Panda probing apparatus

The PANDA probing apparatus is a lightweight dynamic penetrometer with variable stroke energy. The impact speed of the ramming hammer is recorded automatically, which allows the calculation of the ramming energy with each blow, due to the knowledge of the calibrated hammer weight. The penetration is measured simultaneously. 

The probe cone has a cross section of 4 or 10 cm sq. and a top corner of 60° en is attached to the bottom end of a series of modular rods. In accordance with the probe with, the lateral friction on the rods during the striking of these rods is avoided so that the measured ramming energy only concerns the end resistance. The dynamic cone resistance qd is measured with the classic Dutch ramming formula.

The conversion of the dynamic cone resistance qd to the static end resistance qc, based on the origin of development of the classic calculation methods, depends on the type of soil one finds himself in. Seeing as the type of soil is not known a priori from a cone probing, the following ratio is adopted out of security measures (according to Cassan):

• Above level of underground water: qc = 0,80*qd
• Above level of underground water: qc = 0,65*qd

The conic and frictional resistance is processed at each depth stage of 20 cm, for practical reasons. For this, the average of the recorded values is calculated. This will be considered the calculation value for the corresponding soil layer with a thickness of 20 cm.

This apparatus is highly fit for soil research exploration of not easily accessible spaces (backyards, basements, garages, interior renovations, ...) where classic probing of 10 or 20 t is not applicable.