Soil-water retention behaviour of fine/coarse soil mixture with varying coarse grain contents and fine soil dry densities

The interlayer soil identified in conventional French rail track corresponds to a mixture of fine and coarse grains. To investigate the role fines soil-water retention property such mixture, different grain contents f v dry densities ρ d–f were considered. filter paper method was applied measure matric suction. Mercury intrusion porosimetry tests performed observe microstructure soil. In terms gravimetric water content w with suction ψ, curve (SWRC) significantly affected by for ψ < 715 kPa, while independent > kPa. Interestingly, this threshold corresponded delimiting pore diameter bi-modal soil, which separated micropores from macropores. degree saturation S r SWRC full range, it . These findings help better understand results samples where density d is kept constant: an increase resulted decrease changed accordingly. case, both mechanical behavior.