Types of Dams ppt

8/19/2019 Types of Dams ppt

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DAMS


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Dams

Dam is a solid barrier constructed at asuitable location across a river valley tostore fowing water.

Storage of water is utilized for following objectives:

Hydropower Irrigation Water for domestic consumption Drought and ood control

or navigational facilities !ther additional utilization is to develop

"sheries


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Structure ofDam

Heel

Gallery

Toe

Spillway(inside dam)

Crest

NWL

Normal

water level

MWL

Max. level

Free boardSli!e way

Upstream Down stream


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Heel: contact with the ground on the upstream side

Toe: contact on the downstream side

Abutment: Sides of the valley on which the structure of the damrest

Galleries: small rooms like structure left within the dam forchecking operations.

Diversion tunnel: Tunnels are constructed for diverting waterbefore the construction of dam. This helps in keeping the riverbed dry.

Spillways: t is the arrangement near the top to release thee!cess water of the reservoir to downstream side

Sluice way: An opening in the dam near the ground level" whichis used to clear the silt accumulation in the reservoir side.


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#$%&S !D'(S Gravity Dams:

These dams areheavy and massivewall-like structuresof concrete in which

the whole weightacts verticallydownwards

"eservoir

For!e

#s t$e entire load is transmitted on t$e small area o% %ondation& s!$dams are !onstr!ted w$ere ro!'s are !ompetent and stable.


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Bhakra Dam is thehighest ConcreteGravity dam in Asiaand Second ighest inthe world!

Bhakra Dam is acrossriver Sutle" in imachal#radesh

The construction of this

$ro"ect was started inthe year %&'( and wascom$leted in %&)* !

t is *+, %t. $i-$ above t$e deepest %ondation as strai-$t !on!rete dam bein- more t$an t$ree times

t$e $ei-$t o% tab Minar.

Len-t$ at top /01.02 m (0*,, %eet)3 Widt$ at base 04,./ m (25/ %eet)& and at t$e top is 4.0+ m (6,%eet)

Bhakra Dam is the highest Concrete Gravity dam in Asia and Second Highest in the world.


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)uttressDam:

Buttress Dam + ,s agravity damreinforced ystructural su$$orts

Buttress - a su$$ortthat transmits aforce from a roof orwall to another

su$$orting structureT$is type o% str!tre !an be !onsidered even i% t$e %ondation

ro!'s are little wea'er


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These ty$e of dams are

concrete or masonrydams which are curved orconve. u$stream in $lan

This sha$e hel$s totransmit the ma"or $art ofthe water load to theautments

Arch dams are uilt acrossnarrow, deep rivergorges, but now inrecent years they havebeen considered evenor little wider valleys.

Arch Dams:


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/arthDams:

They are tra$e0oidal

in sha$e /arth dams are

constructed where thefoundation or theunderlying material orrocks are weak tosu$$ort the masonry

dam or where thesuitale com$etentrocks are at greaterde$th!

/arthen dams arerelatively smaller inheight and road atthe ase

They are mainly uiltwith clay1 sand andgravel1 hence they arealso known as /arth2ll dam or 3ock 2lldam


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3ock2ll dams

"o!'%ill dams $ave ro!'%ill materials sed to resist t$e t$rst

o% reservoir water. #n impermeable %a!in- on t$e pstream

slope or a !ore and ade7ate rbble masonry is essential toresist any destr!tive de%le!tions.


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Criteria for selection of

dam sites 4ocation of dam site to e restricted to narrow gorges with stee$

sides having hard resistant rocks!

Staility of the valley 5oor and valley slo$es de$ends on the

nature and e.tent of "ointing and 2ssures in the rocks! 3ocks should e homogenous! Modulus of elasticity should e

high!

Susurface conditions should e free from sliding1 faulting!

Tectonic conditions at the site! Seismic nature of the area!

,n the region of sedimentaries1 $articularly in limestone areas andeva$orates soil strata1 chances of failure and treatment methods

/.tent and nature of weathering on the valley surface have to eevaluated!


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Contd!!

ydrological conditions in the area1 oth at catchment andreservoir1 must e evaluated!

Availaility of suitale 6uality and 6uantity of constructionmaterial in the vicinity!

The to$ogra$hic feature of the area with its $hysiogra$hicand geological setu$ enale construction of variousancillary structures!

7or earth dam structures1 soil mechanical $ro$erties ofmaterials in and around the foundation are to e carefullyassessed

Types of Dams ppt

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