Ground pulsation tests and analysis on seismic response of typical ground fissure sites in Xi’an

The extensive development of ground fissures in Xi’an severely restricts the construction and planning of the city. The existence of ground fissures makes the building sites show different seismic response characteristics under earthquakes. Therefore, it is of great significance to study the seismic response characteristics of ground fissure sites in Xi’an for the seismic fortification of ground fissure sites. Taking typical ground fissures in Xi’an as the research object, the characteristics of ground fissures in Xi’an were obtained on the basis of field investigation; the predominant frequency of the ground fissure sites, which is an important parameter reflecting the dynamic characteristics of the formation, is obtained. The seismic fortification distance of the dynamic response law of the site is obtained through the Fourier spectrum analysis of different measuring points. The research shows that the predominant frequency of the ground fissure site in Xi’an is in the range of 2.79−3.16 Hz, and the average predominant frequency is 2.96 Hz; the influence range is about 15 m; the seismic response magnification of the hanging wall is greater than that of the footwall, showing the "hanging wall effect", and the magnification is between 1.64 and 2.38. The research results are of great significance to the seismic fortification of Xi'an ground fissure site engineering.