Three‐Dimensional Seismic Analysis of La Villita Dam

Abstract

The three‐dimensional response of La Villita, an earth and rock‐fill dam in Mexico, during the earthquakes of November 15, 1975 and September 19, 1985, is investigated. A simplified numerical procedure is derived to represent upstream‐downstream, and coupled longitudinal‐vertical vibration. This procedure accounts for the dam alluvial foundation and the canyon geometric configuration. Soil behavior is modeled by a nonlinear hysteretic incremental‐plasticity model. Computations are performed using step‐by‐step time‐integration procedures. Accelerations and displacements are computed and compared to those actually observed. The computed (normal and shear) stress and strain histories at various locations within the dam are also shown. In general, the employed computational model is found to predict the magnitude of recorded accelerations with reasonable accuracy. The observed permanent deformations are found to exceed the computed values and are modeled by a simple sliding‐block formulation.