Mohammad Hassan Baziar - Research Assistant, Professor,repectively
Ricardo Dobry - Department of Civili Engineering, Rensselaer Polytechnic Instiute,Troy Ny۱۲۱۸۰
Mohammad F.Succearieh - Department of Civil Engineering, University of Alaska at Fairbank, Alaska, ۹۹۷۵

Earth dams, earth embankments, slopes and certain foundation soils are subjected to cyclic loading during earthquakes. Newmark' sliding block model can be used to estimate the permanent deformation of earth slopes due to earthquake loading. This paper investigates the applicability of the Newmark's method by performing several laboratory cyclic triaxial tests. This investigation determined under what condition this mechanism of failure can be observed in the laboratory by looking at the effect of frequency on the accumulated axial strain. Results obtained here suggests that the accumulated deformation is inversely proportional to the loading frequency in chained 'case only when the peak strength of the soil specimen is crossed by the combined cyclic and static stresses. However, results indicate that the accumulated axial strain is independent of loading frequency in undrained cases.