Correlations between soil properties

A wide variety of parameters are used to describe the physical and mechanical properties of soils:

• identification and state parameters (porosity, void index, density, relative density, Atterberg limits, etc.);

• deformability parameters (compression and swelling indices, odometric modulus, pressiometric modulus, etc.);

• resistance parameters (cohesion and angle of internal friction, pressuremeter limit pressure, static or dynamic cone resistance, etc.);

• permeability parameters.

It is very rare for all these parameters to be measured at a sufficient number of points on a given site to be able to assess the entire soil mass. Usually, geotechnical reconnaissance is limited to the strict minimum, with values of some parameters available at some points and other parameters at others. The geotechnical engineer has to make the most of this scattered information and draw up a geotechnical cross-section representative of the site under study.

It is within this general framework that the use of correlations between the physical and mechanical properties of soils can make an effective contribution to the geotechnical engineer's synthesis work.

This article explains how such relationships can be established, and gives some examples of correlations between parameters derived from laboratory tests and in-situ tests.