Experimental Study on Shear Strength of Root Composite Tailing Soil Based on Interfacial Bonding

Abstract

At present, the root soil interface bonding is not considered in the root system of mechanical soil-fixing model. The typical restoration plant Amorpha fruticosa, utilizing the widely used Wu model (WWM), the tensile and tensile properties of single root, and the shear strength properties of root soil composite tailing, is analyzed by the tensile tests of plant roots, pullout tests, and shear tests based on the effect of interfacial bond strength; based on the failure mode of root system in root soil, the modified WWM model is used to calculate the increment of shear strength of composite tailing soil. The results showed that ① the relationship between root diameter of A. fruticosa and tensile strength was power function. ② The bond between root and soil becomes more tight, and the pullout strength of the root system increases significantly. ③ When root soil area ratio (RAR) is the same, shear deformation capacity of root soil composite tailing soil increases with the increase of interface bonding strength. Under the condition of the same interface bonding strength, the cohesion of root soil composite tailing soil is greater than that of tailing soil and increases with the increase of RAR, but the change of internal friction angle is not significant. When the pullout strength is added to the plant root prediction model, the soil consolidation effect of the plant root system can be better reflected. The range of the revised coefficient of the WWM model for the root soil composite tailing soil is 0.15~0.37. The research results will provide a theoretical basis and data support for quantifying the ecological restoration and reinforcement capacity of tailing pond shrubs and plants, slope stability, soil and water management, and other ecological soil consolidation capacity of mines.