Geotechnical Engineering Questions and Answers – Protective Filters

Geotechnical Engineering Objective Questions

Civil Engineering MCQs

This set of Geotechnical Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Protective Filters”.

1. A protective filter can also be called as __________

A) Reverse filter and Inverted filter
B) Horizontal filter
C) None of the mentioned
D) All of the mentioned

Answer is A)
Explanation: In protective filter, each subsequent layer becomes increasingly coarser than the previous one, and hence, it is also called a reverse filter or inverted filter.

2. The soil to be protected by protective filter is known as __________

A) Pervious materials
B) Protective materials
C) Base material
D) Porous materials

Answer is C)
Explanation: The soil to be protected i.e., the embankment or foundation material surrounding the filter is known as the base materials.

3. The requirements to be satisfied by a filter material were devised by which of the following organization?

A) U.S.B.R. Earth manual
B) Indian standard classification
C) PRA system
D) M.I.T system

Answer is A)
Explanation: United States Bureau of Reclamation set four main requirements to be satisfied by a filter material for it to be considered as a protective filter.

4. A protective filter is designed to provide _____________

A) Soil erosion
B) Quick drainage
C) Water moisture
D) All of the mentioned

Answer is B)
Explanation: A protective filter designed in such a manner as to provide quick drainage, yet prevent the movement of soil particles.

5. What type of filter is provided at the bottom of drainage sumps and trenches?

A) Drainage filter
B) Reverse filter
C) Weighting filter
D) Horizontal filter

Answer is C)
Explanation: Weighting filters at the bottom of drainage sumps and trenches arrest the percolating water at the exit and allow its safe exit without inducing piping.

6. The phreatic line of an earth dam can be kept within the body of the dam by ___________

A) Proper drainage filter
B) Providing protective filter
C) Increasing soil porosity
D) Increasing surface area

Answer is B)
Explanation: With a proper drainage filter under slope or rock fill toe, the phreatic line in an earth dam can be kept well within the body of the dam.

7. According to Terzaghi, the D15 size material must be more than the size of __________

A) D40
B) D85
C) D20
D) D10

Answer is B)
Explanation: The D15 size of filter material must not be more than 4 to 5 times D85 size of the base materials. This prevents the foundation materials from passing through the pores of the filter material.

8. The grain size curve of the filter should be parallel to that of ____________

A) Base materials
B) Filter
C) Seepage discharge
D) All of the mentioned

Answer is A)
Explanation: As per the criteria given by Terzaghi, the grain size curve of the material should be roughly parallel to that of the base materials.

9. The filter material should be ___________ enough to prevent buildup of seepage forces within the filter.

A) Coarse and Pervious
B) Finer
C) None of the mentioned
D) All of the mentioned

Answer is A)
Explanation: The filter material should be sufficiently coarse and pervious so that the incoming force is rapidly removed without any appreciable buildup of seepage forces within the filter.

10. A protective filter consists of layers of _____________

A) Base material
B) Pervious material
C) Filter material
D) Sheet-pile

... Answer is B)
Explanation: A protective filter consists of a combination of layers of pervious materials to provide quick drainage.