Each type of dam has its own advantages and is chosen based on factors such as the topography of the site, available construction materials, and the specific requirements of the project. The selection of the dam type depends on a comprehensive engineering analysis of the site and its surrounding conditions.
Types of Dams
- Embankment Dams:
Embankment dams, also known as earthfill dams or rockfill dams, are constructed using compacted earth or rock materials. They are the most common type of dams worldwide. The basic structure consists of an impervious core made of clay or concrete, which is surrounded by compacted earth or rock fill on both the upstream and downstream sides. The embankment dam relies on the weight of the fill material to resist the force of water pressure. - Gravity Dams:
Gravity dams are built using rigid materials such as concrete or masonry. They are designed to resist the horizontal thrust of water by their sheer weight and strength. The dam’s mass resists the force exerted by the water, preventing its flow. Gravity dams are typically wide at the base and narrow at the top, allowing the weight of the structure to transfer the water’s force into the ground. The force of gravity provides stability to the dam against the water pressure. - Arch Dams:
Arch dams are curved structures that rely on their shape to transfer the water’s force to the abutment walls on either side of the river or valley. The curved design allows the weight of the water to be transferred horizontally to the foundation and abutments, which counteract the outward thrust. Arch dams are typically constructed using materials like concrete and are ideal for narrow canyons or valleys where the abutments can support the horizontal forces. - Buttress Dams:
Buttress dams are a type of arch dam where the arch is supported by a series of reinforced concrete buttresses or supports on the downstream side of the dam. The buttresses resist the horizontal thrust of water by transmitting it to the foundation or abutments. Buttress dams are suitable for wider valleys where the abutments alone may not be able to withstand the water pressure. The arrangement of buttresses creates a series of triangular sections that provide the necessary stability.
General View of each Dam risks
Here’s a general ranking of construction and operation risks for each type of dam:
Embankment Dams:
Construction Risks:
- Seepage and piping through the embankment material
- Inadequate compaction leading to settlement or deformation
- Stability issues during construction due to weak foundation or slope failures
- Construction material availability and quality control Operation Risks:
- Seepage and erosion through the embankment or foundation
- Overtopping and potential breach during flood events
- Inadequate maintenance leading to vegetation growth and erosion
- Reservoir sedimentation affecting storage capacity
Gravity Dams:
Construction Risks:
- Proper concrete placement and curing to avoid cracking or structural issues
- Foundation preparation and stability concerns
- Construction joint integrity
- Quality control of materials and construction techniques Operation Risks:
- Seepage and leakage through joints or cracks in the concrete
- Structural stability and potential sliding or overturning
- Reservoir sedimentation reducing storage capacity
- Aging and deterioration of concrete over time
Arch Dams:
Construction Risks:
- Proper foundation preparation and stability
- Precise construction of the curved shape and proper alignment
- Control of thermal stresses during concrete curing
- Quality control of materials and construction techniques Operation Risks:
- Seepage and leakage at the abutments or through foundation rocks
- Potential for arch deformation or cracking
- Reservoir sedimentation affecting storage capacity
- Aging and deterioration of concrete over time
Buttress Dams:
Construction Risks:
- Proper construction of buttresses and their connection to the dam
- Stability of the abutments and foundation
- Quality control of materials and construction techniques
- Potential for differential settlement Operation Risks:
- Seepage and leakage through the buttresses or abutments
- Structural stability of the buttresses
- Reservoir sedimentation reducing storage capacity
- Aging and deterioration of concrete over time
It’s important to note that these rankings are general and can vary depending on the specific circumstances of each dam project. Engineering studies, risk assessments, and continuous monitoring are essential to minimize and manage risks throughout the construction and operation phases of a dam.
Please refer to this article to know more about the risk management and insurance of dam collapse