A Study on Rainfall-induced Erosion of Land Surface on Reinforced Slope Using Soil Improvement Material

Abstract

Heavy rainfall intensity may cause shallow slope failures and debris flow by rill erosion and scour on land surface.The paper represents the difference between native soil (weathered soil) and reinforced soil, which is mixed by hardening agent with flyash as main material, for investigating experimental findings of rill erosion and erosion. Results obtained from artificial rainfall simulator show that erosion rate of reinforced soil mixed with hardening agent is reduced by 20% because an amount of eroded soil on slope surface is inversely proportional to the increase of soil strength. For example, rainfall of 45mm (at the elapsed time of 25mins in rainfall intensity of 110mm/hr) triggers rill erosion on native soil surface, but the rill erosion on reinforced soil surface does not even occur at 330mm rainfall (at the elapsed time of 3hrs in rainfall intensity of 110mm/hr). As a result of slope stability analysis, it was found that the construction method for reinforced soil surface would be more economical, easy and fast construction technology than conventional reinforcement method.

Development of Eco-Friendly Soil Improvement Agent for Enhanced Slope Stability and Erosion Control in Urban Areas

“…The results of the in situ soil (C-90-0-10) rainfall test showed a clear soil loss in the form of scour immediately after the start of rainfall. Over time, the degree of scour became increasingly severe, and after 15 min, rainwater infiltrated the soil and caused the surface to slide, resulting in failure [2,13].…”

“…To conduct unsaturated seepage analysis for each stratum and apply the experimental constants (a, n, m) of the soil-water characteristic curve, the average of the experimental values published in previous studies was applied [2,14]. Table 7 lists the average values of the soil-water characteristic curve and saturated permeability coefficient by stratum used in the unsaturated seepage analysis.…”

“…Even slopes designed for safety are susceptible to erosion of the ground surface, water infiltration, tensile cracking, and soil deformation caused by debris flows, which can compromise ground structure safety over time. Shallow failure parallel to the slope is a common type of slope failure, which is primarily caused by erosion and scour generated by water flow on the ground surface [1,2].…”

“…Conventionally, the instability of the surface layer or soil erosion is addressed by using fly ash or cement as ground improvement agents for slope reinforcement. However, the use of fly ash significantly declined due to environmental pollution concerns, as noted by Kim et al [2]. In contrast, a soil improvement agent offers a practical and effective slope reinforcement method to prevent debris flows resulting from shallow slope failure caused by rainfall, as emphasized by Edil et al [5].…”