Study on the Fractal Characteristics of the Plant Root System and Its Relationship with Soil Strength in Tailing Ponds

To study the fractal characteristics of plant roots in tailing ponds and their effect on soil strength, the rhizosphere soil and roots of Amorpha fruticosa and Hippophae rhamnoides, which are widely distributed in ecological restoration areas, were collected. The fractal dimension, root fractal characteristics, soil strength characteristics, and interaction relationships of the two rhizosphere soils were studied. Fractal theory was used to derive the formula for calculating the safety factor of the slope considering the soil and root fractals. The results showed that (1) the fractal dimension of rhizosphere soil of A. fruticosa and H. rhamnoides decreased with increasing vertical profile depth. (2) The fractal dimensions of roots of A. fruticosa and H. rhamnoides decreased with increasing soil depth. (3) The cohesion of the root-soil complex first increased and then decreased, and the fractal dimension of roots was significantly positively correlated with the increase in cohesion. (4) The slope safety factor was positively correlated with the fractal dimension of the soil and root system. It established the theoretical formula of the slope safety factor modified according to the fractal dimension.