ABSTRACT
All natural soil consists of at least three primary components, solid (mineral), void (not occupied by mineral), and water. Proportions of these components vary dramatically between and within various soil types. This chapter explores some of the physical attributes of a bulk soil and how the soil responds to mechanical forces. Concepts of density, volume, stress-strain, and applications of these factors (as slope stability and compaction) are presented, along with example calculations. The goal of compaction is to increase the soil density (reduce void ratio) and thus increase the shear strength. Compaction methods for cohesionless soil (sand and gravel) include (in order of effectiveness): vibration, watering, and rolling. The chapter also focuses on the shear strength and stability of soils in their natural state. Shear strength of soil results from a combination of cohesion and internal shearing resistance. Proper placement procedures will increase shear strength, reduce permeability, or decrease settlement.
