This chapter covers selected topics in mechanics and soil
mechanics, which are important for an appreciation and understanding of
the mechanical and hydraulic behaviour of unstabilised earthen construction
materials. Stabilised materials are not covered in detail in this chapter,
but aspects of their behaviour are clearly linked to those of unstabilised
materials. The role of water is crucial as is the acceptance that many of the
materials with which we are concerned are what is termed ‘unsaturated’.