Sugeng Krisnanto
In addition to the volume change due to external load on soils, there is also volume change due to desaturation of soils. Despite
the availability of the theory in the literature for volume change constitutive surfaces for unsaturated soils, its development in Indonesia has
not been explored thoroughly. A preliminary development of the volume change constitutive surfaces for a compacted crushed mudrock is
presented in this paper. The void ratio versus net normal stress curve was obtained from a standard oedometer test. The water content versus
matric suction curve (known as soil-water characteristic curve, SWCC) and the shrinkage curve were obtained from estimation methods. Using
these three curves, four planes in the volume constitutive surfaces were developed: (i) void ratio versus net normal stress plane at zero matric
suction, (ii) void ratio versus matric suction plane at zero net normal stress, (iii) water content versus net normal stress plane at zero matric
suction, and (iv) water content versus matric suction plane at zero net normal stress. Utilizing these four planes, the volume change constitutive
surfaces were calculated based on a prediction method: (i) void ratio constitutive surface and (ii) water content constitutive surface. In addition
to the development of the volume change constitutive surfaces, the result from an initial stage of the development of Ko unsaturated
consolidation apparatus is presented. The apparatus is developed based on the design from the literature.