The Effect of Soil Nonlinearity on Dynamic Structure-Soil-Structure Interaction

The effect of soil nonlinearity on dynamic structure-soil-structure interaction (SSSI) is investigated using a 2D model of two sup-structures supported by rigid foundations embedded in soil layers over elastic bedrock by finite element-indirect boundary element (FE-IBE) coupled method. In the model, the near-field soil and far-field soil, which both can experience nonlinear deformations, are modeled by finite element and indirect boundary element method, respectively. In the parametric analysis, the contribution of linear SSSI and soil nonlinearity, as well as the soil- structure interaction (SSI) of a single structure and structure-structure across interaction , to the combined SSSI effect are assessed. It is shown that the soil nonlinearity reduce shearing relative displacement amplitudes significantly, while it enlarges foundation rotation significantly; both linear SSSI and soil nonlinearity contribute significantly to the combined SSSI, and basically the proportion of linear SSSI is larger; if the adjacent structure is much heavier or the excitation is larger, the influence of soil nonlinearity is larger. In addition, the SSI considering soil nonlinearity accounts for much larger proportion than the across interaction; if the adjacent structure is much heavier, the across interaction may enlarge foundation rotation obviously. In conclusion, SSSI with soil nonlinearity may be significantly different from linear SSSI or SSI with soil nonlinearity.