Treatment of soft or weak foundation in a rockfill dam is of importance due to being susceptible to the large settlements, which may cause the dam body subjected to undesirable deformations and even, catastrophic failures. In this paper the stress- strain behavior of an under construction 58 m embankment dam in North-West of Iran, namely Gerdebin dam, and its soft and weak alluvial thick foundation has been assessed numerically. The effect of combination of consolidation and compaction grouting of the basement (as a remediation method) on the dam deformations and stress levels, is investigated. For this purpose, a finite difference based software (FLAC 2D ver. 4.00) has been used to evaluate the effects of the governing mechanical parameters on the dam body behavior. Results show that for certain values of the mechanical properties of the grouted zone, the dam body deformations reaches to the minimum level. The mechanical properties of the grouted zone materials are dependent on the grouting pattern. Hence, an optimized grouting pattern has been achieved for such a case problem. Such an optimized grouting pattern is already under the executing procedure at the dam site
