Sonderingen

Sonderingen are geotechnical investigations into the subsoil conducted to determine its properties and behavior for civil engineering projects. They typically combine fieldwork, such as drilling boreholes and sampling, with in-situ tests and laboratory analyses. The goal is to establish soil stratigraphy, geotechnical properties, and groundwater conditions to support foundation and earthworks design.

Field methods may include boreholes, test pits, and trenching; collected samples may be disturbed or undisturbed depending on the test requirements. In-situ tests commonly used are the Standard Penetration Test (SPT), Cone Penetration Test (CPT) with or without pore pressure measurement (CPTu), vane shear tests, and, in some cases, plate load tests, dilatometer and pressuremeter tests. Piezometers or piezometer tubes monitor groundwater levels during investigations.

Laboratory testing on samples provides particle size distribution, Atterberg limits, natural water content, dry density, moisture content, and strength parameters from shear tests (e.g., triaxial or direct shear). The results are integrated into a geotechnical interpretation that informs bearing capacity, settlement estimates, seepage analysis, slope stability, and earthquake response.

Outputs include borehole logs, test results, and a geotechnical report with recommendations for foundation types, allowable bearing pressures, ground improvement, and construction considerations. Sonderingen are conducted by geotechnical engineers or geologists in accordance with national and industry standards and serve as the basis for safe and economical design of subsurface works.