Soil Investigation under Natural Conditions: DPL, DPSH, SPT, and CPT Soundings
What are the probing methods?
Probing is performed to determine soil strength and other characteristic parameters. We offer dynamic probing, standard penetration, and cone penetration tests:
- Light dynamic probing (DPL) up to ~10 meters deep;
- Heavy dynamic probing (DPSH) up to ~30 meters deep;
- Standard Penetration Test (SPT) in boreholes up to ~35 meters deep
- Cone Penetration Test (CPT) up to ~35 meters deep.
Dynamic probing methods (light, medium, heavy) are classified based on the weight of the hammer used (ranging from 10 to 63.5 kg). The Standard Penetration Test (SPT) differs from dynamic tests in that a sampling tube is used instead of a probe.
Knowing the hammer weight, drop height, and the number of blows required to drive the probe every 0.15 m of penetration depth, it is possible to calculate the energy needed to penetrate the soil. This allows for determining the soil strength.
In the Cone Penetration Test (CPT), a probe equipped with sensors is pushed into the soil at a constant rate of 2 cm/s. Depending on the soil resistance, it is possible to determine soil types as well as their geotechnical parameters.
When conducting a geotechnical soil investigation, the methods and descriptions specified in “Eurocode 7 – Geotechnical design” are used.
