Design and Analysis of Headwork on A Challenging Foundation Condition (The Case of Kuraz Project on Omo River)
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Date
2014-06
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Addis Ababa University
Abstract
The foundation geology at a diversion site often dictates the type of dam suitable for that site. The strength, thickness, and inclination of strata; permeability; fracturing; and faulting are all important considerations in selecting the diversion structure type. Occasionally, like the problems in Kuraz project the foundation formation show clear distinction in vertical level of appearance of a given material, two clear distinct faults within its longitudinal span axis, the structure‟s immediate foundation is resting on alternating strong and weak formations with different bearing capacity exerting differential pressure creating overstress in the structure will create differential settlement and the existence of the sandy silt formation at different levels along the longitudinal axis creates a liquefaction prone soil during an Earth quake. The major objective of this project is to study the Design and analysis of a diversion head work or small dam on a challenging foundation condition especially solving the problem on Kuraz Project on Omo River by providing technically, economically and functionally plausible alternative solutions.
In this research the following have been accomplished: important data were collected from existing documents, laboratory test results and other secondary data sources of the project and the final computation and the analysis is presented using Geo-Studio soft wares. Thus, the scope of the research will be limited to identifying or selection of appropriate headwork typology, hydraulic design and analysis of a foundation for the structures on the existing complex geology requiring very careful approach. In additions the research emphasizes to demonstrate theories, procedures and techniques through practical applications.
For this particular challenging foundation conditions, it was proposed three different possible alternatives. which wereOn the rock foundation (right side) concrete weir and on the island and left side of the structure earth fill Dam, on the rock foundation (right side) concrete structure and on the island and left side of the structure earth-rock fill structure and Entire weir structure which is proposed by WWDSE.Hence after design of all the three alternatives of the structures and analysis using Geo-Studio software the results indicate that for the embankment part of the structures, the first alternative was selected as the most economical, functional and practical plausible alternative.
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Particular challenging foundation conditions