ABSTRACT
Located on the Our River on Luxembourg’s eastern border with Germany, the Vianden pumped storage power plant was commissioned in 1964. The plant has a two-section upper basin, which was built on the summit plateau of the Nikolausberg mountain. The ring dam enclosing the upper basin is designed as a rockfill dam with an asphalt surface sealing. In the context of a routine safety review of the ring dam, in 2021 large-scale triaxial shear tests were carried out on the existing dam fill material. The aim of the tests was to verify the shear parameters adopted for the design considering an operating period of almost 60 years with regard to the stability calculations to be carried out. The paper describes the tests carried out and presents the results in the specific setting of the investigation program, which was performed as a basis for the safety review. The test results are also put into perspective of the frequently used approach for rockfill dams from Leps (1970) with a stress-dependent friction angle for different material qualities.
