"contentUrl": "https://slideplayer.com/slide/18121137/117/images/5/Planning+for+War+Strategy+on+Enemies.jpg", It also accelerates the process of consolidation. "@context": "http://schema.org", "contentUrl": "https://slideplayer.com/slide/18121137/117/images/23/Diaphragm+Type+Embankment.jpg", When the construction of a large dam is not possible. "description": "They can be constructed on any dam site, where there is natural foundation strong enough to bear large weight of the dam. Non-Overflow dams combined together to form a composite single structure.
Seepage flow through the embankment, foundation and abutments is controlled so that no internal erosion takes place. { It is sometimes know as a thin core dam. Earthen Dam-Embankment DamDr. "@context": "http://schema.org", }, 4 Seepage control through the dam. To overcome this, stone pitching or rip rap should be provided on upstream face of dam. ", Backward extension of the filter depends upon so many factors. { Such a blanket when constructed over a pervious foundation reduces the quantity of seepage on D/S side. (Earthen Dam)
"@type": "ImageObject", { }, 34 "name": "Site Selection Criteria for Dam", Presented by: 1. Almost every type of dam can be built as it is strong enough to withstand the self weight of the dam and external forces acting on the dam.
", "@context": "http://schema.org", In such cases they seal such openings and reduce the seepage considerably. ", "@type": "ImageObject", The actuation forced and decreasing the resisting forces. Sometimes this may also cause slip of upstream slope. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/24/Failure+of+Earthen+dam+and+embankment.jpg", Blankets are particularly effective when there are cracks and fissures in the foundation beneath the dam structure. "width": "1024" "description": "Such a blanket when constructed over a pervious foundation reduces the quantity of seepage on D\/S side. Such a bean is useful in controlling seepage where D/S top strata is relatively thin and uniform or even top strata is absent. ", Sometimes this may also cause slip of upstream slope. "name": "Definition of Dam and Uses", The upstream pervious zone provides free drainage during sudden drawdown and the downstream pervious zone acts as a drain to control the phreatic line. Timber dams.
In such cases combining the spillway and dam into one structure may be desirable. Chimney drains also render earth dam earthquake resistant. They can built with natural materials and process with minimum primitive equipment.
}, 27 "name": "Structural Failure The slope fail during construction. The impervious core is made-up of impervious soils, concrete, steel, timber, or any other material. For economy, the length of the dam should be as small as possible and for given height it should store maximum amount of water. "@type": "ImageObject", The upstream pervious zone provides free drainage during sudden drawdown and the downstream pervious zone acts as a drain to control the phreatic line. "width": "1024" "width": "1024" "description": "", ", {
But this extension may at the most be up to centre line of the dam. This may be due to insufficient capacity of spillway or design without proper estimation of flood level or problem in lifting of spillway gates during flood times. "name": "Seepage Control Through the Dam", The cost of constructing a separate spillway may be enormous or sometimes suitable site for construction of spillway may not be available. The failure may cause vast damages and loss of human lives. Hollow masonry gravity dams. Chinese used to destroy their dikes to flood out enemy. "name": "Important Earth Dams of the World", D/S Seepage Berms Additional berms may be built on the D/S side of the dam in continuation of the D/S end. "description": "Such a bean is useful in controlling seepage where D\/S top strata is relatively thin and uniform or even top strata is absent.
}, 37 "name": "Due to Over-topping", Erosion at Upstream Erosion of Upstream faceThe upstream face of dam may subjected water waves which are formed due to winds and these waves notch-out the soil from upstream face which causes erosion. "name": "Seepage control in Earth Dams", Cougar Dam on Mc-Knezie River on Oregon (445\u2018 height) in USA. Where Earth materials more easily available as a building material compared to concrete or stone or rock. The various types of foundations generally encountered are :- Solid-rock foundation: Similar like granite, gneiss etc. A suitable site for the spillway should be available in or nearby vicinity. Zoned Earth Dams A zoned earth dam make up of more than one type of material. "@context": "http://schema.org", The blanket should be composed of such material which is at least 100 times less pervious than the foundation material. Methods of Construction.
