# Comparative Study of the Seismic Response Characteristics of Three Special Soils
## 5 Calculation Results and Analysis
### Analysis of the Calculation Results of the Actual Soil Profiles
Figure 6: Schematic diagram of the deviation of characteristic parameters obtained by comparing the values of different kinetic parameters with the measured values. (**a**) Schematic diagram of characteristic period deviation; (**b**) Schematic diagram of platform value deviation; (**c**) Schematic diagram of peak acceleration deviation. In summary, the maximum deviations between the peak acceleration and design response spectrum characteristic parameters of the three special soils and the actual measured values mostly appear at the minima. Therefore, when these three special soils are present at an actual project site and measured data are lacking, this article does not recommend using the minimum values in the statistical ranges of the special soil dynamic parameters. Comparing the results of the three special soil dynamic parameters under different strength conditions with the actual measured values reveals that with the input ground motion intensity, if the actual project is located in an area where the seismic fortification intensity is high (VIII or IX) and there are special soil layers in the area, these statistical values should not be used for the dynamic parameters of the special soil layers, and experiments should be conducted to acquire the corresponding values. According to the deviations in the peak accelerations of the special soils under different dynamic parameter values and the differences in the characteristic parameters of the design response spectra from the actual measured values, this article gives the recommended values for the dynamic shear modulus ratio and damping ratio in the typical areas of these three special soils (see the details in Table 14). Figure 7 compares the suggested curves of the dynamic shear modulus ratio and damping ratio with the shear strain in the typical areas of the three types of special soils. Evidently, the difference among the dynamic shear modulus ratios of the special soils is small, decreasing in the order of silty clay, loess and laterite. In contrast, the damping ratio is more complicated. The damping ratio of loess varies greatly; when the shear strain is lower than \(5\times 10^{-5}\), the damping ratio of loess is smaller than that of either laterite or silty soil, but when the shear strain is higher than \(5\times 10^{-5}\), the damping ratio of loess exceeds that of laterite, and when the shear strain is higher than \(3\times 10^{-3}\), the damping ratio of loess exceeds the damping ratio of silty soil and becomes the maximum. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multirow{2}{*}{**Parameter**} & \multicolumn{8}{c}{**Shear Strain (\(\times 10^{-4}\))**} \\ \cline{3-10}  & & **0.05** & **0.1** & **0.5** & **1** & **5** & **10** & **50** & **100** \\ \hline Silty Clay & G/Gmax & 0.9953 & 0.9906 & 0.9548 & 0.9139 & 0.6853 & 0.5253 & 0.1856 & 0.1028 \\  & \(\lambda\) & 0.0342 & 0.0426 & 0.0707 & 0.0873 & 0.1336 & 0.1531 & 0.1836 & 0.1900 \\ Clay & G/Gmax & 0.9959 & 0.9919 & 0.9611 & 0.9257 & 0.7218 & 0.5704 & 0.2192 & 0.1227 \\  & \(\lambda\) & 0.0368 & 0.0453 & 0.0734 & 0.0901 & 0.1358 & 0.1562 & 0.1879 & 0.1957 \\  & G/Gmax & 0.9886 & 0.9806 & 0.9170 & 0.8593 & 0.6123 & 0.4764 & 0.1919 & 0.1099 \\  & \(\lambda\) & 0.0081 & 0.0132 & 0.0425 & 0.0667 & 0.1351 & 0.1575 & 0.1840 & 0.1892 \\  & \(\sigma\)/Gmax & 0.9934 & 0.9865 & 0.9372 & 0.8844 & 0.6354 & 0.4878 & 0.1863 & 0.1083 \\  & \(\lambda\) & 0.0117 & 0.0150 & 0.0297 & 0.0411 & 0.0827 & 0.1046 & 0.1453 & 0.1555 \\ \hline \hline \end{tabular}
\end{table} 
Table 14: List of recommended values of dynamic parameters for special soils in typical areas. Figure 7: Comparison of suggested curves of dynamic shear modulus ratio and damping ratio with shear strain for three special soils.