Dynamic probing

Dynamic sounding is used to determine the density index, of both anthropogenic (fills) and natural soils. This is the basic geotechnical parameter in relation to the non-cohesive soils (sand, gravel, sand-gravel mixes) used by the engineer to the static calculations. The following dynamic soil penetrometers are used: DPL (DPL-10 light), DPM (DPM-30 medium), DPH (DPH-50 heavy) and DPSH (super heavy).

Sounding consists in a dynamic and regulated plunging of the cone into the subsoil with a constant impact energy. The characteristic values ​​corresponding to the number of beats per unit of plunging (10 or 20 centimeters) are obtained as a result of the investigation. The result (based on the appropriate correlations) gives the possibility to determine the degree of compaction of the tested soil.

Dynamic soundings are commonly used for the designation of the density index of the non-cohesive soils for the correct separation of the geotechnical layers. Dynamic soundings are also executed as a quality control tests in the case of embankment formation. The test is carried out the most frequently to verify the subgrade layers, ballast under the flooring, sidewalks, foundations and ramps as well as the road and railway embankments. Control of the soil must also be carried out after completing of the dynamic compaction columns and gravel/stone columns.

Dynamic soundings also allow to verify if the design requirements relating to the densities of the embedded layers have been achieved and indicate the potential need of the stronger compaction or adoption of the alternative solution e.g. soil stabilization.