Additional insight into soil behavi

Additional insight into soil behavior throughout testing was provided from the displacement of particles near the rotating wall-soil interface at various depths. String potentiometers 13, 2, and 18 were attached to particles placed at or near the center of the container at depths of 216, 394, and 584 mm, respectively, and approximately 25 mm from the stiffened wall. The movement of these particles is plotted in Figure 3 with movements away from the wall in the positive direction. It can be readily observed that, as expected, displacements are comparatively greater towards the surface. Furthermore, not all displacements are recovered when the wall moves away from the soil. This is most probably a result of nearby soil particles at a higher elevation moving into place between the instrumented particles and rotating wall. This movement was significant by the end of the test and easily observed with the human eye. Movement of more particles into the space opened by the wall rotating away from the retained soil is consistent with theories explaining the increase in lateral earth pressure with cycles.