Here we used numerical simulations to examine the influence of plant roots on soil shear strength as the increase of soil cohesion. Then, we generalized root architecture to be soil bodies consisting of different cohesive strengths. Changes of stress and pressure were simulated within the range of soil within plant roots on the slope. The intensity attenuation method was here used to calculate the safety factor of slope.
Tapered roots were found to be associated with more serious soil loss due to the maximal velocity of 14 m/s within the scope of plant main stems. Widely root distribution in H-type showed a cyclical effect on the slope on condition that flow shear stress was small.
Young trees have little impact on slope stability which is 3.76–7.85% merely comparing to the bare slopes regardless of rainfall. When root distributions are similar in topsoil, the resistances to the radial stress are not obvious. Widely distributed (H-type) and tapered root (VH-type) architecture are recommended in biological engineering projects.