为了研究岩质边坡生态防护中根土复合体与岩石接触面的作用机理，通过构建不同植物种类、护坡土体类型与岩石风化程度的接触面物理模型，在天然应力条件下，开展了根土岩接触面的直接剪切试验，揭示了接触面抗剪强度和剪切位移的变化规律，并分析了植物根系形态、护坡土体类型、岩石风化程度对接触面抗剪强度的影响机理。结果表明，植物根系通过护坡土体并伸入基岩裂隙，显著提高了剪切带土体抗剪强度和土岩交界面抗滑移能力，从而增强了护坡土体与岩石的整体性；接触面抗剪强度与植物根系竖向延伸程度及岩石风化程度正相关，相较于无植物工况，当种植香根草时峰值抗剪强度提高了53.9%，强风化基岩条件下提高峰值强度达22.4%。相较于普通土，添加有黏合剂与团粒剂的基材土可显著提高土体抗剪性能，提升接触面峰值抗剪强度达20.1%。

To investigate the mechanism of interaction between root-soil composites and rock interfaces in the ecological protection of rocky slopes, physical models of interfaces were established, considering different plant species, types of soil for slope protection, and degrees of rock weathering. Under natural stress conditions, direct shear tests on the root-soil-rock interfaces were conducted. The variation patterns of shear strength and shear displacement at the interfaces were revealed, and the influence mechanisms of plant root morphology, types of protective soil, and rock weathering degree on the shear strength of the interfaces were analyzed. The results indicate that plant roots, penetrating through the slope protection soil and into the bedrock fissures, significantly enhance the shear strength of the soil in the shear zone and the anti-slip capacity of the soil-rock interface, thereby improving the overall cohesion between the slope protection soil and the rock. The shear strength of the interface is positively correlated with the vertical extension of plant roots and the degree of rock weathering. Compared to scenarios without plants, the planting of vetiver grass increased the peak shear strength by 53.9%, and under highly weathered bedrock conditions, the peak strength increased by 22.4%. Compared to ordinary soil, substrate soil containing binders and aggregating agents significantly improved the shear performance of the soil, increasing the peak shear strength of the interface by 20.1%.