Behavior of Pile Group in Liquefied Soil Deposits Under Earthquake Loadings: Fid-Bau Portal

Behavior of Pile Group in Liquefied Soil Deposits Under Earthquake Loadings

Basavanagowda, G. M. / Gowthami, P. / Dinesh, S. V. / Govindaraju, L. / Balareddy, S. Muttana

Pile foundation is extensively used for the support of bridges and other structures to safely transfer structural loads to the bearing ground through the pile with skin friction and end bearing mechanism and to avoid lateral movement and excessive settlement. Lateral loads come from a variety of sources, including earthquake, ship impact, waves, and wind. Design of foundation in seismic regions typically if the soil strata are likely to get liquefied is a challenging task. Piles have failed due to large bending moments at the interface of liquefiable non-liquefiable layers. The behavior of single pile and group of piles in liquefied deposit is a complex issue and uncertainty exists regarding quantification of pile displacement, bending moment, shear force, and other parameters. In the current study, the numerical simulations were carried out using finite difference software FLAC3D. The soil model has three layers, slightly cemented sand at the top and bottom, Nevada sand at the middle with water table at the ground level. The Mohr-Coulomb model was assigned to the soil grid as the constitutive model, and the pile was modeled as a structural element. Analysis was carried out for the pile and pile group having floating pile head condition. The simulation was carried out by considering Cyclic, Bhuj, and El Centro acceleration time history as input ground motions. The pile analysis results were represented in terms of displacement, bending moment, shear force, and pore pressure ratio along the pile length. The numerical analysis results were compared with the results in the literature for validation. It was observed that the pile displacement is maximum at the pile top, and maximum bending moment occurs at or near the interface of liquefiable and non-liquefiable layers. The pore pressure ratio indicates liquefaction of Nevada sand. The pile displacement and bending moment were dependent on peak ground acceleration, duration of strong ground motion.