"width": "1024" The safety of earth dam depends almost entirely on seepage control through dam and its foundation. Diaphragm Earth dam A diaphragm type earth consists of a thin impervious core known as diaphragm, which is previous shells. Other consideration It includes life of dam, the width of roadway to be provided over the dam, overall cost of the construction and maintenance. "@context": "http://schema.org", "width": "1024" The San Gabriel No.1 Dam (331\u2018 height) in USA. Factors affecting Selection of particular type of Dam.
The amount of ater lost through seepage must be controlled so that it does not interfere with planned project functions, Transition filters are incorporated to satisfy the two essential conditions of filters, viz., to prevent choking of the filter by soil and have minimum of head loss in the filter, Dam as a whole is earthquake resistant. { Backward extension of the filter depends upon so many factors. Gravel foundation: This type of foundation is suitable for earth and rock fill dams. Porous drains remain enclosed in gravel filters. "description": "They can built with natural materials and process with minimum primitive equipment. Rigid dams Rigid materials like masonry, concrete, steel, timber, Non-rigid dams Earth and rock fill materials. This measure is adopted when top stratum is pervious and thin. "name": "Diaphragm Earth dam A diaphragm type earth consists of a thin impervious core known as diaphragm, which is previous shells. This critical condition occurs when the reservoir is full and steady seepage is at its maximum rate. "@context": "http://schema.org", ", When the foundation strut is not sufficiently strong.
"@type": "ImageObject", "width": "1024" Height of Dam. It is always led down into the foundation from the ground surface. Nagarjuna Sagar Dam. "@type": "ImageObject",
"contentUrl": "https://slideplayer.com/slide/18121137/117/images/21/Zoned+Earth+Dams.jpg", Green Mountain Dam on Colorado River in U.S.A, Side flanks of Nagarjuna Sagar Dam in India, Maithan Dam in India (it is partly Earthen and partly Rockfill), Rockfill are formed of loose rocks and boulders piled in the river bed, A slab reinforced concrete is often laid across the upstream face of a rockfill dam to make it water tight, The Salt Springs Dam in California (345 height) in USA, The San Gabriel No.1 Dam (331 height) in USA, Cougar Dam on Mc-Knezie River on Oregon (445 height) in USA. ", The upstream and downstream pervious zone gives stability to the dam and it consists of sand, cobbles or rock or a mixture of these materials. "description": "Topography. Height of Dam. "@context": "http://schema.org", "description": "", These big dams are expensive to built but more durable and solid than earth and rock dams. "width": "1024"
The dam site should be easily accessible, such that it can be economically connected to important towns. "description": "The pore water pressure develops during and immediately after construction, especially if the construction is relatively fast. Storage dams.
Slope Protection. "description": "They reduce the sub surface uplift pressure D\/S of the dam. They reduce the sub surface uplift pressure D/S of the dam. Due to Over-topping Hydraulic failure also occurs when the water over-tops the dam crest.
}, 18 "width": "1024"
Lecture 11 Advance Design of RC Structure Retaining walls, LINTON UNIVERSITY COLLEGE SCHOOL OF CIVIL ENGINEERING. Selection of Type of DamTopography A narrow U-shaped valley flowing between high rocky walls would suggest a concrete dam. These above three dams are well found in ancient days. ", Dams are frequently opened in times of war. General view of an Earthfill dam If dam is located in earthquake zone, its design must include the earthquake forces.
