Three-Dimensional Dynamic Analysis on Soil-Structure Applying Mixed Linear-Nonlinear Substructure Method

To increase the computation efficiency of the three-dimensional nonlinear dynamic analysis of soil-structure, the liner-nonlinear mixed constrained mode synthesis method was put forward according to the characteristic that the structure owns local plastic region, which is appropriate for both nonlinear substructure and multi linear substructures with boundary coupling. Divided the whole system into linear substructure and nonlinear substructure, this method reduced the freedom degree of linear substructure according to the potential energy criterion and finally synthesized them with the nonlinear substructure, thus obtaining the dynamic response of nonlinear system. The accuracy and effectiveness of this method were proved by further applying this method in the three-dimensional dynamic analysis example of soil-high building interaction system to carry out dynamic time-history analyses under the effect of multi-groups earthquake incentives respectively for two different boundary conditions of soil mass. Finally, several groups of numerical experimentations were conducted based on the various different values of nonlinear soil mass region, and the result indicated that as far as the example of this paper was concerned, it can obtain satisfiable computation result when the range of nonlinear soil mass region was 3 times of the horizontal size of upper structure, which further demonstrated the effectiveness of the method proposed in this paper.