Soil exploration methods:
Soil exploration methods are further divided into two groups:
- Direct methods:
In this method, by making actual excavation through probing, boring, or test pits. Soil samples are taken from the strata of the rocks and soils. Then by performing field test or by performing laboratory test on the sample taken from the site, the GWT characteristics are determined.
- Indirect methods:
These type of methods provides boundaries between the strata of the different composition of the soil, by observing the changes in the electrical resistivity in the soil or the wave velocity of the soil, or may be in some electrical or magnetic field.
These methods provide satisfaction of the visual inspection. Another advantage of these methods is that, they are suitable for best quality sampling, Both disturbed and undisturbed. They do have the capability of assessing difficulties of excavation.