Dams

transcript

ContentsDams & its typesRock fill damDifference b/w earth fill & rock fill

damTypes of rock fill damCross section of rock fill damClassification of earth dam.

A dam is a structure built across a stream, river or estuary to retain water.

Dams are made from a variety of materials such as rock, steel and wood.

Gravity damIt is a solid concrete structureHaving a triangular profileDesigned that it can safely stand

against the volume of water by virtue of its weight.

Concrete masonry damsrequires great quantities of material

for construction.

Gravity dam

Buttress damsButtress dams are derived from

gravity dams.Uses thin concrete slab which is

supported from downstream side by buttresses.

It uses multiple reinforced columns to support the dams.

Relatively thin structureAmount saving of concrete material

Buttress dams

Arch DamsConcrete or masonry dams which are curved

This shape helps to transmit the major part of the water load to the abutments

Commonly built across narrow, deep river gorges.

Also considered even for little wider valleys.

Arch Dams

Beavers Dam Roddents

Beavers and their dams play an important role in nature

By constructing dams they create wetlands

lush environments which Attract fish, ducks, frogs and other

creatures

Beavers Dam

Hoover DamTalles t dams

almost 700 feets high

At the base, it is an amazing 660 feet thick and at the top it is 45 feet thick

Hoover Dam

Rock fill damA rock fill dam is built of rock

fragments and boulders of large size.

The impervious zone may be on the upstream face and made of masonry, concrete, plastic membrane, steel sheet piles, timber or other material.

Rock fill damThe impervious zone may also be

within the embankment in which case it is referred to as a core.

In early rock fill dams, steel and timber membrane were also used, but now they are obsolete.

Rock fill dam

Cross section of rock fill dam

Difference of Rock fill & earth fill dam Earth fill Rock fill

01 An earth dam is made of earth soil

A rock fill dam is built of rock fragments of large size

02Earth dams are relatively

smaller in height Rock fill dams have more height than earth fill dam based on its foundation

They can be built on all types of foundation

Rockfill dams require foundation stronger than those

for earth dams.

04 They are mainly built with clay, sand

They are mainly built with gravel, and rocks from

mountains or river. 05 Local available soil is the

main source of construction

The material is to be collected from different

places

Classification of earth fill dams

Based on the method of construction:

Rolled fill earth dams

Hydraulic fill dam

Based on mechanical characteristics of earth

materials making the section of the Dam

Homogeneous earth dams

Non-Homogeneous (zoned) earth dams

Homogeneous sections are constructed with one type of soil.

The soil should have frictional resistance as well as low permeability and should be available in required quantities near site. Such sections are not in common practice.

This type of dams are generally used

The casing is made of sand and gravel or soft rock etc. It provides stability to the dam section.

In the most of the dam sites, clayey silts, gravelly deposits are available and all such local materials can be used in zoned type embankments

Kalabagh Dam

References

http://animals.howstuffworks.com/mammals/beaver-dam.htm

http://www.civileblog.com/types-of-dams/

http://science.howstuffworks.com/engineering/structural/hoover-dam-broke.htm

Dams

Engineering