Response of Pile Groups Against Seismically Induced Lateral Flow in Centrifuge Model Tests

The response of pile groups against seismically induced lateral soil spreading is explored in centrifuge model tests. The influence of number of piles and pile spacing on the total lateral force on piles is especially examined. The silt saturated with water was used to produce geotechnical models in the laminar shear box. The model piles were installed in 1-layer and 2-layer soil models to produce various patterns of pile groups, with different number of piles and pile spacing. In one test series, the pile groups were installed in the direction perpendicular to lateral spreading, while in another test series, the pile groups were installed in the direction parallel to lateral spreading. The instrumented models were then seismically excited at elevated centrifuge gravity. The group effects of closely spaced piles on the total lateral force induced during lateral spreading are evaluated with respect to the number of piles and pile spacing, with a help of a simple theoretical consideration.