SHEAR STRAIN DISTRIBUTION IN SOIL AROUND GEOGRID DURING THE UNLOADING-RELOADING PULLOUT TEST

Abstract

The soil-geogrid interaction process was analyzed by the Particle Image Velocimetry furthermore spatial discretization scheme in finite element method to understand about the dilatancy mechanism and shear strain distribution during unloading-reloading process. In this test the geogrid was pushed back and forth at three stages of pullout test: before peak, at peak and at residual part to simulate the seismic activities. Results showed that the shear strain concentrated in front of transverse ribs and upper apart of pullout box. The dilative behavior appears in front of transverse ribs and contractive behavior exits at behind of these bars. The alternative soil dilatancy-contraction distribution in between the two transverse ribs can be seen throughout the length of geogrid.