Development of an Improved Numerical Model for Concrete-to-Soil Interfaces in Soil-Structure Interaction Analyses. Report 1 Preliminary Study

Abstract

Abstract : Soil-Structure Interaction (SSI) analyses have proven to be powerful tools for use in analyzing, designing, and monitoring geotechnical structures. SSI analyses are particularly useful in problems of complex geometry and loading conditions such as lock walls. Several SSI analyses of Corps of Engineers lock walls have shown that the behavior of the soil-structure interface has a significant influence on the magnitudes of the loads acting against a lock wall. They have also illustrated that the pre- and post-construction field stress paths followed by interface elements often involve simultaneous changes in normal and shear stresses, as well as shear stress reversals. The hyperbolic formulation for interfaces, used commonly in SSI analyses, models interface behavior in the primary loading stage very closely. However, it has not been extended to accurately model simultaneous changes in shear and normal stresses, reduction of shear stress, reversals in the direction of shear, or unload-reload cycles at the interface. The purpose of this research is to develop an interface model capable of giving accurate predictions of the interface response under field loading conditions. In order to develop the necessary test data, the Large Displacement Shear Box (LDSB) at Virginia Polytechnic Institute and State University, Blacksburg, VA, was modified to permit soil-to-concrete interface testing. A. concrete specimen for interface testing was prepared with a surface texture similar to that of concrete retaining walls in service. A number of tests were performed on the interface between this concrete specimen and a uniform dense sand: initial loading, shear reversals, staged shear, and unloading-reloading of the interface. This research is being conducted in two phases. This report presents the results of the testing performed for the Phase I research.