Modeling of concrete, soil, and interfaces

The ability to predict the response of structures subjected to large, abrupt bursts of energy depends on a number of factors. These include load definition, the characteristics of the geological material in which the structure is embedded, the mechanism by which forces are transferred from the geological material to the structure, and the characteristics of the structure. The basic objective of the research project discussed here is to provide an improved understanding of the response of common geological and structural materials and of structure-media (concrete-soil) interfaces (SMI), to abrupt loading. For this purpose, engineering constitutive models have been developed, and appropriate experimental data are being used to validate the models. An improved relation for predicting the limit surface of concrete is given. The need for new devices and measurement techniques for rate effects in concrete and the response of unsaturated clay and salt is discussed. Preliminary data from existing experimental equipment are shown. The implications of strain softening are displayed with the use of a model problem. Proposed work includes the use of a strain-softening model to represent interfaces, the extension of the viscoplastic model to represent anisotropic media, and the determination of rate effects in concrete for one and two-dimensional experimental specimens.