15 Questions
Which failures are considered in dam safety analysis? (Select all that apply)
Tension
What type of dams transfer water load to abutments?
Arch dams
What are some factors that can affect dam stability?
Various factors can affect dam stability including design, construction materials, environmental conditions, and potential seismic activity.
Match the software application with its use in hydraulic structures:
RS-DAM, TADAM, CADAM2D = Dam stability analysis Geo-Studio, ANSYS = Seismic analysis HEC-RAS = Sedimentation modeling
Type of dam where the forces acting on the dam are transmitted onto the abutment rocks is?
Arch dam
Which type of dam usually has a triangular profile and can resist the forces by its own weight?
Gravity dam
Which failure occurs when the net horizontal force above any plane in the dam or at the base of the dam exceeds the frictional resistance developed at that level?
Sliding
The maximum compressive stresses occur at toe when the reservoir is _____
Full
An elementary profile of a gravity dam is the theoretical shape of its cross-section when subjected to self weight, water pressure, and uplift pressure. It has zero top width and no free board. This is known as ___________.
Elementary profile
What is the recommended formula for top width of a very low dam?
T = 0.2H + 3
The maximum quantity of water that is estimated to remain available in a storage reservoir for supply; even during worst dry periods, is known as its:
firm yield
In a hydropower station, if water is available at a rate of 175 m3/s under a head of 18 m and the turbines run at 150 rpm with an efficiency of 82%, how many turbines are required?
2
Match the following components with the hydropower plant: (Choose the correct pairings)
Storage Reservoir and dam = Stores water for energy production Forebay and Intake Structures = Receives water for turbines Head Race or Intake Conduits = Channel water to turbines Surge Tank = Controls flow stability Turbines and Generators = Convert water energy to electricity Power House = Energy generation location Tail Race and Draft Tube = Release water after energy extraction
Which classification criterion categorizes hydropower plants based on capacity?
Small to Medium < 60 MW
Does falling water spinning the water turbine represent the basic principle of hydroelectric power plants?
True
Study Notes
Design of Dams Stability
- Arch dams transfer water load to abutments using various design methods.
- Gravity dams are susceptible to failure modes including overturning, sliding, compression, and tension failures.
Dam Safety Analysis
- Dam stability is affected by several factors, making regular instrumentation and monitoring crucial.
- Safety analysis involves assessing the risks of overturning, sliding, compression, and tension failures.
Hydropower Design
- A hydropower plant consists of multiple components, including turbines, generators, and transformers.
- Power generation can be calculated using specific speed, flow rate, and head.
- Hydropower plants are classified into types based on head (high, medium, low) and load (peak, base, run-of-river).
Software Applications
- RS-DAM, TADAM, and CADAM2D are software applications used to analyze dam stability.
- Geo-Studio and ANSYS are utilized for seismic analysis, while HEC-RAS is used for sedimentation modeling.
Hydraulic Structures-I
Design of Dams
- The stability of dams depends on the self-weight and arch action
- Types of dam failures:
- Overturning
- Sliding
- Crushing
- Tension
- Factors affecting dam stability:
- Load distribution
- Compressive stresses
- Shear friction factor
Arch Dams
- Types of arch dams:
- Constant angle arch dam (for V-shaped valleys)
- Constant radius arch dam (for U-shaped valleys)
- Design methods:
- Thin cylinder theory
- Thick cylinder theory
- Elastic arch theory
- Trial load analysis (most accurate)
- Finite element method
- Best design of an arch dam: load divided between arches and cantilevers
Gravity Dams
- Types of gravity dam failures:
- Overtopping
- Seepage
- Structural failure
- Criteria for design of earth dams:
- Sufficient spillway capacity and freeboard
- Controlled seepage flow
- Formula for top width of a very low dam: T = 0.2H + 3
Dam Appurtenant and Outlet Structures
- Appurtenant structures: features of a dam, such as outlets, spillways, and intake structures
- Spillway types:
- Ogee spillway
- Trough spillway (chute spillway)
- Straight drop spillway
- Energy dissipaters: devices designed to minimize flow velocity and prevent erosion
Dam Safety: Instrumentation, Monitoring, and Surveillance
- Instrumentation of dams: devices to measure safety parameters
- Monitoring and surveillance: evaluating dam performance and detecting early signs of abnormal behavior
- Factors to check for dam safety:
- Water level and storage
- Seepage and infiltration
- Deformation and displacement
- Pore water pressure and weather conditions
Hydropower Plant
- Types of hydropower plants:
- Run-of-river plants
- Storage plants
- Pump storage plants
- Diversion canal plants
- Mini and micro-hydel plants
- Components of a hydropower plant:
- Storage reservoir and dam
- Forebay and intake structures
- Head race or intake conduits
- Surge tank
- Turbines and generators
- Power house
- Tail race and draft tube
Dam Engineering Software
-
Software for design and analysis of dams:
- RS-DAM
- TADAM
- CADAM2D
- GeoStudio
- ANSYS
- Geo5### Hydropower Plant Design and Analysis
-
HYDRA is used to determine the capacity of hydropower plants that utilize discharge, and to calculate optimal design parameters for hydropower plants.
-
HYDRA is also used to model 3D turbine component models.
Structural Analysis of Dams
- Staad Pro V8i Software is used for gravity dam design and stability analysis, and is one of the most widely used structural analysis software for dams.
- Staad Pro V8i Software is capable of 3D modeling and analysis of gravity dams using solid elements.
Sedimentation Analysis
- HEC-RAS model is used to simulate sedimentation processes resulting from hydropower development, and estimates the rate of sediment load yield (tons) and runoff (m3/s) in the sub-basin.
- Sedimentation can affect hydropower production due to loss of reservoir storage and/or damage to the facility's mechanical components.
- HEC-HMS computes watershed sediment yield using the Modified Universal Soil Loss equation.
- Desilting basins are used to remove silt/sand particles entering the water conductor system.
Seismic Instrumentation and Monitoring
- GeoSIG is a seismic instrumentation and monitoring system that helps reduce risks and costs, and avoids disasters by providing early damage detection notifications.
- The system rapidly evaluates structural response, providing a useful measure for decision-making on whether to allow normal operation or initiate a more comprehensive inspection.
Dam Monitoring
- DAMSAT harnesses satellite technology to remotely monitor water and tailings dams.
This quiz covers the design and safety aspects of hydraulic structures, including arch dams, gravity dams, and hydropower plants. It includes topics such as dam stability, failure modes, and instrumentation and monitoring.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
