Earthquake-induced deformation analyses of the Upper San Fernando Dam under the 1971 San Fernando Earthquake

A nonlinear effective stress finite element approach for dynamic analysis o f soil structure is described in the paper. Major features of this approach include the use of a third parameter in the two-parameter hyperbolic stres s-strain model, a modified expression for unloading-reloading modulus in th e Martin-Finn-Seed pore-water pressure model, and an additional pore-water pressure model based on cyclic shear stress. The additional pore-water pres sure model uses the equivalent number of uniform cyclic shear stresses for the assessment of pore-water pressure. Dynamic analyses were then conducted to simulate the seismically induced soil liquefaction and ground deformati on of the Upper San Fernando Dam under the 1971 San Fernando Earthquake. Th e analyses were conducted using the finite element computer program VERSAT. The computed zones of liquefaction and deformation are compared with the m easured response and with results obtained by others.