Abstract：Considering structure-ground dynamic interaction is consistently required in the seismic
specifications of nuclear power station in different countries, and the reasonable simulation of
dynamic characteristics of non-homogeneous ground is particularly one of those focuses. Based on
the idea of applying the high artificial damping and then gradually extracting its influence
through shifting the frequency axis, Damping Solvent Stepwise Extraction Method (DSSEM) is
proposed, which can reduce the undesirable mutual restriction between high artificial damping and
site size as much as possible. By coupling the upper nuclear island (NI) substructure, the seismic
response analysis model for NI structures under complicated non-homogeneous site conditions can be
established within the finite element framework. Furthermore, the corresponding implementation
formula is provided for the convenience of development in the general finite element software. The
dynamic analysis of massless square plate resting on homogeneous half-space ground and non-
homogeneous layered ground were carried out, respectively, to verify the proposed computational
model. The influence of local non-homogeneity in ground on the response of the NI structure was
then discussed. The computational results indicate that the measured underground xenolith may have
a slight influence on the seismic response of NI structure, and the proposed model appears to
possess good accuracy and efficiency, so that it is applicable to non-homogeneous ground with
complicated geometry and structure.
