RIGID-BLOCK ANALYSIS

Rigid-block analysis is the analysis first developed by Newmark (1965), which treats the potential landslide block as a rigid mass (no internal deformation) that slides in a perfectly plastic manner on an inclined plane. Thus, the mass experiences no permanent displacement until the base acceleration exceeds the critical (yield) acceleration of the block; when the base acceleration exceeds the critical acceleration, the block begins to move downslope. Displacements are estimated by double-integrating the parts of an acceleration-time history that lie above the critical acceleration. Rigid-block analysis yields the best results for relatively thin landslides in stiff or brittle material having period ratios (T_s/T_m) less than about 0.2.