A displacement-based model for estimating the shear resistance of root-permeated soils

Aims

This paper presents a displacement-based model for predicting the relationship between the increase in shear resistance and shear displacement for soils permeated with an entire plant root system.

Methods

The root force in the root system is estimated based on the shear deformation developed in the soil. This displacement-based model takes a number of factors into account, including the distribution of the shear deformation in the soil, the root orientation, the mobilized root forces, and the root properties.

Results

The proposed model reasonably captures the relationship between the increase in the shear resistance (ΔS) and the shear displacement, as shown by a comparison of the predicted results with data from in situ shear tests.

Conclusions

Major findings are the following: (1) the ΔS value increases considerably with increasing b coefficients, which are used to describe the deformed shape of the shear zone, and Young’s moduli of roots at the early stage of shearing; (2) the ΔS value increases significantly with the τ value at large shear deformations; (3) short roots play an important role in the contribution of root systems to the shear resistance of the soil. However, the success of the model relies on the appropriate estimate of the deformation characteristics on the shear zone and the soil-root bond strength.