The Method Of Selecting The Damping Of The Soil Medium In A Two-dimensional Complex Field

With the rapid development of the modern cities,the loss caused by earthquake and disaster are growing exponentially,therefore,in order to maximally reduce the loss of earthquake disasters,we must do research in earthquake engineering.A large number of earthquake research show that the site condition has a significant effect on the soil seismic response.Theoretically,we should avoid these adverse terrain,however,because of the country's population,land resources are limited,it is difficult to completely avoid the disadvantage,so it is necessary for us to study the complex seismic response of the site study.Based on the theory of soil layer seismic response related research methods,with the related parameter model and earthquake records of Ashigara Valley test site,this article put forward a kind of input motion in complex field of seismic and selection method of the damping in the soil medium.in this article,the one-dimensional model and 2-dimensional seismic response analysis were used,and the results was compared with strong earthquake records.This paper get the following results:(1)For the surface earthquake records,one-dimensional soil column model is established based on the actual terrain,we can assume bedrock elastic inversion results as the input ground motion by finite element method in frequency domain,and with the theory of input(1/2 outcrop rock record),both difference are big.In some sense,nonlinear characteristic of the soil in test site of Ashigara Valley is obvious.(2)For the surface earthquake records,one-dimensional soil column model is established based on the actual terrain,with domestic and foreign general program of the equivalent linearized inversion bedrock results as input ground motion,and with the theory of input(1/2 outcrop rock record),there is a difference,but the effect is the ideal compared with elastic inversion,?There are many factors to affect the calculation results,such as the establishment of the model,The selection of dynamic parameters for the soil medium,calculation method,etc.(3)In this paper,a one-dimensional model was established and calculate in time domain,calculation model remain the same,dynamic parameters of the soil medium were selected final dynamic parameters after equivalent linearized inversion iteration.Calculated seismic response(acceleration time history curve and peak acceleration,effective time,the acceleration response spectrum)compared with the actual record,the results are consistent with it well.(4)In two-dimensional model calculation,three two-dimensional model is established in this paper,at the same time,the seismic input ground motion were selected for 1/2 outcrop rock record(theoretical),KS1 point equivalent linearization inversion bedrock motion,KS2 point equivalent linearization inversion bedrock motion at test site of Ashigara Valley.Soil medium respectively,the linear dynamic parameters of soil itself,the final soil dynamic parameters of two points after each equivalent linearization iteration.Through calculation,it is concluded that in this paper,the proposed two-dimensional linear model for the compared with two-dimensional linear model is more close to the actual record,and the damping ratio method is presented in this paper is correct and accurate.