Numerical investigation on the behavior of the gravity waterfront structures under earthquake loading

Lateral Spreading, which usually occurs as a consequence of liquefaction in gently sloped loose saturated sand layers, is known to be a major source of earthquake-induced damages to structures such as quay walls, bridge piers, pipelines, and highway/railways. Therefore evaluation of the liquefaction potential and using appropriate methods for prediction of the adverse consequences of lateral spreading is of great importance. In this study, numerical modeling has been used to study lateral spreading phenomenon behind rigid waterfront structures. Coupled dynamic field equations of the extended Biot's theory with u-P formulation are used for simulating the phenomenon. A fully coupled finite element code utilizing a critical state two-surface plasticity constitutive model has been applied and variation of permeability coefficient during liquefaction is taken into account. The developed code has been verified against the results of centrifuge experiment of VELACS No. 11. The numerical results are compared with the observed data consisting of seaward displacement of the wall, tilting and the generated pore water pressure in the soil. After validation, the influence of permeability and relative density of the soil on the residual deformation of the quay walls and on the generated pore water pressure are investigated. At the end, the effect of ground improvement on the seismic stability of the quay walls is investigated.