Practical Criteria for Determining the Tolerable Permeability

The consequence of the rock-type-specific groutability is that the original permeability can be reduced only to a certain specific degree when normal cement grouting is applied. The remaining permeability can be larger than the “tolerable permeability”, which is the measure of conductivity which is still acceptable regarding water loss and stability to erosion. The degree of tolerable permeability is specific to every rock type and the situation of the individual projects, i.e. it can be different from case to case; it can also differ greatly from the previously mentioned groutable permeability, being higher or lower. The results of this study have concluded that the tolerable permeability should not be set according to the criterion of 1 Lugeon.