POST-CYCLIC BEHAVIOR OF GRANULAR SOIL- STRUCTURE INTERFACE DIRECT SHEAR TESTS

Abstract

The purpose of this paper is to present one of the most important phases of a series of cyclic
direct shear tests on granular soil and rough material interface under constant normal stiffness (CNS)
condition. These cyclic interface tests were performed in order to simulate the situation along the pile shaft
subjected to a large number of cycles due to environmental or anthropic loadings. This post-cyclic phase can
be performed by one single large cycle after the cyclic phase in order to characterize the change of interface
resistance. The principal characteristic of interface subjected to cyclic loading is the progressive contraction.
This phenomenon leads to the degradation in normal stress acting on the pile shaft and consequently the
shear resistance decreases. The influence of relative density of granular soil, initial normal stress, level of
stress ratio, cyclic amplitude and imposed normal stiffness on the post-cyclic responses is discussed.