Abstract: In this paper, the effect of different root content, root diameter and root distribution patterns on the shear strength of the root-soil complex was investigated, and the changes in cohesion and internal friction angle were quantified. The test results show that the interaction between tea tree roots and soil is stronger than that between bare soil, and the soil forms a stronger composite. The shear strength of the soil increased with the increase of root content, and the increase of internal friction angle was significantly higher than that of cohesion, when the root content was 1.0%, the increase of shear strength was about 29%, and the increase of internal friction angle was as high as 31.8%; as the root diameter increases, the shear strength of the soil gradually increases; the differences in root distribution patterns lead to different patterns of shear strength increase, with mixed rooting increasing the shear strength of the specimen by approximately 10% compared to horizontal rooting, and vertical rooting increasing the shear strength by approximately 4% compared to horizontal rooting.

Key words: Tea Tree Root System, Root Content, Root Diameter, Root System Morphology, Shear Strength