In NTPC’s one of hydro project, treatments of foundation and abutments beneath earth-dam were done for safety of earth-dam. In most cases, excavation and filling in earth-dam proceeds in stages, with sufficient treatments to identify whether the geological and geotechnical requirements have been complied. Treatments for 'general foundation (GF)’ beneath the bulk area of dam is quite different from that of ‘cut-off foundation (CF)’ under the dam’s core. GF treatment is done to remove low strength and compressible materials to provide a foundation of adequate strength and compressibility. In most cases, GF will be of higher strength than dam and permeability will not be critical factor for this. Whereas, CF treatment is done to remove highly permeable and erodible material below GF level to provide a low permeable non-erodible foundation. Considering the complexity of rock formations with multiple joints, seams of fine materials, presence of large size voids, cavities, the foundation is also treated with grouting for which test blocks are selected at two locations for test grouting. After construction of the grout curtain, the interface is adequately treated with a primary purpose of sealing it to control hydraulic gradients and piping through the lower part of core, and with secondary purpose to reduce the quantity of seepage through dam core. In zones where the rock has been loosened by blasting, consolidation grouting of the dam foundation is undertaken to homogenize the rock mass and increase the strength and rigidity of rock mass. In case of cavities and large undulations, concreting and caulking are carried out. Due to the unpredictability of some parts of above works as the volume of the treatment depends on the actual quality of the ground as the excavation works go, it is learnt that there is need to plan properly with reasonable time and cost provisions.