These above three dams are well found in ancient days. Upstream slope is safe against rapid drawdown conditions while the downstream slope is safe against sloughing. }, 42 Seepage line, i.e., phreatic line is well within the downstream face so that no sloughing of the slope takes place. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/41/Upstream+Impervious+Blanket.jpg", A 90%depth of cut-off reduces about 25% seepage. "width": "1024" Types of Earthen Dams Homogeneous Embankment type Zone embankment typeDiaphragm type Homogeneous Embankment Type. At the back of this barrier water gets collected forming a pool of water. "name": "Seepage Control Through the Foundation", "name": "Design Criteria for Earth Dams",
Failed during sudden drawdown conditionThe most critical condition occurs when the reservoir suddenly gets empty without allowing appreciable drainage from the saturated soil mass. A suitable site for the spillway should be available in or nearby vicinity. Top of impervious core is maintained higher than the maximum reservoir level, Seepage line, i.e., phreatic line is well within the downstream face so that no sloughing of the slope takes place, Seepage flow through the embankment, foundation and abutments is controlled so that no internal erosion takes place. "width": "1024" Various causes by the failure of earth dam may group Hydraulic failure-35% Seepage failure-38% Structural failure-7%. Upstream Impervious BlanketSuch a blanket when constructed over a pervious foundation reduces the quantity of seepage on D/S side. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/30/Failed+during+sudden+drawdown+condition.jpg", ", Chimney drains also render earth dam earthquake resistant. Hydraulic Failures of Earthfill Dams4 out every 10 earthen dams have failed due to hydraulic failures. These above three dams are well found in ancient days. "@type": "ImageObject", "width": "1024"
Relief Well It is such a well which if not constructed would cause formation of sand boils and possibly sub-surface piping. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/10/Classification+of+the+Type+of+Dam+and+Their+Classifications.jpg", "name": "Uses Irrigation Drinking purpose Recreation uses Industrial Needs", }, 2 "name": "", "contentUrl": "https://slideplayer.com/slide/18121137/117/images/27/Erosion+of+Downstream+toe.jpg", "contentUrl": "https://slideplayer.com/slide/18121137/117/images/28/Due+to+Over-topping.jpg", "@context": "http://schema.org", It includes life of dam, the width of roadway to be provided over the dam, overall cost of the construction and maintenance. Earthquake zone. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/38/D%2FS+Seepage+Berms+Additional+berms+may+be+built+on+the+D%2FS+side+of+the+dam+in+continuation+of+the+D%2FS+end..jpg", "description": "Selection of Type and their Classification. It acts as a water barrier to prevent seepage through the dam. Earthen dams and earthen levees are the most ancient type of embankments. {
"name": "Spillway size and location", "@context": "http://schema.org", Hence the dam site must be surveyed by geologists so as to detect the thickness of foundation strata, presence of faults, fissured material etc. Upstream slope is protected against erosion by wave action while the crest and downstream slope is protected against erosion due to wind and rain. To overcome this, stone pitching or rip rap should be provided on upstream face of dam. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/16/Earthen+Dams+Earthen+dams+and+earthen+levees+are+the+most+ancient+type+of+embankments..jpg",
The transition filters prevent the migration of the core material into the pores of the previous zone material. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/31/Design+Criteria+for+Earth+Dams.jpg", flows continuously throughout the year), then in such a situation, the earth is more favourable for dam construction. On the other hand, if the thickness of the core equals or exceeds those limits. Porous drains remain enclosed in gravel filters. "@context": "http://schema.org", "name": "Erosion at Upstream Erosion of Upstream face",
{ To prevent cross currents from spillway, sidewalls of spillway should be constructed with adequate height and length. Horizontal Drainage FilterIt is provided at the base of the dam, starting from down stream end of the dam and extending backwards into the dam. A measure of how easily a fluid (e.g., water) can pass through a porous medium (e.g., soils) 2 Loose soil - easy to flow - high permeability. }, 35 { The downstream transition filter is useful during the steady seepage condition. A narrow U-shaped valley flowing between high rocky walls would suggest a concrete dam.
Non-Overflow dams \u2013 Many times Overflow dams and. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/18/Conditions+favouring+an+earth+dam.jpg",
Due to Frost Action. To prevent over-topping of dam, adequate freeboard should be provided. This is the most common type of a role fill dam in which a central impervious core is flank shells of previous material on the upstream and downstream of the dam. It also causes reduction in uplift pressure throughout the D/S side. "@type": "ImageObject", To prevent cross currents from spillway, sidewalls of spillway should be constructed with adequate height and length. If seepage pressure at the D/S end of the dam is still excessive, the horizontal filter drain may be continued even beyond the D/S toe of the dam. ", "width": "1024" A diaphragm type earth consists of a thin impervious core known as diaphragm, which is previous shells. "description": "Suitable foundation must be available. Silt and fine sand foundation: This type of foundation suggests the adoption of earth or very low gravity dam, up to height of 8 meter. It also causes drainage of foundation. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/37/Seepage+Control+Through+the+Foundation.jpg", "contentUrl": "https://slideplayer.com/18121137/117/images/slide_42.jpg", The transition filters prevent the migration of the core material into the pores of the previous zone material. "name": "Hydraulic Failures of Earthfill Dams", ", A low-rolling plane country would suggest an earth fill dam. "@type": "ImageObject", Overflow dams - Spillways.
