A practice oriented pore-pressure generation model

A simple, practice oriented pore-pressure generation model is described. The model consists of a linear elastic/perfectly plastic Mohr-Coulomb constitutive model coupled with an empirical pore-pressure generation scheme. Pore pressure is generated in response to shear stress cycles following the cyclic-stress approach of H.B. Seed and I.M. Idriss. However, unlike the standard cyclic-stress approach, pore pressure is generated incrementally during shaking. The model is illustrated through two analyses of the Lower San Fernando Dam. The first analysis, for the 1971 San Fernando earthquake, illustrates a case in which a large liquefaction induced slide occurs. The second analysis, for the rebuilt Lower San Fernando Dam during the 1994 Northridge earthquake, illustrates a case in which smaller shaking-induced permanent displacements occur.