Infiltration and Failure Behavior of an Unsaturated Soil Slope under Artificial Rainfall Model Experiments
2. Laboratory Methods and Materials
2.1. Physical Properties of the Soil
2.2. Experimental Procedure
2.3. Artificial Rainfall System
2.4. Experimental Slope
3. Results and Discussion
3.1. Effect of Rainfall Intensity on Infiltration Behavior
3.2. Effect of Initial Moisture Content of Compaction on Infiltration Behavior
3.3. Effect of Relative Compaction on Infiltration Behavior
- During the initial rainfall infiltration, the soil saturation was observed to be higher at the toe of the slope compared to other areas of the slope, and it gradually advanced towards the crest, resulting in the formation of a wetting band along the slope surface. As the rainfall duration increased, the wetting band progressed downwards along the slope.
- Failure began at the crest of the slope and junction with the slope. Soil erosion was the main cause of slope failure due to the high rainfall intensity.
- As the rainfall intensity increased to 160 mm/h, the majority of the rainfall on the slope became surface runoff. Therefore, an increase in rainfall intensity caused only a slight increase in the infiltration rate, indicating that once significant runoff was initiated, increasing the rainfall intensity had minimal effect on the infiltration behavior of the rainfall.
- The slope compacted at the dry of optimum had a higher infiltration rate compared to slopes compacted at OMC or wet of optimum, which made it more vulnerable to failure.
- As the degree of relative compaction increases, the infiltration time also increases, resulting in a greater generation of surface runoff at a fixed rainfall intensity. However, a higher degree of relative compaction causes the soil to become more tightly packed, reducing its susceptibility to soil erosion caused by surface runoff.
- Relative compaction is the most significant factor that affects infiltration rates, followed by the initial moisture content of the compacted slope.
- Although the intensity of rainfall had only a minor impact on the infiltration rates, it had a significant effect on the severity of scour due to the substantial amount of surface runoff, particularly when the soil slope is compacted at low relative compaction.
Data Availability Statement
Conflicts of Interest
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|Specific gravity, Gs||2.65|
|Liquid limit, LL (%)||30|
|Plastic limit, PL (%)||26|
|Plasticity index, PI (%)||4|
|Clay fraction (grain size < 2 μm), CF (%)||42|
|Optimum moisture content, OMC (%)||24|
|Maximum dry density, γdmax (g/cm3)||1.55|
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Yang, S.-R.; Huang, L.-J. Infiltration and Failure Behavior of an Unsaturated Soil Slope under Artificial Rainfall Model Experiments. Water 2023, 15, 1599. https://doi.org/10.3390/w15081599
Yang S-R, Huang L-J. Infiltration and Failure Behavior of an Unsaturated Soil Slope under Artificial Rainfall Model Experiments. Water. 2023; 15(8):1599. https://doi.org/10.3390/w15081599Chicago/Turabian Style
Yang, Shu-Rong, and Li-Jie Huang. 2023. "Infiltration and Failure Behavior of an Unsaturated Soil Slope under Artificial Rainfall Model Experiments" Water 15, no. 8: 1599. https://doi.org/10.3390/w15081599