Soil mechanics fundamentals covering weight and volume relationships in three-phase soil systems. The diagram maps soil composition into solid particles, water, and air phases, then derives key volumetric and gravimetric indices including void ratio, porosity, saturation, and specific gravity. These relationships are essential for soil classification, bearing capacity analysis, and foundation design in geotechnical projects. Fork this diagram on Diagrams.so to customize soil state classifications, add project-specific formulas, or embed in engineering reports and educational materials. The phase diagram representation provides a visual foundation for understanding compaction, consolidation, and permeability calculations.