Numerical study of stability for the Oppstadhornet rock-slope failure

The Oppstadhornet rock-slope failure in Møre & Romsdal County is one of numerous failures in western Norway. The rock slope is of special interest for two reasons: (i) It involves large rock volumes (approximately 20 mill. m3) that may cause a major tsunami, and (ii) its location near the Molde city (17 km) enhances the risk. Detailed geological mapping and measurement of geological parameters in field and labora-tory form the basis for the numerical stability analyses. The shear strength parameters measured are in accor-dance with Barton-Bandis shear strength criteria. A representative cross section is established along the wedge failure line and implemented into UDEC (Universal Distinct Element Code), a discontinuous two-dimensional numerical analysis programme. Analysing today’s slope stability is of main interest, but a back analysis is also performed to calibrate the input parameters and to recreate the sliding to today’s situation.