To research seismic response characteristics of sites with deep and soft soils

three typical sites from Nanjing?Yancheng and Shanghai are selected and analysed respectively in the paper. At first

making use of model GZZ-1 free vibration column test system

the authors do the experiment on the undisturbed soil samples from the three sites

and the curves of dynamic shear modulus ratio G/G

max

and damping ratio λ versus dynamic strain amplitude γ for all sorts of soils are attained. Secondly

utilizing SHAKE91 program

the seismic response characteristic of three sites is obtained. In the paper

Taft earthquake wave?El Centro earthquake wave and Northridge earthquake wave are regarded as inp

ut waves

and their peak acceleration is adjusted to 0.35 m/s

2

?0.70 m/s

2

and 0.98 m/s

2

. So the paper analyses site seismic effect of 27 cases. Through the numerical analysis of all sites

the following can be concluded: the factor as site condition and the characteristic of input wave have an obvious impact on ground surface acceleration amplifing effect of soil strata

the less the ground surface acceleration amplification factor

the larger the peak value of input acceleration time-history is

but this regulation is not obvious for inside soil strata; the ground surface acceleration amplification factor will increase quickly when there is soft strata at the ground surface; the ground surface acceleration amplification factor at soft mucky soil is relatively bigger than other soil strata

and this strata is easily destructed under strong motion; shear strain of the interbedded strata will be bigger because of its particular layer construction.