
Explanation: In 1963, Vesic observed three types of bearing capacity failures:
i) General shear failure
ii) Local shear failure
iii) Punching shear failure.