Estimating slope stability by the root reinforcement mechanism of Artemisia sacrorum on the Loess Plateau of China

Abstract

Root reinforcement is considered an important factor contributing to vegetated hillslope stability. The study aims to extend the understanding of spatial variance in the distributions of roots and mechanical characteristics of Artemisia sacrorum (Artemisia gmelinii Web.) regarding root reinforcement after returning cropland to forestland and grassland on the Loess Plateau of China. The Wu and Waldron model (WW model) and infinite slope method were adopted to estimate the sensitivity of root reinforcement to the mechanical characteristics and the distributions of roots. The results demonstrated that 1) over 80% of root parameters were found in the top 0.3 m soil layer, in which the proportions of the densities of root length (RLD), root surface area (RSAD) and root volume (RVD) were 81.7%, 89.9% and 92.7%, respectively. The root parameters declined with increasing soil depth. 2) The tensile characteristics (tensile strength and force) were significantly correlated with the root diameters as power functions. There was a significant difference in tensile strength between the 0 ~ 0.7 mm and other diameter classes, while there was no significant difference amongst the five gauge lengths. 3) The slope safety factor (Fs) of Artemisia sacrorum was always larger than 1, both in different soil depths (0.1 m, 0.2 m and 0.3 m) and at slopes < 45° Artemisia sacrorum could mainly stabilise the slope in the silt loam area of the Loess Plateau of China. These conclusions have a theoretical and practical significance for the slope stability, surface landslides and other geological hazards in arid environments.