Saturated coarse-grained soils (mostly sands) are prone to developing pore water pressure (PWP) when sheared in undrained conditions. If different sands are prepared with the same preparation method and tested under the same conditions (consolidation stress, load amplitude, etc.), they will show different tendencies in the PWP build-up. Obviously, this tendency depends on the granulometric properties of the tested sand and can thus be considered an index property (analogous to the loosest or densest soil state). A simplified cyclic shear test for the investigation of the PWP build-up in sands is presented in this research. The principle of this experimental procedure is based on the evolution of the PWP during cyclic shearing of a water-saturated sand specimen. The procedure can be divided into three phases. At the beginning of the test, a de-aired sand-water mixture is installed in the membrane using a funnel. As a result, high saturation of the soil specimens after installation is obtained in case of any sand. The effective stresses
are increased by applying negative pressure (suction) to the soil specimen. Cyclic loading is applied to the top cap of the specimen in the horizontal direction, which creates a kind of simple shear deformation of the soil specimen. Undrained conditions during the experiment allow for the PWP build-up. The duration of a single shear test, including specimen preparation, is approximately 30 minutes. By evaluating the rate of the measured PWP at different initial relative densities, the dependency of the PWP build-up of the tested soil on the variation of the relative density can be determined. This enables a comparison of the sensitivity of different soils to the development of the PWP. The experimental procedure was validated on several sands using the results of the undrained cyclic triaxial tests. Furthermore, the dependence of the pore water pressure development on various influencing factors (relative density, degree of saturation, load amplitude, consolidation stress, etc.) was investigated. This method aims to assign an index value to every tested sand and thus quantify its sensitivity to density changes with respect to liquefaction