# Foundation Engineering Questions and Answers – Reinforced Earth

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This set of Foundation Engineering online test focuses on “Reinforced Earth”.

1. The essential feature of reinforced earth is that __________ develops between compacted layer of earth and reinforcing elements.
a) friction
b) tension
c) compression
d) shear

Explanation: The reinforced earth consists of a compacted soil mass within which reinforcing elements are embedded. The essential feature of the reinforced earth is that friction develops between compacted layer of earth and reinforcing elements.

2. ______ is developed in reinforcement.
a) Friction
b) Tension
c) Compression
d) Shear

Explanation: The essential feature of reinforced earth is that friction develops between compacted layer of earth and reinforcing elements. The soil transfers the forces built up in the earth mass to the reinforcement by means of friction. Thus, tension is developed in the reinforcement.

3. The modern form of application of reinforced earth was first developed by _____
a) Darcy
b) Skempton
c) Henry Vidal
d) Marshal

Explanation: The modern form of application of reinforced earth was first developed by Henry Vidal who first constructed major retaining walls in France in 1968. Darcy has contributions in the field of soil permeability.

4. The reinforcement members are used to provide _______ in earth mass where _____ are produced.
a) tensile strength, compressive stresses
b) tensile strength, shear stresses
c) compressive strength, tensile stresses
d) shear strength, tensile stresses

Explanation: The reinforcement members are used to provide tensile strength in earth mass where shear stresses are produced. The provision of the members leads to the redistribution of the stresses internally within each member.

5. In reinforcing elements, galvanised steel strips of _________ width and ____ thickness are used commonly.
a) 50 to 100 mm, 9mm
b) 50 to 70 mm, 20mm
c) 110 to 180 mm, 30mm
d) 200 to 310 mm, 40mm

Explanation: In reinforcing elements, galvanised steel strips of 50 to 100 mm width and 9 mm thickness are used commonly. These galvanised steel strips are several meters in length.

6. In general from the data on galvanised steel, it has a service life of _____ in soil.
a) 2 days
b) 120 months
c) 10 years
d) 120 years

Explanation: Since the galvanised steel is resistant to corrosion, from the data available on the rate of corrosion of galvanised steel it indicates that, elements if this material are to have a service life of 120 years in soil.

7. The soil used in the backfill should have particles of not more than _____ passing 63 μm sieve.
a) 10%
b) 20%
c) 30%
d) 40%

Explanation: The soil used in the backfill should predominantly be coarse-grained and it is proposed that not more than 10% of the particles should pass 63 μm sieve. The first level of the reinforced strips is placed at the ground level.

8. The wall facing element is also known as _______
a) plaster
b) POP
c) skin
d) coat

Explanation: The wall facing element is provided at the free boundary of a reinforced earth structure. This is done to provide some form of barrier and these elements are known as skin. These elements can be flexible or stiff.

9. In general, the reinforced earth structures are ________
a) flexible
b) stiff
c) rigid
d) firm

Explanation: In general, the reinforced earth structures are quite flexible. Being flexible, they can withstand foundation deformations or the foundation settlements. They can also withstand earthquake force more efficiently.

10. The reinforced earth structures can be transported easily.
a) True
b) False

Explanation: The most of the reinforced earth structures are quite flexible. Being flexible, they can be much easily transported. Since they can be transported easily, these can be constructed speedily.

11. In design of reinforced earth wall, the Rankine’s earth pressure is valid.
a) True
b) False

Explanation: In design of reinforced earth wall, the Rankine’s earth pressure is valid. Rankine’s earth pressure for active state holds good due to which the failure plane makes an angle $$45°+\frac{φ}{2}.$$

12. By the use of reinforcing elements in earth __________
a) it restrains lateral deformation
b) it provides lateral deformation
c) it produces shear stress
d) it produces shear failure

Explanation: The reinforced soil concept is based in the mobilization of inter facial shearing resistance between the soil and the reinforcement which in turn restrains the lateral deformation of the soil.

Sanfoundry Global Education & Learning Series – Foundation Engineering.

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