Effect of Soil Material Models on SPH Simulations for Soil-Structure Interaction

Currently, civil engineering design practice uses liner elastic soil properties for many soil- structure interaction problems. However, this approach falls short for problems in which the structure and soil undergo large deformations. With the availability of the high-performance computing (HPC) cluster at the United States Department of Transportation’s Transportation Research and Analysis Computing Center [1], transportation researchers can investigate complex soil-structure interaction problems. One of these problems is the stability of bridge piers during flash floods [2]. For certain riverbed soils, the high-velocity water washes away the soil covering the bridge piers, and this scour action can eventually expose the bottom of the pier and footing. In order to simulate this complex behavior, it is necessary to model the response of the reinforced concrete column – including concrete material failure – and the nonlinear soil behavior. This paper addresses some of the issues related to soil modeling. The following four material models were studied: (1) MAT005, Soil and Crushable Foam; (2) MAT010, Elastic Plastic Hydro; (3) MAT025, Geological Cap; and (4) MAT079, Hysteretic Soil. The first step in modeling the soil is to choose an appropriate model. The second step is to obtain the material parameters required by the specific model chosen. Some basic models require only a few parameters while the more complex models require many more. For site specific analysis, soil testing is required and then skilled analysts extract the needed parameters. The parameters obtained from soil test are given for the above four soil models. The hydrostatic compression response predicted by each model is compared to experimental data. The MAT005 and MAT025 materials were used in a three-dimensional SPH simulation of a rigid platen being pushed into sand.