EARTHQUAKE INDUCED LIQUEFACTION ANALYSIS OF TENDAHO EARTH-FILL DAM

Abstract

This paper presents earthquake induced liquefaction analysis of Tendaho earth-fill dam, which is part of Tendaho Dam and Irrigation Project; the largest irrigation project in Ethiopia to date. The dam is located in the most seismic part of Ethiopia and was originally designed to be founded on potentially liquefiable alluvium foundation. The analysis presented in this paper is the first of its kind in the country and has resulted in significant changes in the original design of Tendaho dam. Geological formations of the dam site, behavior of different materials used for building the dam, and site specific earthquake have been incorporated in the analysis. The dynamic analysis results revealed that the loosely deposited alluvium foundation would completely liquefy under earthquake loading, endangering the stability of the dam. Hence, following the recommendations made in this study, the 6 to 10 m thick alluvium foundation under the dam seat has been completely removed prior to placement of the dam. Construction of the dam has been completed recently.