基材土-岩接触面剪切力学性能是生态护坡体系长久稳定的关键，相关研究可为解决基材脱落难题、完善生态防护技术体系提供必要依据和指导。采用自制的原位剪切仪对4种不同粗糙起伏的基材土-岩接触面进行了原位剪切试验，结果表明，基材土-岩接触面剪切应力-位移表现出典型的软化特性，具有明显的初始线弹性变形、弹塑性变形、峰后软化以及残余剪切变形4个阶段。分析发现，文中试验条件下凸起高度算数平均偏差Ra在4 mm以下时，峰值剪切强度增加速度较快，随后呈逐渐减弱趋势；残余剪切强度、峰值剪切位移以及进入残余阶段的剪切位移与粗糙凸起高度算数平均偏差呈近线性正相关关系。可见实施生态护坡时合理地控制坡面粗糙起伏，有助于提高土-岩接触面峰值剪切强度和残余剪切强度，改善其变形性能，对防护体系的长期整体稳定具有促进作用。

Shear characteristic of base material soil-rock interface plays a key role for long-term stability of ecological slope protection system. Related research on this can provide necessary basis and guidance for resolving the substrate failure and improving the ecological protection technology. The self-made in-situ shear apparatus is used in the field shear tests of 4 groups of base material soil-rock interfaces with different roughnesses. Experimental results show that shear stress-displacement of the base material soil-rock interface is characterized by typical shear softening, including 4 stages of initial linear elastic deformation, elastic plastic deformation, the post-peak softening and residual shear deformation. Under the test conditions, it is found that the peak shear strength increases fast when the arithmetic average deviation of asperity (Ra) is about less than 4 mm. For the higher Ra, the increasing gradient shows a slower trend. Residual shear strength, peak shear displacement and shear displacement stepping to the residual stage show the nearly linear positive correlation with Ra. Therefore, for a specific implementation of ecological slope protection, the reasonable control of slope surface roughness will contribute to increasing the peak and residual shear strength of soil-rock interface, so as to improve the deformation performance and the long-term stability of the protection system.