Sampling Techniques

Soil columns can be sampled with a high degree of precision and undisturbed soil structure without the use of heavy duty equipment using the unique sampling technology for mineral soils developed and patented by UGT. The sampling device guarantees a vertical passage of the lysimeter vessel down to the sampling depth of the soil monolith and cuts the contour of the soil monolith using a milling device which is guided concentrically around the lysimeter vessel. Due to the cutter on the face of the lysimeter vessel, the final contour of the soil monolith is formed. The lysimeter vessel accommodates the soil column to shape. Only low axial forces are required to cut the lysimeter due to reduction of the sheath friction. The soil monolith is not deformed during extraction and keeps its natural structure. For quality assurance purposes, the cutting process is monitored by a remote camera. On reaching the sampling depth, the soil column is separated from the surrounding soil area by a cutting device. After the monolith has been completely cut, it is held in place by the profile holder on the cutting device, acting as a temporary seal of the lysimeter vessel so that the monolith can be lifted safely from the sampling pit after cutting.

OLYMPUS DIGITAL CAMERA

Lysimeter

 

OLYMPUS DIGITAL CAMERALysimeter

Xray and computer tomography examinations of the soil columns extracted using this technology have shown that no cracks or structural changes occur within the monoliths using this method. All in all the use of lightweight technology impairs the extraction point only minimally and no special requirements are placed on the properties of the ground. Furthermore, this method of extraction is very space-efficient so that the surrounding area is influenced as little as possible when extracting the soil columns. After extraction of the monoliths, the soil profile in the extraction pit is undisturbed and easily visible. This permits a good assessment of the soil profile in the lysimeter vessel and the taking of soil ring samples for laboratory investigations into soil properties. Special lysimeter vessels and patented sampling technologies have been developed for the challenges presented by organic soils particularly in bog land. Large organic soil columns can be investigated using the Moor Lysimeter. For this purpose, the lysimeter vessel is trough-shaped, 4 m long, 1 m wide and 1.5 m deep. The length of 4 m facilitates research of the lateral flow processes which are frequently to be observed in bog lands.