Seepage flow through the dam and foundation is so controlled that there is no danger of fine particles getting washed out from the downstream by the efflux of seepage. "@type": "ImageObject", "description": "The tail water present on the downstream side or cross-currents may come from spillway buckets may affects the downstream toe portion and erosion occurs. If the thickness of the diaphragm core at any elevation is less than 10 m or less than the height of the embankment above the corresponding elevation.
"name": "", They intercept the seepage through the foundation and control the outlet for seepage. The various types of foundations generally encountered are :-. The actuation forced and decreasing the resisting forces. { In recent days, four other types of dams have come into practice. The transition filters prevent the migration of the core material into the pores of the previous zone material. Chimney drain or filter, if correctly built, intercepts all the seepage from the dam regardless of the stratification in the dam. Important Earth Dams of the WorldGreen Mountain Dam on Colorado River in U.S.A Swift Dam in Washington in U.S.A Side flanks of Nagarjuna Sagar Dam in India Trinity Dam in California in U.S.A Maithan Dam in India (it is partly Earthen and partly Rockfill) If you wish to download it, please recommend it to your friends in any social system. Rock toe keeps seepage line well within the dam section. "width": "1024" Hence measures of seepage control are very important for the success of an earthen dam. In this situation, when sufficient spillway space is not available. ", Non-Overflow dams combined together to form a composite single structure. Hence for greater height, gravity dams are generally preferred. "@type": "ImageObject", "width": "1024" Factors affecting Selection of a Particular DamTopography Geology and Foundation Conditions Availability of Materials Spillway size and location Earthquake zone Height of Dam Other consideration "name": "Horizontal Drainage Filter", }, ENGINEERING GEOLOGICAL STUDIES for DAM CONSTRUCTION. Upstream slope is safe against rapid drawdown conditions while the downstream slope is safe against sloughing, Side slopes upstream and downstream are flat enough so that the shear stress-induced in the foundation is within the shear strength of the material comprising the foundation with a suitable factor of safety, Upstream slope is protected against erosion by wave action while the crest and downstream slope is protected against erosion due to wind and rain. This may be due to insufficient capacity of spillway or design without proper estimation of flood level or problem in lifting of spillway gates during flood times.
The amount of ater lost through seepage must be controlled so that it does not interfere with planned project functions, Transition filters are incorporated to satisfy the two essential conditions of filters, viz., to prevent choking of the filter by soil and have minimum of head loss in the filter, Dam as a whole is earthquake resistant. The dam site should be easily accessible, such that it can be economically connected to important towns.
Transition filters are incorporated to satisfy the two essential conditions of filters, viz., to prevent choking of the filter by soil and have minimum of head loss in the filter. Homogeneous Embankment Type. { "@context": "http://schema.org", "contentUrl": "https://slideplayer.com/slide/18121137/117/images/35/Horizontal+Drainage+Filter.jpg", }, 19 "description": "The Dutch breached their dikes during II world war to bedevil the invading Germans. To prevent this problem, stone pitching or rip rap should be provided on the downstream face of dam up to a depth of normal tail water level.
If possible, cut-off should extend upto the impervious strata lying below the ground level. }, 11 This filter controls seepage line and does not allow it to get exposed on D/S face of the dam. ", These are, Classification according to material used for dam construction, Diversion dams are also called weir or barrage, The detention dams to trap sediment- also called debris dams, Classification according to Hydraulic Designs, Non-Overflow dams Many times Overflow dams and. It includes life of dam, the width of roadway to be provided over the dam, overall cost of the construction and maintenance. It is provided at the base of the dam, starting from down stream end of the dam and extending backwards into the dam. Earthen dams are usually not provided for height more than 30 meter. It is used to prevent seepage through the foundation. }, 6 { ", Sometimes this may also cause slip of upstream slope. ", }, 40 The simplest type of an earthen embankment consists of asingle material and is homogeneous throughout. "@type": "ImageObject", The provision of U/S blanket is found economical and more effective when the depth of previous overburden is large and the provision of the cut-off wall is uneconomical.
