3. Soil classification

3.1 Principle of soil classification

Soil classification systems are designed to classify soils into families with the same or very similar geotechnical characteristics. They can therefore be used to group together the large number of samples collected during a drilling campaign and to draw up geotechnical cross-sections of the terrain.

These cross-sections are invaluable to the engineer. They complement geological data, which is not the same as geotechnical data: soils of the same geological origin can have very different geotechnical properties, and vice versa.

There are many different soil classification systems:

• some are based on the suitability of the soil for a particular civil engineering...