research data（Physical and mechanical properties of root reinforced soil-rock mixture based on CT scanning and direct shear methods）.xlsx

Shallow surface damage often occurs in soil-rock mixture slopes, and vegetation roots are often used to improve slope stability. However, the theoretical research on the influence of vegetation on slope stability lags behind engineering practice, especially the reinforcement mechanism of roots on rock slope is not clear. To investigate the synergistic effects of root systems and soil-rock interactions on the shear performance of soil-rock mixtures, this study focused on a soil-rock mixture slope in Nanjing, Jiangsu Province, China. The research examined the reinforcing impact of Eleusine indica, a typical gramineous plant, on the soil-rock mixture. By integrating direct shear tests with X-ray CT scanning, a simplified complete random test model was employed to analyze the significant relationships between shear strength and factors such as soil dry density, rock content, and root content. Pore analysis of the CT scan results for root-containing samples revealed a transition phenomenon between connected and isolated pores along the root growth direction, elucidating the underlying mechanisms. Utilizing the root model Wu-Waldron Model (WWM) and soil pore structure, the study explained the variations in shear strength parameters of the root-reinforced soil-rock mixture. The findings indicated a significant correlation between block stone and root shear strength interaction at pressures of 300 kPa to 400 kPa. Roots facilitated the transformation of internal pores from connected to isolated states within the soil-rock mixture. Internal stones promoted root reorientation, increasing the root-soil contact area and enhancing pore transformation. The volume of connected pores decreased by 20.8% and 26.7% at dry densities of 1.3 g/cm³ and 1.1 g/cm³, respectively. The structural stability of the soil-rock mixture improved, mitigating deformation and strength reduction caused by single-structure crushing. The enhancement of the root system increased the sample's shear strength, with cohesion in the shear strength parameters showing an upward trend, peaking at a 79.3% increase, while the internal friction angle exhibited a downward trend, with a maximum decrease of 12.2%. The study also explored the influence of block stone content on cohesion contribution within the WWM. These results elucidate the role of root systems in strengthening soil-rock mixtures and compare this enhancement to root-reinforced soil, providing a foundation for preventing and controlling shallow slope instability.