Compaction Control of Soil-Rock Mixtures at Odelouca Dam

Abstract

Recently, soil-rock mixtures are being used in the construction of embankment dam shoulders. This situation represents new challenges to compaction techniques and their control as well as to the determination of the characteristics of the fill that results from the compaction method, as those characteristics suffer important changes according to the relative percentage of the existing fractions. For the execution control of the soil-rock mixtures from the Odelouca dam borrow areas, presently being constructed at South of Portugal, a series of vibratory compaction tests and rammer compaction tests were performed to estimate reference values for the maximum dry density and optimum water content of these materials. Odelouca dam is a zoned earth fill dam, with 76 m height with clayey soil at the core and weathered schist with a significant fraction of oversized particles at the slopes. This paper presents the results of these tests. Following the methodology, developed in 1994, by Torrey & Donaghe, a set of correction equations of the Proctor reference values (obtained on a partial finer fraction passing in the ¾” sieve) for the extrapolation of the control properties of integral material for schistose material is presented. Additionally a new methodology based in different parameters is proposed.