In‐Situ Shear Test of Soil‐Root Systems

In situ shear tests were performed on soils reinforced by roots. Analytical models of soil‐root interaction presented in a companion paper were used to compute the forces in the roots and the contribution of the roots to the shearing resistance of the soil‐root system. General agreement between measured and computed shearing resistances was taken as verification of the analytical models. Results of the computations also showed the influence of the dimensions of the shear box on the measured shear strength. The shear strengths measured by the in situ tests were found to be less than the shear strength along a potential slip surface in slope stability problems. Methods for estimating the shear strengths for stability analysis are presented.