Seepage flow through the embankment, foundation and abutments is controlled so that no internal erosion takes place. { It is sometimes know as a thin core dam. Earthen Dam-Embankment DamDr. "@context": "http://schema.org", }, 4 Seepage control through the dam. To overcome this, stone pitching or rip rap should be provided on upstream face of dam. ", Backward extension of the filter depends upon so many factors. { Such a blanket when constructed over a pervious foundation reduces the quantity of seepage on D/S side. (Earthen Dam)
"@type": "ImageObject", { }, 34 "name": "Site Selection Criteria for Dam", Presented by: 1. Almost every type of dam can be built as it is strong enough to withstand the self weight of the dam and external forces acting on the dam.
", "@context": "http://schema.org", In such cases they seal such openings and reduce the seepage considerably. ", "@type": "ImageObject", The actuation forced and decreasing the resisting forces. Sometimes this may also cause slip of upstream slope. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/24/Failure+of+Earthen+dam+and+embankment.jpg", Blankets are particularly effective when there are cracks and fissures in the foundation beneath the dam structure. "width": "1024" "description": "Such a blanket when constructed over a pervious foundation reduces the quantity of seepage on D\/S side. Such a bean is useful in controlling seepage where D/S top strata is relatively thin and uniform or even top strata is absent. ", Sometimes this may also cause slip of upstream slope. "name": "Definition of Dam and Uses", The upstream pervious zone provides free drainage during sudden drawdown and the downstream pervious zone acts as a drain to control the phreatic line. Timber dams.
In such cases combining the spillway and dam into one structure may be desirable. Chimney drains also render earth dam earthquake resistant. They can built with natural materials and process with minimum primitive equipment.
}, 27 "name": "Structural Failure The slope fail during construction. The impervious core is made-up of impervious soils, concrete, steel, timber, or any other material. For economy, the length of the dam should be as small as possible and for given height it should store maximum amount of water. "@type": "ImageObject", The upstream pervious zone provides free drainage during sudden drawdown and the downstream pervious zone acts as a drain to control the phreatic line. "width": "1024" "width": "1024" "description": "", ", {
But this extension may at the most be up to centre line of the dam. This may be due to insufficient capacity of spillway or design without proper estimation of flood level or problem in lifting of spillway gates during flood times. "name": "Seepage Control Through the Dam", The cost of constructing a separate spillway may be enormous or sometimes suitable site for construction of spillway may not be available. The failure may cause vast damages and loss of human lives. Hollow masonry gravity dams. Chinese used to destroy their dikes to flood out enemy. "name": "Important Earth Dams of the World", D/S Seepage Berms Additional berms may be built on the D/S side of the dam in continuation of the D/S end. "description": "Such a bean is useful in controlling seepage where D\/S top strata is relatively thin and uniform or even top strata is absent.
}, 37 "name": "Due to Over-topping", Erosion at Upstream Erosion of Upstream faceThe upstream face of dam may subjected water waves which are formed due to winds and these waves notch-out the soil from upstream face which causes erosion. "name": "Seepage control in Earth Dams", Cougar Dam on Mc-Knezie River on Oregon (445\u2018 height) in USA. Where Earth materials more easily available as a building material compared to concrete or stone or rock. The various types of foundations generally encountered are :- Solid-rock foundation: Similar like granite, gneiss etc. A suitable site for the spillway should be available in or nearby vicinity. Zoned Earth Dams A zoned earth dam make up of more than one type of material. "@context": "http://schema.org", The blanket should be composed of such material which is at least 100 times less pervious than the foundation material. Methods of Construction.
"width": "1024" The safety of earth dam depends almost entirely on seepage control through dam and its foundation. Diaphragm Earth dam A diaphragm type earth consists of a thin impervious core known as diaphragm, which is previous shells. Other consideration It includes life of dam, the width of roadway to be provided over the dam, overall cost of the construction and maintenance. "@context": "http://schema.org", "width": "1024" The San Gabriel No.1 Dam (331\u2018 height) in USA. Factors affecting Selection of particular type of Dam.
