The purpose of this section is to introduce some of the constitutive models devoted to routine, as well as advanced, pavement analysis and design. For all these models, moisture or water pressure are not taken into account. They are written, here, in terms of total stresses — i. e. the effects of pore water pressure and/or pore suction are subsumed into the mechanical response of the materials and are not explicitly described.
Nowadays, models for subgrade in pavement engineering have been split in two categories dealing with the main mechanical behaviour which needs to be taken into account:
• resilient behaviour (see Fig. 9.3); and
• long term elasto-plastic behaviour.
