PowerPoint Presentation
Group MembersAli Asghar 13 C 842Hafiz Zain Akram 13 C 826M.Farhan 13 C 832
DAM & RESERVOIR STRUCTURE
INTRODUCTIONDamA dam is a hydraulic structure of fairly impervious material built across a river to create a reservoir on its upstream side for impounding water for various purposes.
ReservoirA reservoir is a man-made lake that is primarily used for storing water which is located at the back side of Dam.
A dam and a reservoir are complements of each other.
A VIEW OF TARBELA DAM
Purpose of DamsGeneration of hydropower electricityFor agricultural & irrigation purposesFor fisheryTo prevent the floodingTo diverse the water
Generation of Hydroelectric Power
Irrigation Purpose
Dam prevents flood
Water Diversion
Components of DAM
Components of DamAbutmentThe part of a valley side (wall) against which a dam is constructed. An artificial abutment is sometimes constructed as a concrete gravity section, to take the thrust of an arch dam where there is no suitable natural abutment. Right and left abutments are those on respective sides of an observer looking downstream.
Abutments
Components of DamGalleryA passageway within the body of a dam or abutment; hence the terms "grouting gallery", "inspection gallery", and"drainage gallery".
A long and rather narrow hall; hence the following terms for a power plant: "valve gallery", "transformergallery", and "busbar gallery
SpillwayA structure over or through which flood flows are discharged.Controlled SpillwayIf the flow is controlled by gates, it is called a controlled spillwayUncontrolled SpillwayIf the elevation of the spillway crest is the only control, it is called an uncontrolled spillway
Fig - 1Fig - 2
Components of Dam
Types of Spillway
Auxiliary SpillwayBell mouth spillwayFuse Plug SpillwaySiphon SpillwayComponents of Dam
Auxiliary Spillway
A dam spillway built to carry runoff in excess of that carried by the principal spillway; a secondary spillway designed to operate only during exceptionally large floods. Also referred to as Emergency Spillway
Components of Dam
Bell mouth spillway
Some spillways are designed like aninverted bellso that water can enter all around the perimeter.Components of Dam
Fuse Plug Spillway
Afuse plugis a collapsible dam installed onspillwaysindamsto increase the dam's capacity.
Components of Dam
Asiphonmakes use of the difference in the height between the intake and the outlet to create a pressure difference needed to remove excess water.Siphon Spillway
Components of Dam
Crest: The top of the Dam. These may in some cases be used for providing a roadway or walkway over the dam.
Parapet walls: Low Protective walls on either side of the roadway or walkway on the crest.
Heel: Portion of Dam in contact with ground or river-bed at upstream side.
Toe: Portion of dam in contact with ground or river-bed at downstream side.
Components of Dam
Sluice way: Opening in the dam near the base, provided to clear the silt accumulation in the reservoir.
Free board: The space between the highest level of water in the reservoir and the top of the dam.
Dead Storage level: Level of permanent storage below which the water will not be withdrawn.
Components of Dam
Energy Dissipation components + Foundation Treatments of DAM
Components of DamEnergy DissipationStilling BasinA basin constructed to dissipate the energy of fast-flowing water, e.g., from a spillway or outlet, to prevent undercutting of the dam and to protect the streambed from erosion.In latest techniques some spillways are design in such a manner that do not required stilling basin. Example: Ohio Dam USA
Stilling Basin Hydraulic Jump
Downstream of OhioDamSpillway
Components of DamEnergy DissipationStilling Basin ContinueCertain auxiliary devices are usually provided in stilling basins to reduce the length of the jump.Chute BlocksBaffle wallsSillsThese devices also improve the dissipation action of the basin & stabilize the jump.
Components of DamEnergy DissipationChute BlockInstalled at the toe of spillwayFurrow the incoming jetBaffle BlockInstalled at the mid of stilling basinIncrease the turbulenceDentated SillsInstalled at the end of stilling basinDecrease the velocity of jet
Energy Dissipators
Water striking on Buffle block
Chute spillway with Buffle Blocks
Foundation Treatment Techniques for DamsVarious techniques are used for foundation treatment of dams, The most common techniques are as follows:GroutingHoles are drilled at shallow as well as deep and cement grouting is filled to establish an effective barrier to seepage under the dam and to consolidate the foundation.Consolidation GroutingCurtain Grouting
GroutingConsolidation GroutingLow-pressure grouting to fill voids, fracture zones, and cracks at and below the surface of the excavated foundation is accomplished by drilling and grouting relatively shallow holes.
Consolidation Grouting
GroutingCurtain GroutingConstruction of a deep grout curtain near the heel of the dam to control seepage is accomplished by drilling deep holes and grouting them using higher pressure.
Curtain Grouting
Why Grouting Important
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