Peribonka Dam, Quebec, Canada

The project involved the use of se-
veral geotechnical construction techniques, including the installation of diaphragm and cut-off walls under the main dam body, to create a wa-
terproof barrier in highly permeable riverbed alluvia. The 25,000 m2 cut-
off wall was made of plastic concrete, and in one location was almost 116 m deep and 1.50 m wide. At the dam, the bedrock plunged to exceptional depths, forming a deep glacial gully. The geologic profile included the presence of granite, anorthosite, with strength sometimes in excess of
200 MPa, quasi vertical rock cliffs, rock overhangs, and the gully’s filling by some coarse alluvia, including boulders. For the cut-off wall portion, Bauer mobilized three cutters, including the CBS CBC 135, the biggest ever manufactured, with new features, and designed specifically for this project.