The amount of ater lost through seepage must be controlled so that it does not interfere with planned project functions, Transition filters are incorporated to satisfy the two essential conditions of filters, viz., to prevent choking of the filter by soil and have minimum of head loss in the filter, Dam as a whole is earthquake resistant. { Backward extension of the filter depends upon so many factors. Gravel foundation: This type of foundation is suitable for earth and rock fill dams. Porous drains remain enclosed in gravel filters. "description": "They can built with natural materials and process with minimum primitive equipment. Rigid dams Rigid materials like masonry, concrete, steel, timber, Non-rigid dams Earth and rock fill materials. This measure is adopted when top stratum is pervious and thin. "name": "Diaphragm Earth dam A diaphragm type earth consists of a thin impervious core known as diaphragm, which is previous shells. This critical condition occurs when the reservoir is full and steady seepage is at its maximum rate. "@context": "http://schema.org", ", When the foundation strut is not sufficiently strong.
"@type": "ImageObject", "width": "1024" Height of Dam. It is always led down into the foundation from the ground surface. Nagarjuna Sagar Dam. "@type": "ImageObject",
"contentUrl": "https://slideplayer.com/slide/18121137/117/images/21/Zoned+Earth+Dams.jpg", Green Mountain Dam on Colorado River in U.S.A, Side flanks of Nagarjuna Sagar Dam in India, Maithan Dam in India (it is partly Earthen and partly Rockfill), Rockfill are formed of loose rocks and boulders piled in the river bed, A slab reinforced concrete is often laid across the upstream face of a rockfill dam to make it water tight, The Salt Springs Dam in California (345 height) in USA, The San Gabriel No.1 Dam (331 height) in USA, Cougar Dam on Mc-Knezie River on Oregon (445 height) in USA. ", The upstream and downstream pervious zone gives stability to the dam and it consists of sand, cobbles or rock or a mixture of these materials. "description": "Topography. Height of Dam. "@context": "http://schema.org", "description": "", These big dams are expensive to built but more durable and solid than earth and rock dams. "width": "1024"
The dam site should be easily accessible, such that it can be economically connected to important towns. "description": "The pore water pressure develops during and immediately after construction, especially if the construction is relatively fast. Storage dams.
Slope Protection. "description": "They reduce the sub surface uplift pressure D\/S of the dam. They reduce the sub surface uplift pressure D/S of the dam. Due to Over-topping Hydraulic failure also occurs when the water over-tops the dam crest.
}, 18 "width": "1024"
Lecture 11 Advance Design of RC Structure Retaining walls, LINTON UNIVERSITY COLLEGE SCHOOL OF CIVIL ENGINEERING. Selection of Type of DamTopography A narrow U-shaped valley flowing between high rocky walls would suggest a concrete dam. These above three dams are well found in ancient days. ", Dams are frequently opened in times of war. General view of an Earthfill dam If dam is located in earthquake zone, its design must include the earthquake forces.
