## 1 Introduction  
During the rapid development of numerous infrastructure facilities, a large number of irrational slope excavation and backfilling projects have destroyed the ecological balance of the native vegetation system, leading to biodiversity degradation, which in turn causes geological disasters such as debris flow, soil erosion, and even desertification [1; 2; 3; 4; 5; 6; 7; 8]. Scientific slope restoration and management is a critical way to improve soil erosion resistance and the regional environment. Conventional slope protection is highly capable and time-sensitive [9]. However, as time passes, it becomes more susceptible to damage from natural and human forces, and the effectiveness of the protection works itself deteriorates, eventually failing to provide protection. Furthermore, traditional protection measures rely heavily on cement, concrete, and other non-renewable materials [10]. The use of large quantities of these materials invariably results in soil salinization and hardness. This is particularly damaging to plant and animal growth, as well as microorganisms growth [11]. Based on the inadequacy of traditional slope protection technology and the strengthening of environmental protection, ecological slope protection technology as a new type of slope protection method has been widely used in engineering construction [12; 13]. Ecological slope protection can perform the long-term function of soil consolidation and environmental beautification. At the same time, it can effectively prevent and control soil erosion and shallow landslides on slopes [14]. At present, ecological slope protection technology mainly uses civil structures or materials for the initial treatment of slopes, and then uses plant protection to reduce soil erosion and restore the ecological environment. The implementation of ecological slope protection technology is a complex project with many factors to improve slope stability: (1) Necessary drainage measures need to be established on the excavated slope. (2) Appropriate support methods need to be adopted according to the geology of the slope, slope height and slope ratio. (3) Select plants with high adaptability, high survival rate and well-developed root system. (4) After vegetation is planted, water and nutrients need to be replenished regularly [11]. Common ecological slope protection techniques are ecological concrete protection and geotextile protection. Eco-concrete slope protection has good air and water permeability and ecological functions, but alkali reduction problems, strength, and durability are yet to be verified [11]. Geotextiles are effective in reducing erosion and subsequent slope degradation processes, but prevent contact between plants and soil, thus affecting plant growth [15]. Therefore, combining traditional slope protection techniques with ecological slope protection techniques can make up for the shortcomings of a single slope protection method. [PERSON] et al. used the anchor reinforced vegetation system for shallow protection of expansive soil slopes to effectively improve the soil and water conservation performance of the slope [16]. [PERSON] et al. adopted the new slope protection method of bolt hinge anchor block and ecological vegetation coverage to effectively improve the slope stability [17]. Vegetation plays a vital role in controlling geological disasters and improving slope stability [18; 19; 20; 21; 22]. The mechanical influence of vegetation on slope stability is mostly due to the reinforcing and anchoring action of plant roots on the soil around the roots: (1) The deep main direct root system anchors the soil to inhibit the sliding of the slope soil layer. (2) The shallow scattered root system is incorporated into the soil for reinforcement, forming a root-soil complex and enhancing the shear strength of the soil. (3) The horizontal root system exerts a traction effect on the soil around the root [23; 24; 25; 26]. Various scholars in China and overseas have made significant contributions to the study of root mechanics.