## 4 Conclusions  
This series of tests aimed to conduct an in-depth investigation into the changes in the physical, mechanical, and dynamic properties of loess during the landslides triggered by earthquakes. The goal was to enhance our understanding of the formation mechanisms and movement processes of loess landslides. The following are the summarized conclusions of the study:  
1. The landslide process disrupts the original structure of the loess, resulting in a reduction in soil porosity and increased density. This process also leads to abrasion and the sieving of loess particles, transforming larger particles into smaller ones, thereby forming a more uniform particle size distribution. Within the landslide deposits, the movement and segregation of particles result in variations in the particle size distribution at different depths.
2. Structural disruption and changes in the particle size significantly impact the consolidation characteristics of landslide deposits, leading to a substantial reduction in their compression coefficients. The study also revealed that despite nearly a century of consolidation, the soil in the middle and lower parts of the landslide deposits still exhibits under-consolidated behavior.
3. Although the differences in the maximum dynamic shear modulus between the undisturbed loess and landslide deposits are relatively small, due to the variations in porosity, consolidation characteristics, and other factors, their dynamic shear modulus decay rates are faster in the landslide deposits than in the undisturbed loess. This underscores the importance of considering their physical property differences when assessing the deformation and failure characteristics of these soils under dynamic loading. Additionally, the fitting parameters (A and m) were derived from the experimental results to predict the maximum dynamic shear modulus of both the loess and landslide deposits in the region.  
These conclusions have significant implications for engineering construction and landslide risk assessment in loess regions. They provide valuable insights into the differences in physical properties between the landslide deposits and loess and can be used to improve the engineering design and construction practices. Furthermore, the application of fitting parameters is expected to assist engineers in more accurately assessing the dynamic response of loess under the dynamic loading conditions.  
Methodology, D.P.; investigation, D.P., C.C., X.L. and Y.D.; data curation, D.P.; writing--original draft preparation, D.P.; writing--review and editing, D.P. and W.Q.; funding acquisition, J.B. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China (No. U1939209), and the Scientific Research Fund of Institute of Engineering Mechanics, China Earthquake Administration (Grant NO. 2020 EEEVL0201).  
\begin{table}
\begin{tabular}{l l l l l l l} \hline \hline
**Sample** & \
\begin{tabular}{l} **Water** \\ **Content (\%)** \\ \end{tabular} & \(OCR\) & \(k\) & \(A\) & \(m\) &
\begin{tabular}{l} **Correlation** \\ **Coefficient \(R^{2}\)** \\ \end{tabular} \\ \hline S04 & 4.91 & 5.36 & & 1322 & 0.1820 & 0.994 \\ S10 & 5.33 & 1.79 & & 2869 & 0.1895 & 0.993 \\ S20 & 11.39 & 1.28 & & 2002 & 0.3563 & 0.987 \\ S30 & 24.5 & 0.92 & & 2008 & 0.3875 & 0.998 \\ D04 & 10.9 & 3.71 & & 2802 & 0.2685 & 0.987 \\ D10 & 12.49 & 0.92 & 0.12 & 3224 & 0.2773 & 0.954 \\ D20 & 17.89 & 0.48 & 0.13 & 3570 & 0.2873 & 0.993 \\ D30 & 18.7 & 0.30 & 0.12 & 4263 & 0.2882 & 0.992 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Fitting parameters of Hardin and Black equation for undisturbed loess and landslide deposit.