ABSTRACT
Effects of coarse inclusions on strength behavior of a compacted residual soil were investigated through a laboratory direct shear test program. Factors investigated included inclusion content, size, shape, orientation and spacing, and saturation of matrix materials. It was found that critical inclusion content, below which inclusions have no effect, for this clayey matrix material was between 10% and 20%. The important factors controlling a strength increase of soils are inclusion surface angularity and roughness, inclusion spacing, and height of inclusion perpendicular to shear plane.
