SPATIAL CORRELATED MULTI-POINT GROUND MOTION SIMULATION IN SEDIMENTARY VALLEY CONSIDERING SOIL NON-LINEARITY

A simulation method for spatial correlated multi-point ground motion in sedimentary valley considering soil nonlinear properties is proposed, which combines the reasonable spectral density function, the coherent function and the displacement amplitude ratio considering soil non-linearity and field scattering effect. Among them, the field nonlinear displacement amplitude ratio is calculated by the equivalent linearization method of coupled Finite Element-Indirect boundary element. The rationality and feasibility of the method are verified by the V-shaped semi-full valley model. The results show that, compared with the linear results, the peak value of ground motion acceleration decreases and the predominant period of response spectrum increases with the nonlinearity of the soil considered, and the magnitude of change is related to the thickness of the covering layer. The thicker the overburden, the greater the variation range, and the more significant the nonlinear effect. The research in this paper can provide important method and scientific support for seismic fortification of long-span engineering structures in valley site.