Series of scatter plots illustrating the effect of clay content and friction angle on the cohesion ratio of mixed soils, comparing Babolar sand with Kaolinite and Montmorillonite clays.

Graphs showing the variation of cohesion ratio (c'_int / c'_int,0) with percent of clay (Fc) for different soil types (Babolar sand, Kaolinite clay, Montmorillonite clay) at various friction angles (α = 0°, 22.5°, 45°, 67.5°, 90°).