Development of a Large-Scale Geotechnical Calibration Chamber for Controlled Cone Penetration Testing

Abstract

Cone penetration tests (CPT) are widely established for geotechnical site investigation due to their cost-effectiveness and rapid deployment. However, the derivation of geotechnical design parameters from CPT data remains insufficiently standardized within the current German framework (DIN 1997-2:2010-10 and DIN 4020:2010-12). Existing empirical correlations are often limited to specific soil types and depositional conditions and are not directly applicable to many non-cohesive soils found in northern Germany. To address this gap, the BAW, in cooperation with HSU, is developing a large-scale geotechnical calibration chamber for controlled laboratory CPT investigations. The cylindrical chamber, with an internal diameter of 1.9 m and a height of 2.3 m, is designed to minimize boundary effects and enable testing in homogeneous sand specimens of known density and grain size distribution. Specimens will be prepared using an integrated air pluviation unit that produces a uniform sand rain and allows reproducible densities. The feasibility of pluviation under vacuum conditions is also being investigated. Independent application of axial and radial stresses, as well as saturation, will enable testing under various stress and drainage conditions. Although still in the final design phase, the facility will provide the basis for systematic CPT studies and the development of improved soil-specific correlations for non-cohesive soils.