Investigation Trenches

Investigation trenches help produce information of the surface of bedrock in Olkiluoto. A total of 16 investigation trenches have been excavated.

The investigation trenches are done by removing all loose soil from on top of the rock and by cleaning the rock surface. The rock surface is studied for the presence of different types of rock, fractures, cleavage, folding and displacements. After examination, the investigation trench is filled in and landscaped. The investigation trenches may be several hundred metres long and almost ten metres deep.

Often, investigation trenches are made in conjunction with drill holes so that the structures found by drilling can be seen on the rock surface. This information can be later utilised for preparing a geological model of the bedrock.