Fifteen years have passed since I was working at a dam site super vising grouting work. That was not the first time that I had to car ry out engineering geological investigations for several similar projects, which always included testing programmes to find out the permeability of the rock, and often I was in charge of grouting work. It thus attracted my attention when this particular grouting programme did not run as intended: most of the grout holes took only very little grout It could not be the aim of the invested work simply to drill holes and fill them again without bringing about any...