Effect of water content on permanent deformation of fine/coarse soil mixtures with varying coarse grain contents and subjected to multi-stage cyclic loading

An interlayer soil in ancient rail tracks was identified as a mixture of ballast grains and subgrade fines. As the permanent strain $${\varepsilon }_{1}^{p}$$ such affected by water content, cyclic triaxial tests were performed, under varying contents fines wf coarse grain fv. Comparison between present previous studies showed significant effect sample preparation method on . In study, constant fine dry density ρd-f maintained, leading to an unchanged suction whatever fv value. this case, only reinforcement identified. By contrast, studies, global ρd kept constant, resulting decrease with increasing consequently suction. when negative decreasing prevailed positive fv, increased.