EARTH DAMS
The dams which are build of rock, gravel, sand, silt or clay in various combinations by placing rolling or tamping these materials, are called earth dams or non rigid dams.
Advantages of Earth Dams :
In-spite of the structural incompressibility of earth and water many earth dams have been constructed with various types of earth and rock with stable conditions. The main advantages of earth dams are
1. Availability of Earth materials
2. Earth can be excavated, transported,compacted, with machineries easily
3. Earth dams are suited to the sites where a masonry dam cannot be used for structural reasons. These dams can be constructed even on compressible foundation. The intensity of foundation stress
due to earth is less than that due to solid masonry. The horizontal water pressure on the dams, is distributed over greater area because of greater base width and hence, the danger of sliding on a weak foundation is minimised.
4. The most important advantage of an earth dam instead of masonry, is its lesser cost, It has been observed that the total cost of an earth dam, is roughly one half of concrete dam.
Disadvantages:
However the earth and rock fill dams possess the following disadvantage
1. Non availability of the materials at or near the dam site
2. The grater maintenance cost as compared to good concrete dam
3. Earth dams are unsuitable for spill ways
Components of Earth Dams :
An Earth Dam consist of three basic components they are
1. Foundation
2. Core or Membrane
3. Shell
1. Foundation : It consist of either earth or rock and provides the support for the embackment and resist both vertical and horizontal loads. It also resist the seepage on the flow of water beneath the dam.
2. Core or Membrane : It holds back the free water of the dam reservoir. It is located either at the centre or upstream from the centre of the dam. In case of rock fill dams the core is provided on the upstream face.
3. Shell : It provides structural support for the core and distributed the load over the foundation, The dams which are constructed of the same materials are called homogeneous dams.
The dams which are build of rock, gravel, sand, silt or clay in various combinations by placing rolling or tamping these materials, are called earth dams or non rigid dams.
In-spite of the structural incompressibility of earth and water many earth dams have been constructed with various types of earth and rock with stable conditions. The main advantages of earth dams are
1. Availability of Earth materials
2. Earth can be excavated, transported,compacted, with machineries easily
3. Earth dams are suited to the sites where a masonry dam cannot be used for structural reasons. These dams can be constructed even on compressible foundation. The intensity of foundation stress
due to earth is less than that due to solid masonry. The horizontal water pressure on the dams, is distributed over greater area because of greater base width and hence, the danger of sliding on a weak foundation is minimised.
4. The most important advantage of an earth dam instead of masonry, is its lesser cost, It has been observed that the total cost of an earth dam, is roughly one half of concrete dam.
Disadvantages:
However the earth and rock fill dams possess the following disadvantage
1. Non availability of the materials at or near the dam site
2. The grater maintenance cost as compared to good concrete dam
3. Earth dams are unsuitable for spill ways
Components of Earth Dams :
An Earth Dam consist of three basic components they are
1. Foundation
2. Core or Membrane
3. Shell
1. Foundation : It consist of either earth or rock and provides the support for the embackment and resist both vertical and horizontal loads. It also resist the seepage on the flow of water beneath the dam.
2. Core or Membrane : It holds back the free water of the dam reservoir. It is located either at the centre or upstream from the centre of the dam. In case of rock fill dams the core is provided on the upstream face.
3. Shell : It provides structural support for the core and distributed the load over the foundation, The dams which are constructed of the same materials are called homogeneous dams.
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