## 3 Results and Discussion
### Dynamic Shear Modulus Characteristics
In this study, as shown in Figure 11b, when the moisture content of the intact loess is below its plastic limit, Gmax initially increases and then rapidly decreases as the moisture content increases. With further increases in the moisture content, the rate of the Gmax attenuation slows down, and Gmax gradually stabilizes as it approaches saturation. This trend remains consistent under different confining pressures. However, the landslide deposit is less sensitive to the changes in the moisture content, and the attenuation trend of Gmax is relatively gradual. Regardless of the confining pressure, the Gmax of the landslide deposit is greater than that of the intact loess at the same moisture content. The results indicate that the sensitivity of the landslide deposit to the moisture content is weaker compared to the intact loess. This difference in sensitivity could be attributed to the variations in the material composition, particle arrangement, and structural characteristics of the deposit. The Gmax of the soil is a crucial parameter for assessing the deformation and failure characteristics of the soil under dynamic loading. It holds significant importance in various fields including engineering design, seismic disaster prediction, underground structure design, and foundation engineering. It is closely related to factors such as soil porosity, confining pressure, and the OCR. A power empirical equation was developed by [PERSON] and Black [37] and [PERSON] [38], which considers the influence of pressure, the void ratio, and the over-consolidation ratio on Gmax:  
\[G_{max}=625\frac{A*OCR^{k}}{0.3+0.7e^{2}}P_{a}\left(\frac{\sigma_{c}}{P_{a}} \right)^{m} \tag{3}\]  
where \(\sigma_{c}\) is the effective mean normal stress (kPa), \(P_{a}\) is the atmospheric pressure (kPa), \(k\) is the function of the plasticity index, and \(I_{p}\), when \(I_{p}\) = 0, 20, 40, 60, 80 and \(\geq\)100, \(k\) = 0.0, 0.18, 0.31, 0.41, 0.48 and 0.5. Considering the fact that the over-consolidation characteristics of the undisturbed loess are irrelevant to the stress history, and no additional OCR issue is required, therefore, the OCR values of the undisturbed loess are all 1. In addition, the soil at 4 m of the landslide deposit also exhibits the over-consolidation characteristics which are still related to its structural properties, and thus, the OCR value is also 1. The fitting results for the undisturbed loess and landslide deposit are obtained, as shown in Table 3. The differences in the A and m values of the undisturbed loess with depth reflect the longitudinal variability of the soil properties. The A and m values of the landslide deposit exhibit relatively uniform changes, continuously increasing with depth and water content. In comparison to the undisturbed loess, the A and m values of the landslide deposit have undergone significant variations longitudinally, characterized by a noticeable increase in the A value. Notably, the m value is smaller than that of the shallow-depth, low-water content, undisturbed loess and larger than that of the deep-depth, high-water content, undisturbed loess. The correlation coefficient of the fitting results indicates that the predicted parameters are reasonable, and these parameters can provide references for the maximum dynamic shear modulus of the soils at different depths in this region.