Behaviour of Saturated Sand Models under Principal Stress Axes Rotation in Shake Table Tests

One dimensional shake table tests were performed on saturated loose or medium dense Toyoura sand models, in order to study the response of level grounds during earthquakes and the nature of generated excess pore water pressure. 12 virgin models which prepared under identical condition, were subjected to cyclic and three different irregular shear stress patterns. It is shown that there is correlation between excess pore pressure ratio and developed shear strain, independent from applied shear stress histories and density of the models. Also, the relations of accumulated shear work as well as normalized shear work, per unit volume, are considered with generated pore pressure. According to the results of this study, in the first part of the experiments that undrained condition can be assumed, mentioned parameters correlate with excess pore pressure. This relation is independent from stress path for shear work and from stress path and confining pressure for normalized shear work