| Shallow slopes in clayey colluvial covers are often involved in progressive
downhill motion with discontinuous rate of movements, depending on
fluctuations in pore-water pressure.
In geotechnical engineering research on natural slopes, the main efforts
have been concentrated on stability analysis, always with a rigid perfectly
plastic body assumption. In case of slow slope movements, however, the
notion of stability losses its sense, so the main question is not to
evaluate a stability factor, but to model a velocity field and to define the
kinematic and dynamic features of the movement (mobility analysis).
Many authors, in their researches, deal with slow slope movements and for
the complexity of the problem and the great number of parameters involved
they agree about applying numerical techniques (FEM, FDM) and advanced
material modelling (elastoviscoplasticity) and suggest to calibrate the
involved parameters values with the help of ''back analyses'' of existing
case histories.
In this paper a mathematical model predicting the landslide body viscous
deformations, is presented. The model has been implemented in a computer FDM
code, and has been tested on some well known case histories. Here it is
applied to the case of a landslide occurred at Gagliano Castelferrato
(Sicily – Italy), where a great number of field measurements was available. |