1. Define Gravity Dam.

Ans:

A gravity dam is an Engineering structured that is by its own weight, resists the forces imposed with a desired factor of safety.

2. What are the classifications of gravity dam?

Ans:

They are classified according to the material used for constructing them:
1. Masonry Dam
2. Concrete Dam

3.What are the forces acting on a gravity dam?

Ans:

1. Water pressure
2. Weight of dam
3. uplift pressure
4. pressure due to earthquack
5. ice pressure
6. wave pressure
7. silt pressure
8. wind pressure

4.Define Uplift pressure.

Ans: The uplift pressure is defined as the upward pressure of water as it flows or seeps through the body of the dam or its foundation.

5.What are the effects of horizontal earthquake acceleration?

Ans: Horizontal acceleration due to earthquake cuses two effects:
1. Inertia force in the body of the dam
2. Hydrodynamic Pressure of Water

6.What are the modes of failure in Gravity Dam?

Ans:

following are the modes of failure in Gravity Dam: 1. Overturning
2. Sliding
3. Compression or crushing
4. Tension

7.What are the different methods of stability analysis in Gravity Dam?

Ans: The Various Method of stability analysis :
1. Gravity method or Two dimensional method:
a) Graphical method
b) Analytical method
2. Trial load twist method
3. Slab analogy method
4. Lattice analogy method
5. Experimental method
a) Direct Method
b) Indirect method

8.Differentiate between Gravity Dam and Earthen Dam.

Ans:

Parameters	Earthen dam	Gravity dam
Seepage	1.More seepage	1.Less seepage
Foundation	2.Suitable almost on any foundation	2.Suitable only when foundation is of solid rock having no fissures, cracks, cavities, etc.
Construction	3.Construction materials are stone, earth containing silt, clay and sand.	3.Construction materials are stone, brick, concrete, etc.
Maintenance	4.More costly.	4.Less costly.

9.Explain Advantages of Gravity dam.

Ans: The gravity dams possess the following advantages:
1.These are more suitable in steep valleys where earth dams may tend to slip.
2. In these dams, surplus water may be discharged through the sluices provided in the body of the dam or over spillway built in a suitable location of the dam.
3. Such dams, when built on strong foundation, may be built upto a maximum practical height.
4. A gravity dam does not fail suddenly. Their failure can be predicted well in advance so that loss of life and property may be saved.
5. Their cost of maintenance is least and benefit of cost ratio is highest.
6.These are found more advantageous in the regions of high rainfall and heavy snowfalls.
7.In these dams, sedimentation of the reservoir, may be cleared through deep set sluices.

10.Explain Disadvantages of Gravity dam.

Ans: The following are the disadvantages of a gravity dam:
1. Their initial cost of construction is high.
2. Their construction period is comparatively more.
3. These require a strong and sound foundation.
4. Dams once constructed, cannot be raised further.
5. For the supervision of concrete dams, skilled labor is required.