Abstract: In order to investigate the mechanical properties such as the shear strength and the residual strength of the artificially prepared gravely soils, and to provide a basis for the stability analysis of high fill slopes, the in-situ density tests and on-site direct shear tests are conducted in a large fill slope project to study the density, the shear strength, and the residual strength of the artificial prepared gravely soils with different soil-gravel ratios. The results show that the density of gravely soils is influenced by the content and the particle gradation of crushed stones, and when the content of the crushed stones is high, the density is actually lower. Appropriate control of the particle grading when manually mixing crushed stone soil is beneficial for improving the compactness of the soil mass. The shape of the direct shear stress-shear displacement presents three stages: an upward stage, a gradually decreasing stage after reaching its peak, and a stable stage; The higher the normal stress, the greater the corresponding direct shear displacement at the peak strength for different soil-gravel ratios, and vice versa.

Key words: Field Direct Shearing Test, InSitu Density Test, Shear Strength Parameters, SoilGravel Ratio