Experimental Study on the Constitutive Model of the Betula platyphylla Root System

摘要

The mechanisms of soil reinforcement by root system are illustrated by a series of experiments on the tensile-resistance of the root system of the Betula platyphylla in North China. By investigating parameters such as different diameters, gauge lengths, and rate of extension, complete stress-strain curve shows a straight-line relation with the root system during the initial stage. With an increase of pulling force over its elasticity limit, plasticity of shape takes place in the root system. The complete stress-strain curves gradually deviate from the straight line and reflect the highly nonlinear characteristic. The stress-strain curves reflect more non-linear elastic characteristics with an increase in the diameter. the unified math expression of resistance to tensile stress and the complete stress-strain curve is put forward according to experimental results and theoretical analysis. This paper establishes the elasto-plastic constitutive model of Betula platyphylla and provides the theoretical basis for the mechanical characteristics of its root system. The results show that the model curves are close to the experimental curves.