Aggregate stability is considered an essential indicator of changes in the physical properties of soils, and vegetation roots play a crucial role in the stability of shallow soil aggregates in ionic rare earth tailings piles during ecological remediation. In this paper, the influence of the law of ecologically restored vegetation roots on the stability of shallow aggregates of ionic rare earth tailing piles was investigated by means of field investigation tests, indoor experiments and mathematical statistics. The influence of different types of root systems on the stability of the shallow depth range aggregates of tailings piles was investigated; the correlation between vegetation root systems and the main physical parameters of rare earth tailings was clarified; and a mathematical correlation model characterizing the characteristic parameters of vegetation root systems was constructed. The evaluation index of the stability of rare earth tailings piles was constructed, and the influence of the law of the ecological restoration of vegetation root systems on the strength of shallow aggregates of ionic rare earth tailings piles was revealed. The results of the study showed that compared with the RD (root density), the root characteristic parameter with the largest response weight to the rare earth tailings pile is the RL (root length density), and the root characteristic parameter with the largest response weight to the water content is the RV (root volume). Suitable vegetation roots can effectively enhance the content of shallow large aggregates of rare ionic earth tailing piles. With the increase of the depth of a tailing pile, the content of large aggregates continues to decrease, and the content of micro aggregates continues increasing. This indicates that the vegetation root system changed the shallow soil of the rare earth tailing pile from disorderly to orderly through its own growth pattern, which effectively improved the stability of the shallow aggregates of the tailing pile and improved the physical properties of the tailing.

Herbaceous vegetation roots play a crucial role in improving soil shear strength during ecological restoration. This study investigates the shear strength characteristics of root-soil complexes in ionic rare earth tailings under the influence of various herbaceous plants and evaluates the applicability of the shear strength increment coefficient within the Wu-Waldron Model (WWM). By determining the physical parameters of soil samples and root system characteristics, this study compared actual shear strength increments obtained via direct shear and root tension tests against theoretical increments. The results indicate that the experimentally obtained shear strength increment of the root-soil complex is significantly higher than the value calculated using the standard WWM model. Root reinforcement is primarily concentrated in the 0–10 cm soil layer, with shear strength decreasing as depth increases. The order of shear strength increments for different vegetation types within the same soil layer is: Vetiveria zizanioides > Paspalum notatum Flüggé > Cynodon dactylon (L.) > Setaria viridis. The stress increment correction coefficient for the WWM model applied to these tailings ranged from 1.66 to 8.04. The WWM coefficients are relatively high. Its value range may be influenced by factors such as the physical properties of rare earth tailings, the calculation of the tensile strength spectrum, variations in matric suction, and assumptions regarding root failure. The coefficients derived in this study clarify the influence of different roots on shear strength and provide a valuable reference for the selection and configuration of vegetation in the reclamation of ionic rare earth tailings.