# Comparative Study of the Seismic Response Characteristics of Three Special Soils
## 1 Introduction
[9] studied the dynamic response of loess slopes under the coupling effect of earthquakes and rainfall through shaking table tests and found that the deformation evolution and instability failure of the slope mainly occur in the top area of the slope, which is divided into four stages: elastic dynamic deformation stage, residual deformation rapidly increasing stage, liquefaction sliding stage and creep sliding stage. [PERSON] et al. [10;11] studied the seismic effects of unsaturated loess in the southern region of Ningxia and found that with the increase in input seismic intensity and water content, the peak acceleration and response spectrum values of the site both show an increasing trend. [PERSON] [12] applied electron microscopy scanning to the field of dynamics and, based on studying the effects of moisture content, consolidation confining pressure, the consolidation stress ratio and vibration frequency on the damping ratio and dynamic shear modulus, explained the reasons for the differences in dynamic characteristics from a microscopic perspective. As the depth changes, the physical and mechanical properties of red soil show a phenomenon of upper hard and lower soft (\"reverse profile\" law), which is exactly opposite to the changes in the physical and mechanical properties of normal soil. The special \"reverse profile\" phenomenon of red soil has an impact on the stability of the site in red soil areas. [PERSON] [13] and [PERSON] [14] used red soil in the southwest region as an example to describe in detail the \"reverse profile\" characteristics of red soil and believed that the special soil-forming conditions of red soil were the main reason for the formation of the phenomenon of upper hard and lower soft soil. [PERSON] [15] conducted indoor experimental research on the stability of residual red soil cutting slopes, and the results showed that rainfall has a significant impact on the stability of red soil slopes. At the same time, it is proposed that the shear strength should be selected as the evaluation index for the stability analysis of red soil slopes. [PERSON] [16] used GeoStudio software 2012.v8.11.1.7283 to analyze the seismic stability of red soil slopes. The research results showed that as the seismic intensity increased, the maximum horizontal displacement of the slope top and slope angle began to increase, and the slope stability coefficient gradually decreased. At the same time, it was noted that rainfall had an impact on the seismic stability of the slope. In standard seismic design, the characteristic spectral period and platform value are important parameters for the response spectrum. Consequently, in recent years, research on the influences of site conditions on the characteristic period and platform value of the response spectrum has attracted increasing attention from both academic and engineering circles. In particular, due to their special engineering and dynamic characteristics, special soils will exhibit unique responses to earthquake loads, causing earthquake disasters that occur in the distribution area to be more serious [17; 18]; therefore, studying the seismic response characteristics at special soil sites has important theoretical and practical significance. A site seismic response analysis is an important method for studying the impacts of site conditions on ground motions. Based on the existing research work, this paper establishes two different soil and special soil models using the SOILQUAKE soil seismic response analysis program. One model is a uniform model. A single ideal soil section is used to study the influences of different special soil sites on the characteristic period and platform value of the design response spectrum under different input ground motion intensities. The other model is a soil section model based on measured data to study different kinetic parameters and the differences in the peak acceleration of the design response spectrum, the characteristic period and the platform value.