Nick Taylor Oct 9, 2016:

Remembering the many many civil construction terms I have translated, 9 times out of 10 "barragem de contenção" is cofferdam. See below:
http://drsksingh.tripod.com/bridge2.htm
In this case made from embankments rather than caissons.

airmailrpl Oct 9, 2016:

alternative: barragem de contenção de taludes => barragem de contenção feito (construido) de taludes

Mario Freitas Oct 9, 2016:

Ambiguity There is an issue here with the interpretation of this expression. When I posted my suggestion, I thought of a contingency structure for an event of slope liquefaction. In that case, I would call it an abutment (wall).
However, looking at the question again, I noted that perhaps the author meant a "containment dam composed of slopes", in which case, it's actually a dam, not an abutment.
It will depend on the context, really.