## 3 Experimental Results
### Effect of Different Factors on Blockage Type
#### 3.3.1 Effect of Material Conditions  
The landslide dam consists of landslide materials, so the landslide volume is the most significant factor [28; 37] that directly determines the formation of a landslide dam and the degree of river blockage. Figure 10 shows that the dam blockage type varies as the volume changes. The blockage degree, as well as \(H_{\text{max}}\) and \(H_{\text{min}}\), increase as the volume increases. It can be inferred that the larger the landslide volume, the larger the cross-section of the landslide dam. The landslide material will deposit to form the landslide dam instead of being flushed away by the water flow.  
Figure 10: The variation in experimental river blockage under the influence of landslide volume.  
Figure 9: Proportion of each blockage type.  
The increase in landslide volume could significantly increase the maximum and minimum heights of the landslide dam. As shown in Figure 11, \(H_{\text{max}}\) shows a relatively linear increase with increasing landslide volume. When the landslide volume doubles, the maximum dam height increases by approximately 10-30%. However, the increase in maximum dam height will continuously decrease as landslide volume increases because the deposit will slide upstream and downstream as more material is introduced. The minimum height of the landslide dam also increases significantly with increasing landslide volume. Thus, it can be concluded that the initial volume of the landslide is a key factor controlling the geometric characteristics of the landslide dam. The larger the landslide volume, the larger the dam height, and the larger the cross-sectional area of the dam. A larger landslide volume will also increase the degree of river blockage and the stability of the landslide dam.  
The particle size of landslide material determines the characteristics of landslide movement. Figures 12 and 13 show that as the particle size increases, the location of the highest deposition will significantly shift from the landslide side to the opposite side. This phenomenon will not substantially change the blockage degree or dam heights but will obviously change the dam blockage type. Thus, particle size is a key factor in determining the location of the highest and lowest depositional heights in the channel. In addition, landslides with larger particle sizes are more likely to completely block rivers since they can form dams with smaller height differences.  
Figure 11: The variation in the maximum and minimum dam heights. (**a**) The maximum dam height, and (**b**) the minimum dam height.  
Figure 12: The variation in experimental river blockage is under the influence of particle size.  
Additionally, the deposition of small particles is more sensitive to flow conditions than that of large particles. For the same landslide volume, small particles are more likely to be flushed away than large particles. The portion of deposition transported downstream does not contribute to the deposition height at the intersection of the slope chute and flume. In conclusion, the effects of landslide volume and particle size on deposit geometry and dam blockage type are interdependent. The landslide volume plays a key role in deposit height, which determines the blockage type under the condition of constant water depth.