STABILITY OF MOTIONS OF TRANSLATIONAL LANDSLIDES

This paper considers the stability of motions of translational landslides in which the frictional resistance has been assumed to depend on the velocity of sliding. There is a growing body of evidence that suggests many soils exhibit some strength-velocity dependence, and both negative and positive sloping strength-velocity relationships have been observed. A simple stability analysis shows that stable sliding can only occur when the strength-velocity slope is positive. An example problem is considered to illustrate the variety of possible motions, both stable and unstable, that may occur due to changes in piezometric elevation within the slope, or due to changes in external loading. A particular strength-velocity relationship is proposed for purposes of illustration. It exhibits both velocity weakening and velocity strengthening for different ranges of slip velocity. The paper concludes with a discussion of effects of nonrigid motions of the sliding mass. More complex behavior is then possible but results suggest overall stability will be unchanged from the simpler single rigid-block analysis commonly used.