Estimating undrained cyclic behavior of compacted mixed clayey soils by statistical tools

Cyclic loading-induced pore water pressure and degradation in the stiffness and strength of saturated soils are most important in dynamic stability analyses of soil structures, because they highly influence the behavior of soils. Conducting laboratory tests for the study behavior of soils is time- consuming, requires huge effort, and is usually expensive. Thereby, the prediction of soil behavior using analytical models can be utilized in the feasibility studies of projects, early decisions in the field, parametric analytical evaluations, etc. Therefore, some efforts have been made to model the excess pore water pressure and degradation characteristics of sandy and clayey soils due to cyclic loading; however, mixed clayey soils have not been examined in detail. This article offer regression analysis- based models to determine the cyclic loading-induced pore water pressure and degradation index of mixed clayey soils using laboratory tests data. The major parameters of the models are the number of loading cycles, cyclic strain amplitude, granular material content, and effective confining pressure. To establish functional relationships between variables, some linear and nonlinear regression tools are used. Residual analyses of the models illustrate that they are superior in establishing meaningful correlations and can be employed effectively, in practice, in the range of parameters used in conducting laboratory tests.