Model Answer
0 min readIntroduction
Buttress dams are gravity dams that utilize buttresses to reduce the volume of concrete required. Unlike conventional gravity dams which resist water pressure through their weight, buttress dams transfer the load to a foundation through a series of supporting buttresses. These dams are particularly useful in situations where the foundation is strong but the available material for constructing a massive concrete structure is limited. They are a cost-effective alternative to gravity dams in suitable geological settings, especially in narrow canyons.
Components of a Buttress Dam
A typical buttress dam consists of three main components:
- Deck: The upstream water-retaining surface, usually a thin concrete slab.
- Buttresses: Inclined supports that transmit the water load to the foundation. These can be triangular, arched, or flat.
- Foundation: The bedrock or competent soil layer that supports the entire structure.
Types of Buttress Dams
Buttress dams are classified based on the buttress design:
- Triangular Buttress Dams: Most common type, offering good stability.
- Arched Buttress Dams: Utilize arch action to further reduce concrete volume.
- Flat Buttress Dams: Less common, suitable for wider valleys.
Advantages & Disadvantages
| Advantages | Disadvantages |
|---|---|
| Less concrete required than gravity dams. | More susceptible to damage from erosion at the base. |
| Suitable for wide valleys with strong foundations. | Requires a strong and stable foundation. |
| Easier to repair than gravity dams. | More complex design and construction. |
Geologically, the foundation must be competent and impermeable to prevent seepage and ensure stability. Site investigation is crucial before construction.
Conclusion
Buttress dams represent an efficient alternative to conventional gravity dams, particularly in areas with strong foundations and limited concrete resources. Their design necessitates careful geological investigation and construction techniques to ensure long-term stability and prevent seepage. While offering economic advantages, their susceptibility to erosion and complex construction require diligent monitoring and maintenance.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.