Chapter 10
A Sensitivity Analysis on the Gravity
Erosion on the Steep Loess Slope
Abstract Gravity erosion is a dominant geomorphic process on the widespread steep
loess slopes, yet it is not well understood due to the complexity of failure occurrence
and behavior. This chapter conducted a series of laboratory experiments to test the
stability of different slope geometries and rainfalls and then performed a sensitivity
analysis. The following three types of gravity erosion were observed: landslide,
avalanche, and mudslide. In an event of rainfall, various types of gravity erosion
might emerge in the same period, and mass failures with the same mode and similar
size often adjacently appeared. Climate-driven factors and topography triggers had
prominent influences on gravity erosion. Whether for the total amount or the peak
amount in an experiment, the largest sensitivity parameter on both landslides and
mudslides was that of rainfall duration. The experimental results provide an insight
into the pre-failure mechanisms and processes of steep loess slopes.
Keywords Gravity erosion · Laboratory test · Sensitivity analysis · Rainfall ·
Landform
10.1 Assessment of Soil Erosion Sensitivity
Assessment of soil erosion sensitivity is defined as the possibility of soil erosion
occurrence and identification of areas susceptible to soil erosion when only considering natural factors (Zhang et al. 2013). The main task in landslide susceptibility
assessment is to find out how the causal factors influence the occurrence of landslides
(Melchiorre et al. 2011). The mode of rain-induced mass failure strongly depends
on the initial state of the slope materials, together with the pore water pressure distribution and magnitude of apparent cohesion due to variations in the soil water
content (Zhang et al. 2014; Lourenço et al. 2006). Intense rainfall, soils that are
largely non-cohesive as they become saturated, steep terrain, and intense development are considered to be the major causes of the failures. Loss of pore-water suction,
erosion, and pore-water pressure build-up at shallow depths are the most common
ways through which rainwater affects slope stability, as short-burst rainstorms are
common. The scale of a failure event depends on the intensity, area, position, and
duration of the triggering rainstorm, whereas the antecedent rainfall has relatively
© Science Press and Springer Nature Singapore Pte Ltd. 2020
X. Xu et al., Experimental Erosion,
https://doi.org/10.1007/978-981-15-3801-8_10
151
A Sensitivity Analysis on the Gravity
Erosion on the Steep Loess Slope
Abstract Gravity erosion is a dominant geomorphic process on the widespread steep
loess slopes, yet it is not well understood due to the complexity of failure occurrence
and behavior. This chapter conducted a series of laboratory experiments to test the
stability of different slope geometries and rainfalls and then performed a sensitivity
analysis. The following three types of gravity erosion were observed: landslide,
avalanche, and mudslide. In an event of rainfall, various types of gravity erosion
might emerge in the same period, and mass failures with the same mode and similar
size often adjacently appeared. Climate-driven factors and topography triggers had
prominent influences on gravity erosion. Whether for the total amount or the peak
amount in an experiment, the largest sensitivity parameter on both landslides and
mudslides was that of rainfall duration. The experimental results provide an insight
into the pre-failure mechanisms and processes of steep loess slopes.
Keywords Gravity erosion · Laboratory test · Sensitivity analysis · Rainfall ·
Landform
10.1 Assessment of Soil Erosion Sensitivity
Assessment of soil erosion sensitivity is defined as the possibility of soil erosion
occurrence and identification of areas susceptible to soil erosion when only considering natural factors (Zhang et al. 2013). The main task in landslide susceptibility
assessment is to find out how the causal factors influence the occurrence of landslides
(Melchiorre et al. 2011). The mode of rain-induced mass failure strongly depends
on the initial state of the slope materials, together with the pore water pressure distribution and magnitude of apparent cohesion due to variations in the soil water
content (Zhang et al. 2014; Lourenço et al. 2006). Intense rainfall, soils that are
largely non-cohesive as they become saturated, steep terrain, and intense development are considered to be the major causes of the failures. Loss of pore-water suction,
erosion, and pore-water pressure build-up at shallow depths are the most common
ways through which rainwater affects slope stability, as short-burst rainstorms are
common. The scale of a failure event depends on the intensity, area, position, and
duration of the triggering rainstorm, whereas the antecedent rainfall has relatively
© Science Press and Springer Nature Singapore Pte Ltd. 2020
X. Xu et al., Experimental Erosion,
https://doi.org/10.1007/978-981-15-3801-8_10
151