Analysis of Influence Characteristics of Site Ground Motion in Ya'an Area,Sichuan

In order to analyze the vibration characteristics caused by the site structure in the Ya'an area, the actual test boreholes in the major safety assessment projects in the area were selected for site seismic response analysis, The equivalent linearization method was used to carry out the site response calculation with the NGA strong earthquake records as the input. On the basis of a comprehensive analysis of the seismic characteristics of the site in this area, the peak velocity was used as the parameter index to study the magnification effect of the peak velocity caused by the site conditions. The main research results are as follows: The predominant period of the site in the Ya'an area is around the range of 0.2 s, and the building structure damage will be relatively severe if the natural vibration period is in this range; With the increase of the peak acceleration of the bedrock, the peak velocity shows an increasing trend, However, the changes in the peak velocity and the peak acceleration are not all consistent, so the variation laws of various ground motion parameters should be considered when analyzing the site effect.;The peak velocity magnification factor is between 1 and 1.5 under different seismic inputs; The site coefficient k_v generally decreases with the increase of the equivalent shear wave velocity and soft soil filed is more likely to cause amplification of the peak velocity, especially in Lushan earthquake.