Abstract：In order to evaluate the seismic stability of foundation soil in Xiamen，earthquake reaction analysis for 4 typical sites were conducted using FEM and the way recommended by code for seismic design of buildings (GB50011–2001 of China) as well as shaking table test. The first site consists of a stratum of fill soil and two layers of sands as well as a layer of soft clay. The second site consists of only a stratum of fill soil with thickness of 10 meters. The third site is just a layer of soft clay with thickness of 26 meters. The fourth site is a middle-coarse sand containing some mud. The equivalent nonlinear constitutive model was adopted to describe the behaviors of various soils mentioned above. The pore water pressure model proposed by the authors was used to analyze the change of dynamic pore water pressure in the sand layers；The modulus softening method was applied to calculate the permanent deformation of the foundation soils. The sites were discreted by isoparameter element with 8 nodes. The dynamic reaction equations were solved with Wilson-θ method and frontal solution technique. Total of 20 cases were simulated numerically and analyzed including of three types of seismic waves (two kinds of natural earthquake waves of Xiamen and the earthquake wave of Songpan)，three peak accelerations of earthquake (i.e.，0.15，0.2，0.3 g)，4 intensity of static loads (i.e.，0，50，100，150 kPa). And the deformation fields，the pore water pressure fields，the seismic depression，the heave and the liquefaction grades for the four sites were obtained. The research results show that when strong earthquake takes place，the seismic depression of the fill foundation soil is not obvious and has small effect on the road of circle Amoy island. The seismic depression of the soft clay with large thickness is big；and failure patterns of the soft soil develops from local shear to general shear. The sand buried shallowly may be liquefaction. Above study results have an important consultation value to make aseismic decision of the foundation in Xiamen.
