Combined Influence of Vegetation Roots and Biochar Amendments on Soil Water Characteristics of Silty Sands

Abstract

Shallow slope failures are often caused by water infiltration during heavy rainfall, which reduce soil shear strength and leads to instability of slope. The hydraulic behavior of unsaturated soils such as soil water characteristics plays a critical role in maintaining slope stability under such conditions. This study investigates the effects of vegetation roots and biochar on the soil water characteristics of sandy soils. The one-dimensional soil column experiment was conducted, incorporating moisture sensors and tensiometers to capture monitoring data. The van Genuchten model was applied to characterize the water retention behavior of treated soils. Results demonstrate that integration of vegetation roots and biochar significantly improve soil water retention and suction characteristics. These findings offer quantitative insights valuable for geotechnical engineers, and researchers, supporting the development of predictive models for rainfall-induced slope stability and sustainable slope management.