Abstract
A series of 1-g shaking table model tests were carried out to study the behavior of pile groups embedded in sloping ground subjected to lateral flow of liquefied soil. Two different configurations of pile groups: large (6×6 and 11×11) and small (3×3), were considered. The models were subjected to the liquefaction-induced large ground deformation to investigate the effect of several parameters on the response of pile groups and mechanism of lateral flow. These parameters comprise amplitude, frequency, and direction of input motion; density and slope of ground; and the thickness of non-liquefiable layer at the surface. The outcome of this parametric study reveals the importance of above mentioned factors which should be taken into account for analysis and design purposes. In addition, the results from the experiments clearly illustrate that in sloping ground configuration, both front (in upstream) and rear (in downstream) row piles receive greater lateral forces than middle row piles. This finding is attributed to the distribution of soil motion (displacement and velocity) of the liquefied soil in the model. As a result, installation of additional pile rows in front and behind an existing pile foundation can be considered as an effective retrofitting technique. Finally, soil-pile interaction was evaluated by running experiments with different pile spacings, and reliability of the JRA 2002 design manual in estimation of liquefaction-induced lateral force on piles is evaluated.
