Influence of Root-soil Complex Characteristics of Amorpha Fruticosa on Stability of Loess Slope
[Objective]The effects of water content,root content,and root arrangement on the shear strength of the root-soil composite were analyzed to reveal the reinforcement mechanism of Amorpha fruticosa root system on loess slopes,in order to provide a reference for the ecological protection of loess slopes and engineering practices for improving slope stability.[Methods]A shear test of the root-soil complex of A.fruticosa was conducted using a ZJ strain-controlled direct shear apparatus.This study analysed the effects of various water contents,root contents,and root distributions on the shear strength,with non-root soil serving as the control.Additionally,the FLAC 3D software was used to simulate the influence of the root distribution of A.fruticosa on the stability of the loess slope.[Results]① The cohesion and internal friction angle of the shear strength index decreased with increase in water content.② With an increase in root content,the shear strength exhibited different patterns under different water content levels.When the water content was 9.31%,the shear strength initially increased with an increase in root area ratio(RAR)but then decreased with further increase in RAR.At RAR was 0.15%,the shear strength reached its maximum value.However,when the water content was 15.65%and 17.44%,the shear strength in RAR.③ The"(廾)"shape root arrangement can significantly improve the shear strength of the root soil complex.When the water content was 17.44%,the average shear strength of the root-soil composite increased by 31.81 kPa compared to the control.④ Numerical simulation results indicated that both root length and the angle between the main root and vertical direction were positively correlated with stability.[Conclusion]The findings from laboratory tests and numerical simulations demonstrated that A.fruticosa can enhance the stability of loess slopes and that an interlaced planting pattern of A.fruticosa provides a more effective protective effect.