The PANDA® portable penetrometer (Penétromètre Autonome Numérique Dynamique Assisté par Ordinateur) is a lightweight, variable-energy dynamic penetrometer. It was created and developed by researchers from the Geotechnical Group of Blaise Pascal University in Clermont-Ferrand, France, together with the R&D department of the French company Sol-Solution, as a technological tool for soil investigation at medium depths, not exceeding 7 meters.

The PANDA® system consists of an ultra-light variable-energy dynamic penetrometer. Its basic operating principle involves driving a 14 mm diameter rod train into the ground with the aid of a standard hammer (2 kg), fitted with a metallic conical tip of either 2 or 4 cm², used respectively for compaction control or soil investigation. For each hammer blow, penetration (e) and cone resistance of the soil (qd) are continuously recorded, based on the transmitted energy and calculated using the Dutch driving formula proposed by Caquot (1956). A microprocessor records the signals automatically, storing cone resistance qd (MPa) and penetration (mm) for every hammer blow. Once the test is completed, the collected data is exported to a computer and processed using the PANDAWin software provided with the equipment.

Subsequently, PANDAWin generates a resistance profile, or penetrogram, showing cone resistance qd (MPa) as a function of depth (m). Through the penetrogram, in soil investigation mode, it is possible to clearly distinguish the presence of different layers or strata and estimate the soil resistance qd of the existing materials.

At Geotecnia Patagonia, the PANDA® penetrometer is used for the investigation of soft or loose soils, for the control of compacted fills, and especially for the acceptance of excavation or foundation bases, in order to verify the consistency or density of fine or granular soils, respectively.