Dynamic Analysis of Concrete Faced Rock Fill Dams (A Case Study on Lower Awash Multi-Purpose Dam Project)
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Date
2017-06
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Addis Ababa University
Abstract
This research work presents a Dynamic Analysis of Concrete Faced Rock Fill Dam located in a high seismic zone in Afar national regional state in the Lower Awash Sub-basin, Ethiopia. The Analysis considered dam configuration of 48m high.The concrete Face Slab will be lined along the dam upstream slope face and extend to top foundation level.
The Dynamic Analyses of Concrete Faced Rock Fill Dam is investigated through numerical analyses of Geo-studio 2007 software packages using both Limit equilibrium and Finite element method.
The Dam was originally designed with Zoned Earth-Rock Fill Dam with Central Clay Core.This research work on Concrete Faced Rock Fill Dam was aimedto provide a feasible dam design alternative under clay core material constraint for zoned earth-rock fill dam with central clay core under seismic load of maximum credible earthquake (MCE) and safety evaluation earthquake (SEE).
The horizontal accelerations generated under the influence of a set of base rock motions are computed for reservoir levels at normal pool level and ground motion intensities. The analyses of Concrete Faced Rock Fill Dam was conducted using three different earthquake ( Elcentro, Hachinohe and Kobe) records of similar modified maximum acceleration and duration as base excitation are compared. Applying these seismic shocks,the horizontal and crest settlements are 140mm and 150mm respectively, which means the induced deformations, do not require additional extension of dam or cumber height.
The upstream slope of the dam is stable in all the three earthquake loading conditions against sliding, however, downstream slopes showed a little lower factor of safety than minimum recommended factor of safety against sliding.The thick alluvium foundation of the dam is completely liquefied even for Kobe earthquakes records of short duration for both MCE and SEE, which indicates a potential failure surface if the dam is founded on the thick loose alluvial deposit.
Keywords:Maximum Credible Earthquake, Design Base Earthquake, Finite Element Method, Limit Equilibrium Method, Permanent Deformation and Liquefaction.
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Keywords
Maximum Credible Earthquake, Design Base Earthquake, Finite Element Method, Limit Equilibrium Method, Permanent Deformation and Liquefaction