Mechanical reinforcement by plant roots increases the soil shearing strength. The geometric and distribution characteristics of plant roots affect the soil shearing strength. Current research on the shear strength of rooted‐soil is mostly based on direct shear tests with a fixed shear surface and thus cannot reflect the actual failure state of the rooted‐soil. In this study, Golden Vicary Privet was used to create a rooted‐soil, and a triaxial test method was used for soil mechanical property analysis. The influence of the root geometry (root diameter and individual root length) and distribution characteristics (root density and root distribution angle) on the rooted‐soil shearing strength was studied by controlling the root morphology in the specimens. According to the results, both the root geometry and distribution characteristics affect the rooted‐soil shearing strength. For a fixed total length of the roots, the longer the individual root length is, the better the soil shearing strength is. In addition, the reinforcement effect of the root system increases as the angle between the root and the potential failure surface increases. The results also show that the root system significantly enhances the soil cohesion while only minimally affecting the internal friction angle. The maximum rooted‐soil cohesion is 2.39 times that of the plain soil cohesion, and the maximum internal friction angle of rooted‐soil is 1.24 times that of plain soil. This paper provides an approach for the determination of the rooted‐soil strength and a rationale for vegetation selection in ecological slope reinforcement applications.

Soil deformation control is the key to shaft support. To better control soil deformation, improve construction efficiency, and reduce pollution, this study proposed a prefabricated prestressed supporting structure. The structure consisted of prefabricated steel structure units and special prestressed components. The structure units were applied to retain the soil. The screws were used for prestressing. Field prototype tests were conducted to assess the support effects and analyze the stress and deformation behaviors of the shaft. The earth pressure, the stress in the structure unit, and the lateral displacement of the soil were monitored. The measured earth pressure varied between the earth pressure at rest and the passive earth pressure. The stress of the supporting structure was far less than the yield strength of steel. Changes in the earth pressure and structural stress can be divided into four stages: rapid attenuation, fluctuation, slow change, and stabilization. Both the earth pressure and the structure stress completed the major attenuation within three days of prestressing. The surrounding soil moved out from the shaft under prestress conditions and exhibited an obvious space-time effect. The study of stress and deformation provides guidance for the construction of newly prefabricated prestressed structures.