With time, moraine core soils of embankment dams may be damaged by internal erosion especially if the downstream filter is too coarse-grained. Suffusion is one of four types of internal erosion. During its process, the finest particles of the core soil are washed out by water, leaving only coarser particles in place. To prevent the internal erosion to leading to a breach by time, permeation grouting repair may be performed. In permeation grouting, the empty void system of the soil is filled with grout material, lowering its hydraulic conductivity. Knowledge of the needed grout pressure to grout to a certain depth will decrease the risk of unintentionally damaging the dam by heaving or hydraulic fracturing. 

In this paper, the hydraulic conductivity of a non-Newtonian fluid permeating a porous, coarse-grained material has been used to predict the grout pressures required for permeation grouting in embankment dams. In the laboratory, three types of coarse-grained materials were grouted with two types of low mobility grouts. The results indicate that hydraulic conductivity may be calculated from these tests and may be used to predetermine real grout pressures in an embankment dam. Grout velocities, viscosity and yield strength were found to be the most decisive factors for the results of the grout tests.