STRESS-STRAIN BEHAVIOR OF COMPACTED SANDY MATERIAL UNDER CYCLIC SIMPLE SHEAR

MASOUD MOHAJERI and IKUO TOWHATA

ABSTRACT: A conventional direct shear apparatus was modified to provide drained simple shear mode during cyclic loading. Several tests were performed in order to investigate the seismically induced deformation, stress-strain behavior and cyclic residual shear deformation of unsaturated and relatively dense sandy earth structures. This paper reports the effects of different parameters such as number of cycles, initial static shear stress, soil type, degree of compaction, consolidation time and stress, creep time and aging, amplitude of harmonic and irregular cyclic loading and loading rate on the cyclic stress-strain behavior and residual deformation accumulation of the samples. Based on the test results, concepts of Masing's rule are modified to model the stress-strain behavior of the material during the cyclic simple shear.

Key words: constitutive equation of soil, deformation, earthquake, repeated load, sandy soil,  simple shear test (ICG: E8)