The Shear Strength of Root–Soil Composites in Different Growth Periods and Their Effects on Slope Stability

The instability of bare slopes is a prevalent concern. The root system of herbaceous vegetation enhances the shear strength of shallow slope soil. This study investigated the mechanism of the root-soil system as well as the effects of different influencing factors on the shear strength of the soil and slope stability. In particular, indoor experiments were conducted on rootless undisturbed soil (RUS) and undisturbed soil with a root system (USRS) using a triaxial compression apparatus to analyze the slope stability of composite soil with a Tagetes erecta root system. Significance tests and correlation analysis of the factors affecting shear performance were conducted. The slope reinforcement effect by the plant root system was simulated under 24 working conditions using the MIDAS finite element method. The results revealed the influence of the root content, moisture content, and stress on the shear strength of USRS, as well as the contribution degree and influence of these variables on the slope stability. Both RUS and USRS exhibited strain hardening during shearing. A strong negative (positive) correlation was observed between the internal friction angle (φ) (cohesion (c)) of the USRS and the root content (moisture content). The maximum deviatoric stress during shear failure of the USRS was 1.29 times higher than that of the RUS. Moreover, the root content was positively correlated with the slope safety coefficient and the slope of the line under different working conditions, whereas the slope angle was negatively correlated with the slope safety coefficient. The reinforcement effect by the root system resulted in a 11.2% increase in the safety coefficient and the improved stability of slopes with an angle larger than 1.5%. The findings of this study provide new insights into shallow slope stability in practical slope protection projects.

Section: Shear Strength Expression Of the Soil-root Compositementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Shear Strength Analysis and Slope Stability Study of Straight Root Herbaceous Root Soil Composite

Wang,

Wang

2023

“…However, this construction has had detrimental effects on soil structure and the ecological environment, resulting in numerous exposed slopes and an increased risk of geological disasters such as landslides and debris flows [1]. In order to restore damaged slope structures and the natural ecological environment, slope vegetation restoration technologies such as artificial grass planting and concrete vegetation slope protection are relatively mature [2][3][4]. The roots of the plants strengthen the slope in terms of structure and soil water reduction [5].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of the Soil Water Dissipation Law of Vegetated Slopes under Natural Evaporation Conditions

Xiao,

Liu,

Wan

et al. 2024

Self Cite

Under the combined action of soil evaporation and vegetation transpiration, the law of soil water dissipation at different depths of vegetated slopes is unknown and the related influencing factors are unclear. In this paper, six large-scale slope models were constructed for long-term dynamic monitoring of soil water. The effects of slope ratio and vegetation on the dynamic changes in soil water at different depths were analyzed. Pearson correlation analysis was used to analyze the relationship between slope conditions, meteorological factors, and soil water dissipation. The results show that under the condition of natural evaporation, slope ratio has little effect on the dynamic change in soil water in bare slopes. However, the greater the slope ratio of vegetated slopes, the faster the soil water decreases in the 40 cm depth range. Additionally, soil water dissipation follows a logarithmic functional relationship with evaporation time in both bare and vegetated slopes. The correlation between slope conditions and soil water dissipation is stronger than that of meteorological factors. The research results can provide some theoretical support for exploring the hydrological effects of vegetated slopes.

“…Wang et al [10] suggested that an increase in the number of roots significantly enhances the shear strength of a root-soil composite. Kong et al [11], Lian et al [12], and Zhou et al [13] considered that the distribution pattern of roots notably affects the shear strength of a root-soil composite, with the most pronounced enhancement observed when roots are intermixed or intersected. Xu et al [14], Wang et al [10], and Ajedegba et al [15] discovered a positive correlation between the development of lateral roots and a root-soil composite's resistance to shear deformation.…”

Section: Introductionmentioning

confidence: 99%

Integrating Root Morphology Based on Whole-Pullout Test of Model Roots: A Case Study

Zhai,

Zhang,

Zhang

et al. 2024

To investigate the sensitivity and significance of different morphological characteristics of plant root systems on vertical pullout resistance, this study considered four main influencing factors: the number of lateral roots, taproot length, the branching angle of the lateral root, and the unit weight of the soil around the root. PC plastic model roots were employed to conduct a vertical pullout orthogonal experiment. A comprehensive μX theoretical analysis method based on the whole root system pullout test was applied for a stress analysis on root segments. Based on the results, the factors affected the vertical pullout resistance of plant root systems in the order of number of lateral roots > taproot length > unit weight of soil around the root > branching angle of the lateral root. When the number of lateral roots increased from 2 to 3, the vertical pullout resistance increased by 64%. Also, when the taproot length increased from 50 to 60 cm, the vertical pullout resistance increased by up to 46%. Furthermore, the unit weight of soil around the roots had a positive linear correlation with vertical pullout resistance. Based on the results, the number of lateral roots and the taproot length were the primary factors affecting the magnitude of the root system’s vertical pullout resistance. When selecting plants for slope protection, plant types with a larger number of lateral roots and longer taproots should be considered as the two most significant factors for achieving a better slope protection methodology.