Investigating the Effect of Nandina domestica Roots on the Reinforcement of Unsaturated Silty Clay Soil

The interaction between plant roots and soil plays a crucial role in enhancing shear strength, particularly in erosion-prone regions. This study investigates silty clay soil reinforced with Nandina domestica, a shrub with a fibrous root system suitable for bioengineering applications. A total of ۷۲ direct shear tests were conducted on rooted and rootless soil at four depths (۰-۵, ۵-۱۰, ۱۰-۱۵, and ۱۵- ۲۰ cm). Soil shear plane images were processed to calculate the root area ratio (RAR), defined as the ratio of root surface area to the total soil surface area. Sensitivity analysis using the Morris method was employed to better understand the influence of soil depth, root weight density (RWD), moisture content, and normal stress on soil reinforcement. The results demonstrate that roots reduce soil shear displacement while increasing shear strength. Finally, a data-driven polynomial equation was proposed to describe the root-soil reinforcement behavior.

کلیدواژه ها:

direct shear test ، root-soil interaction ، mechanical root effects ، root area ratio (RAR)