## 3 Results and Discussion
### Consolidation Characterization  
The intact loess is a type of soil with strong structural strength and low initial density, and its mechanical properties are closely related to its structural characteristics. Its  
Figure 8: Diagram of grain crushing during the sliding process [30]. Figure 7: Trends of plasticity characteristics of undisturbed loess and landslide deposit. compression and plasticity characteristics also differ from other types of soils. The present study investigated the undisturbed loess and landslide deposit soil using a standard consolidation test. The soil samples were subjected to consolidation at different pressure levels (12.5, 25, 50, 100, 200, 300, 400, 600, and 800 kPa), and the rebound ratio of each level was recorded after 24 h of unloading. The void ratio of the samples after consolidation is \(e_{i}\),  
\[e_{i}=e_{0}-\frac{1+e_{0}}{h_{0}}\Delta h_{i} \tag{1}\]  
In the equation, \(e_{0}\) represents the initial void ratio, \(h_{0}\) represents the initial height of the soil sample, and \(\Delta h_{i}\) represents the deformation of the sample after achieving consolidation stability under a certain level of pressure. The experimental data were processed using the [PERSON]'s [31] program and the [PERSON]'s [32] method was used to plot the compression curve, from which the compression index, pre-consolidation pressure (\(P_{c}\)), and over-consolidation ratio (\(OCR\)) were determined. \[OCR=\frac{P_{c}}{P_{0}} \tag{2}\]  
\(P_{c}\) is the maximum vertical effective stress that a soil was subjected to in the past, and \(P_{0}\) is the existing vertical effective stress. The undisturbed loess has a strong structural behavior at a low water content, which is manifested as a state of over-consolidation, i.e., \(OCR\) is much greater than \(1\). As the water content of the soil sample increases, the structural behavior of the loess gradually weakens, and \(OCR\) tends to approach 1, which is manifested as a normal consolidation [33]. As shown in Figure 9, the initial pre-consolidation pressure of the undisturbed loess is notably higher than the vertical stress at the depths exceeding 5 m. With the increasing depth and moisture content, the pre-consolidation pressure and vertical stress gradually converge. This trend aligns with the typical understanding of the dynamic consolidation pressure in loess. The compression index ranges from 0.13 to 0.33, indicating a soil of moderate compressibility. The upper layer (above 5 m) of the landslide deposit still maintains a pronounced structural behavior, whereas the vertical stress of the soil samples at the depths of 10 m  
Figure 9: The compression index and OCR of undisturbed loess and landslide deposit in different depths. and below progressively surpasses the pre-consolidation pressure. Consequently, the consolidation state shifts from over-consolidation at the surface to normal consolidation and eventually to under-consolidation. The compression coefficient of the soil samples at shallow depths ranges from 0.17 to 0.22, indicating moderate compressibility characteristics. Meanwhile, the compression coefficient of the soil samples at greater depths varies from 0.08 to 0.1, signifying low compressibility characteristics. The intact loess experiences a significant alteration in its compression properties as its structure becomes disrupted during the sliding process and undergoes consolidation after deposition. The upper layer of the intact loess demonstrates characteristics of over-consolidated, under-compacted soil behavior at a low water content, while the deeper layer shows characteristics of normally consolidated, under-compacted soil behavior at a higher water content. The upper part of the landslide deposit exhibits over-consolidated, low-compression characteristics, whereas the lower part shows characteristics of under-consolidation with low compression.