These above three dams are well found in ancient days. Upstream slope is safe against rapid drawdown conditions while the downstream slope is safe against sloughing. }, 42 Seepage line, i.e., phreatic line is well within the downstream face so that no sloughing of the slope takes place. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/41/Upstream+Impervious+Blanket.jpg", A 90%depth of cut-off reduces about 25% seepage. "width": "1024" Types of Earthen Dams Homogeneous Embankment type Zone embankment typeDiaphragm type Homogeneous Embankment Type. At the back of this barrier water gets collected forming a pool of water. "name": "Seepage Control Through the Foundation", "name": "Design Criteria for Earth Dams",
Failed during sudden drawdown conditionThe most critical condition occurs when the reservoir suddenly gets empty without allowing appreciable drainage from the saturated soil mass. A suitable site for the spillway should be available in or nearby vicinity. Top of impervious core is maintained higher than the maximum reservoir level, Seepage line, i.e., phreatic line is well within the downstream face so that no sloughing of the slope takes place, Seepage flow through the embankment, foundation and abutments is controlled so that no internal erosion takes place. "width": "1024" Various causes by the failure of earth dam may group Hydraulic failure-35% Seepage failure-38% Structural failure-7%. Upstream Impervious BlanketSuch a blanket when constructed over a pervious foundation reduces the quantity of seepage on D/S side. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/30/Failed+during+sudden+drawdown+condition.jpg", ", Chimney drains also render earth dam earthquake resistant. Hydraulic Failures of Earthfill Dams4 out every 10 earthen dams have failed due to hydraulic failures. These above three dams are well found in ancient days. "@type": "ImageObject", "width": "1024"
Relief Well It is such a well which if not constructed would cause formation of sand boils and possibly sub-surface piping. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/10/Classification+of+the+Type+of+Dam+and+Their+Classifications.jpg", "name": "Uses Irrigation Drinking purpose Recreation uses Industrial Needs", }, 2 "name": "", "contentUrl": "https://slideplayer.com/slide/18121137/117/images/27/Erosion+of+Downstream+toe.jpg", "contentUrl": "https://slideplayer.com/slide/18121137/117/images/28/Due+to+Over-topping.jpg", "@context": "http://schema.org", It includes life of dam, the width of roadway to be provided over the dam, overall cost of the construction and maintenance. Earthquake zone. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/38/D%2FS+Seepage+Berms+Additional+berms+may+be+built+on+the+D%2FS+side+of+the+dam+in+continuation+of+the+D%2FS+end..jpg", "description": "Selection of Type and their Classification. It acts as a water barrier to prevent seepage through the dam. Earthen dams and earthen levees are the most ancient type of embankments. {
"name": "Spillway size and location", "@context": "http://schema.org", Hence the dam site must be surveyed by geologists so as to detect the thickness of foundation strata, presence of faults, fissured material etc. Upstream slope is protected against erosion by wave action while the crest and downstream slope is protected against erosion due to wind and rain. To overcome this, stone pitching or rip rap should be provided on upstream face of dam. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/16/Earthen+Dams+Earthen+dams+and+earthen+levees+are+the+most+ancient+type+of+embankments..jpg",
The transition filters prevent the migration of the core material into the pores of the previous zone material. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/31/Design+Criteria+for+Earth+Dams.jpg", flows continuously throughout the year), then in such a situation, the earth is more favourable for dam construction. On the other hand, if the thickness of the core equals or exceeds those limits. Porous drains remain enclosed in gravel filters. "@context": "http://schema.org", "name": "Erosion at Upstream Erosion of Upstream face",
{ To prevent cross currents from spillway, sidewalls of spillway should be constructed with adequate height and length. Horizontal Drainage FilterIt is provided at the base of the dam, starting from down stream end of the dam and extending backwards into the dam. A measure of how easily a fluid (e.g., water) can pass through a porous medium (e.g., soils) 2 Loose soil - easy to flow - high permeability. }, 35 { The downstream transition filter is useful during the steady seepage condition. A narrow U-shaped valley flowing between high rocky walls would suggest a concrete dam.
Non-Overflow dams \u2013 Many times Overflow dams and. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/18/Conditions+favouring+an+earth+dam.jpg",
Due to Frost Action. To prevent over-topping of dam, adequate freeboard should be provided. This is the most common type of a role fill dam in which a central impervious core is flank shells of previous material on the upstream and downstream of the dam. It also causes reduction in uplift pressure throughout the D/S side. "@type": "ImageObject", To prevent cross currents from spillway, sidewalls of spillway should be constructed with adequate height and length. If seepage pressure at the D/S end of the dam is still excessive, the horizontal filter drain may be continued even beyond the D/S toe of the dam. ", "width": "1024" A diaphragm type earth consists of a thin impervious core known as diaphragm, which is previous shells. "description": "Suitable foundation must be available. Silt and fine sand foundation: This type of foundation suggests the adoption of earth or very low gravity dam, up to height of 8 meter. It also causes drainage of foundation. "contentUrl": "https://slideplayer.com/slide/18121137/117/images/37/Seepage+Control+Through+the+Foundation.jpg", "contentUrl": "https://slideplayer.com/18121137/117/images/slide_42.jpg", The transition filters prevent the migration of the core material into the pores of the previous zone material. "name": "Hydraulic Failures of Earthfill Dams", ", A low-rolling plane country would suggest an earth fill dam. "@type": "ImageObject", Overflow dams - Spillways.
