Closure to "anisotropic hydraulic conductivity and critical hydraulic gradient of a crushed sandstone-mudstone particle mixture"

A closure is presented to the discussion of Anisotropic hydraulic conductivity and critical hydraulic gradient of a crushed sandstone-mudstone particle mixture by Salahou, Jiao, and Yousif (2017). The relationship between the critical hydraulic gradient and the uniformity coefficient can be limited to two curves. The internal erosion mechanism of soils with different particle grade curves is different. The maximum diameter of fine particles of different particle grade curves can be calculated by a lot of methods. The density of the original paper is the average density. The anisotropic hydraulic conductivity is caused by uneven density distribution. The hydraulic conductivities are tested on the saturated soils. The saturated hydraulic conductivity can be regard as a constant value for a saturated soil.