Methods for Studying the Effect of Plant Roots on Soil Mechanical Reinforcement: a Review

Due to the need for engineering construction, a large number of man-made slopes are formed, which easy to induce soil erosion and shallow landslide. The root mechanical reinforcement effect of plants plays an important role in the reinforcement of slopes, and this paper discusses the research methods on it. The root mechanical reinforcement can be divided into main root anchorage and lateral root reinforcement, and experimental research, theoretical calculation model, and numerical simulation are used to quantify the root mechanical reinforcement effect. Different methods should be chosen according to different root growth morphology. The direct shear test is a good research method for shallow root growth depth. For deeper roots, theoretical calculation model is usually used to quantify the root mechanical reinforcement effect. The theoretical calculation model mainly depends on the tensile properties of roots and the distribution characteristics of roots. Therefore, to reduce the error of the theoretical calculation model, it is necessary to obtain high-precision experimental data measured in the field in the future. The theoretical calculation model has been widely used and can be applied to any species. Even if there is still a small amount of error between the quantified actual mechanical reinforcement effect, the error is accepted. At the same time, the theoretical calculation model can compare the root mechanical reinforcement effect of different plants, which is very beneficial for the selection of slope-reinforcing plants. Numerical simulation can be used as an auxiliary means in the research, but there are still challenges in how to deal with the relationship between root and soil and establish the actual root morphology.