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14 Cards in this Set
- Front
- Back
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What are some components of a dam that geology may impact?
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Excess seepage, and groundwater inflow into excavation tunnels
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What is a cofferdam?
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A TEMPORARY barrier that redirects water into a diversion tunnel, preventing the river from flowing through dam construction sites.
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What is an Abutment?
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The sides of the valley on which the structure of the dam rests.
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What is the dam Foundation?
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Floors of the valley on which the structure of the dam sits.
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What is the Diversion tunnel?
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Tunnels constructed for diverting water before the construction of the dam, helps to keep the river bed dry.
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What does the type and size of a dam depend on?
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-need for water
-water available -topography -geology of the site -construction materials available |
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What are the 3 types of dams?
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Concrete, Earth, and Hybrids.
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What are some dam design issues?
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-Dam Stability: foundation/abutment issues, overturning and sliding
-spillways construction dissipates energy and prevents overturning -Dam leakage: erosion of dam material/foundation/abutment -landslide generated waves |
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What are the 3 main types of concrete dams?
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Gravity, Buttress and Arch
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Describe a Gravity dam
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Uses its BULK WEIGHT and LOW CENTER OF GRAVITY to hold back water, can be built across LONG DISTANCES over FLAT terrain, NON-mountainous regions where foundation is competent and stable.
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Describe a Buttress dam.
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Uses MULTIPLE COLUMNS to support dam, relatively THIN structure, uses HALF as much concrete as Gravity dams, can be used a foundation materials that are a little bit weaker.
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Describe an Arch dam.
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Utilizes the STRENGTH OF AN ARCH, displaces the load of water behind abutments. LESS materials, but MORE EXPENSIVE due to the amount of EXPERTISE NEEDED, built where walls of canyon are CRAZY STABLE, and IMPERVIOUS TO SEEPAGE.
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What are some principle features of dam foundation materials?
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Adequate STRENGTH and IMPRESSIONABILITY, IMPERMEABLE enough to prevent excess seepage.
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Describe an Earth dam.
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Built with clay/sand/gravel, trapezoid shape, "embankment dams". Consists of core of impermeable material (clay), supported by permeable shoulders of earth and rock fill.
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