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An area at the surface of approximately 300.000 m2 has been sliding for a long time in a gently sloping mountain side in the community of Stranda in West Norway. The thickness of the sliding rock mass is estimated to range from 15 to 45 m, with an average of 20 m. The sliding area, is divided in to two parts with respect to the rate of sliding, the western part with an approximate volume of 1.4 mill. m3 of rock and the more stable and gently sloping eastern part with an estimated volume of 4.5 mill. m3. The 2D-discontinuum numerical code UDEC-BB (Barton-Bandis joint model) has been used for modelling the kernes landslide. Two different models of the kernes landslide were produced. The first model was run dry, not taking into account the pore water found in the field. This model was run to equilibrium without any signs of instability. The second model was run with sequential increase of pore water pressure on its boundary, and a landslide was initiated in the lower part of the slope as the water level rose. The numerical results are in good agreement with the conclusions drawn from an earlier NGI report where it was stated that the variation of pore pressure on the sliding plane, is the main reason for the continuous movement of the rock slope.
The development of discontinuum modelling procedures such as the distinct element method (DEM) represents an important step in the modelling and understanding of the mechanical deformation behaviour of jointed rock masses. This type of code has been specifically developed for blocky structures in which the mechanical discontinuities play an important role in the overall deformation behaviour, or where joint conductivity (leakage) is important. The method is based upon an explicit time- marching procedure that allows large displacements and rotations to occur and in general non-linear constitutive behaviour for both the rock matrix and the joints.
A structural geological description is given in the NGI report (Grimstad, E, 1989). An area at the surface of approximately 300.000 m2 has been sliding for a long time in a gently sloping mountain side in the Sunnylvsfjord near the community of Stranda in West Norway. The thickness of the sliding rock mass is estimated to range from 15 to 45 m, with an average of 20 m. The sliding area, which is situated between 900 and 525 m. a.s.l., is divided in to two parts with respect to the rate of sliding. The western part with an approximate volume of 1.4 mill, m3 of rock has moved approximately 25 m downhill. The more stable and gently sloping eastern part with an estimated volume of 4.5 mill, m3 has moved 2 m in the western edge. This part seems to have rotated around an axis at it's eastern edge, giving a linear movement of 2 m on the western side.
