Engineering Geology Multiple Choice Questions on “Monitoring and Control of Mass Movements”.
1. Which of the following is not a method of control of mass movement?
a) Afforestation
b) Retaining wall
c) Chemical treatment of rocks
d) Deforestation
Answer: d
Clarification: The widely adopted methods for control of mass movements include, construction of retaining walls, chemical treatment of rocks, rock bolting and to some extent afforestation can avoid mass movements, but, deforestation promotes mass movements.
2. While devising a monitoring system, what has to be kept in mind?
a) Factor of safety
b) Cost-benefit ratio
c) Stress factor
d) Dip factor
Answer: b
Clarification: In devising a monitoring system, the cost-benefit ratio has to be kept in mind in all the cases because such systems are invariably expensive.
3. Which of the following might not reduce the chances of infiltration?
a) Cooling the slope material
b) Oiling the surface of slopes
c) Electro-osmosis of the slope material
d) Heating of the slope material
Answer: a
Clarification: Oiling of the slope surfaces, electro-osmosis and heating of the slope material have been also used in different countries to stabilize slopes by reducing chances of infiltration during heavy rains.
4. Retraining structures may prove exceptionally successful when?
a) The ground is too fine
b) The sliding mass is likely to remain wet
c) The movement is of deep nature
d) The sliding mass is likely to remain dry
Answer: d
Clarification: Retaining structures may prove exceptionally successful where- the ground is neither too fine nor too plastic; the sliding mass is likely to remain dry and the movement is of a shallow nature and limited extent.
5. When might the retaining walls prove to be not costly?
a) When the movement is of deep nature
b) When the movement is of unlimited nature
c) When the movement is shallow in nature
d) When the rocks are too heavy
Answer: c
Clarification: Retaining walls may prove costly failures when they are designed to resist slides of great volume and thickness or long rising slopes.
6. Pneumatically applied mortar or concrete is called __________
a) Grout
b) Gunite
c) Geo-polymer concrete
d) Geniter
Answer: b
Clarification: Gunite, is pneumatically applied mortar or concrete. The mixture of cement and sand (1:3) with little water is applied on the face under pressure and is known to develop sufficient strength on settling and hardening.
7. Which of the following is not a method of slope treatment?
a) Providing drainage systems
b) Flattening the slope
c) Decreasing the load
d) Digging rock traps
Answer: a
Clarification: Usually the slope treatment methods include, flattening the slope to ensure stable limits, decreasing the load and also digging rock traps in the form of ditches at the foot of a slope and providing benches at proper intervals. Providing a drainage system is a drainage method.
8. Which type of trees and plants are more effective in reducing infiltration?
a) Tropical
b) Deciduous
c) Temperate
d) Plantation
Answer: b
Clarification: Afforestation of potentially unstable slopes reduces the risk of their failure considerably. Vegetation cover, especially of deciduous trees and plants reduces the quantity of infiltration.
9. More often a combination of methods may have to be used for stabilising the slopes.
a) True
b) False
Answer: a
Clarification: While devising a slide-control program for an unstable area, it is always useful to weigh relative merits of methods available. More often, it may be a combination of methods rather than a single method that may have to be used for stabilising the slope.
10. Removal of water is done only by subsurface drainage.
a) True
b) False
Answer: b
Clarification: Drainage involves the removal of water from within the mass as well as preventing any further water reach the material susceptible to failure. This may be achieved either by surface drainage or by subsurface drainage or by both methods.