We have covered the theoretical aspects of volumetric and deviatoric behavior. These concepts extend to both solids and fluids.
Fluids can change their volume, but as the pressure increases they tend to become incompressible and start exerting large forces to resist the change in volume. This behavior is often exploited in designing hydraulic lifts.
Whether you're building a small structure, or just laying paver stones or building a retaining wall, the first step is to compact the soil underneath. This is done using a heavy roller in a process called compaction. Since soil is granular, there is a lot of air-filled voids between the grains and the air does not offer much structural stiffness. So, when we compact the soil, the air is squeezed out and the grains are pressured more tightly and this automatically makes the surface harder. In this process, the volume of the soil changes as the volume of the air void is now filled with sand grains. So, clearly, the soil has the ability to change its volume and this is used in compacting the soil.
There are several other examples in which the volumetric behavior of solids is used in engineering applications. In this lesson, we'll discuss a few such examples in more detail.
Here are the accompanying handout slides for this lesson.