Seepage flow through the dam and foundation is so controlled that there is no danger of fine particles getting washed out from the downstream by the efflux of seepage. "@type": "ImageObject", "description": "The tail water present on the downstream side or cross-currents may come from spillway buckets may affects the downstream toe portion and erosion occurs. If the thickness of the diaphragm core at any elevation is less than 10 m or less than the height of the embankment above the corresponding elevation.
"name": "", They intercept the seepage through the foundation and control the outlet for seepage. The various types of foundations generally encountered are :-. The actuation forced and decreasing the resisting forces. { In recent days, four other types of dams have come into practice. The transition filters prevent the migration of the core material into the pores of the previous zone material. Chimney drain or filter, if correctly built, intercepts all the seepage from the dam regardless of the stratification in the dam. Important Earth Dams of the WorldGreen Mountain Dam on Colorado River in U.S.A Swift Dam in Washington in U.S.A Side flanks of Nagarjuna Sagar Dam in India Trinity Dam in California in U.S.A Maithan Dam in India (it is partly Earthen and partly Rockfill) If you wish to download it, please recommend it to your friends in any social system. Rock toe keeps seepage line well within the dam section. "width": "1024" Hence measures of seepage control are very important for the success of an earthen dam. In this situation, when sufficient spillway space is not available. ", Non-Overflow dams combined together to form a composite single structure. Hence for greater height, gravity dams are generally preferred. "@type": "ImageObject", "width": "1024" Factors affecting Selection of a Particular DamTopography Geology and Foundation Conditions Availability of Materials Spillway size and location Earthquake zone Height of Dam Other consideration "name": "Horizontal Drainage Filter", }, ENGINEERING GEOLOGICAL STUDIES for DAM CONSTRUCTION. Upstream slope is safe against rapid drawdown conditions while the downstream slope is safe against sloughing, Side slopes upstream and downstream are flat enough so that the shear stress-induced in the foundation is within the shear strength of the material comprising the foundation with a suitable factor of safety, Upstream slope is protected against erosion by wave action while the crest and downstream slope is protected against erosion due to wind and rain. This may be due to insufficient capacity of spillway or design without proper estimation of flood level or problem in lifting of spillway gates during flood times.
The amount of ater lost through seepage must be controlled so that it does not interfere with planned project functions, Transition filters are incorporated to satisfy the two essential conditions of filters, viz., to prevent choking of the filter by soil and have minimum of head loss in the filter, Dam as a whole is earthquake resistant. The dam site should be easily accessible, such that it can be economically connected to important towns.
Transition filters are incorporated to satisfy the two essential conditions of filters, viz., to prevent choking of the filter by soil and have minimum of head loss in the filter. Homogeneous Embankment Type. { "@context": "http://schema.org", "contentUrl": "https://slideplayer.com/slide/18121137/117/images/35/Horizontal+Drainage+Filter.jpg", }, 19 "description": "The Dutch breached their dikes during II world war to bedevil the invading Germans. To prevent this problem, stone pitching or rip rap should be provided on the downstream face of dam up to a depth of normal tail water level.
If possible, cut-off should extend upto the impervious strata lying below the ground level. }, 11 This filter controls seepage line and does not allow it to get exposed on D/S face of the dam. ", These are, Classification according to material used for dam construction, Diversion dams are also called weir or barrage, The detention dams to trap sediment- also called debris dams, Classification according to Hydraulic Designs, Non-Overflow dams Many times Overflow dams and. It includes life of dam, the width of roadway to be provided over the dam, overall cost of the construction and maintenance. It is provided at the base of the dam, starting from down stream end of the dam and extending backwards into the dam. Earthen dams are usually not provided for height more than 30 meter. It is used to prevent seepage through the foundation. }, 6 { ", Sometimes this may also cause slip of upstream slope. ", }, 40 The simplest type of an earthen embankment consists of asingle material and is homogeneous throughout. "@type": "ImageObject", The provision of U/S blanket is found economical and more effective when the depth of previous overburden is large and the provision of the cut-off wall is uneconomical.