Engineering Geology Questions and Answers Part-12

1. Pick the wrong statement. The converging plates maybe ___________
a) Two continental plates
b) A continental plate and an oceanic plate
c) A continental plate and an island plate
d) Two oceanic plates

Answer: d
Explanation: The converging plates may be two continental plates, a continental plate and an oceanic plate or a continental plate and an island plate but not two oceanic plate.

2. The displacement at the hinge point is maximum.
a) True
b) False

Answer: b
Explanation: Greater the distance from the hinge points, larger is the displacement, so much that it may be negligible at the hinge point. Hence the statement above is not true.

3. Which rock is lifted up during the folding due to intrusions?
a) Overlying metamorphic rocks
b) Overlying igneous rocks
c) Overlying sedimentary rocks
d) Overlying petroleum rocks

Answer: c
Explanation: In magmatic intrusions, highly viscous magma may be forced up gradually and with considerable force so that sedimentary host rocks overlying are lifted up to provide the space for the rising magma.

4. The process of folding which is considered to be non-tectonic is ___________
a) Differential compression
b) Tangential compression
c) Intrusions
d) Tangential tension

Answer: a
Explanation: Folding due to differential compression is totally dependent on the load from above and are attributed to superficial causes. These are, therefore, non-tectonic folds.

5. What is the indirect cause for warping or folding?
a) Homogenous strata
b) Non-homogenous strata
c) Inclined strata
d) Curved strata

Answer: b
Explanation: If the strata in question is not homogenous, the bending may not be uniform in character and results in warping or folding of different types

6. What is the reason for rock bursts?
a) Change in attitude of rocks
b) Shattering of rocks
c) Intense precipitation
d) Strained nature

Answer: d
Explanation: All the stresses that have acted on the rocks during their folding are generally absorbed by these rocks by undergoing strain. Enough stored energy is released as soon as the excavations are made and this leads to rock bursts.

7. What is affected when the layers of undesirable nature are encountered?
a) Project cost
b) Time schedule
c) Safety of the project
d) All the three are affected

Answer: d
Explanation: Same layers may be repeated along an alignment or one or more encountered layers are of undesirable nature, the project cost may be affected as also the time schedule and safety of the project.

8. Axial zones are the places of maximum concentration of stresses.
a) True
b) False

Answer: a
Explanation: Folding is the response of the rocks to the stresses induced during the process. These stresses are often strong enough to break or shatter the rocks, especially in the axial zones, which are the places of maximum concentration of these forces.

9. Shattering makes the rocks ___________
a) Non-porous
b) Impervious
c) Stronger
d) Pervious

Answer: d
Explanation: Shattering effect is of utmost importance because shattered rocks become: weak in strength parameters of all types; porous and pervious in character.

10. The axial regions have to be avoided and there is no alternative method to utilize the place.
a) False
b) True

Answer: a
Explanation: Axial regions should be thoroughly studied and avoided if possible. If it is not possible to avoid them, these areas must be subjected to suitable processes of rock treatment for developing in them desired qualities of strength and imperviousness.