Adhesion between plane steel surfaces and fine-grained soils

• Applicants: Professor Dr.-Ing. Jürgen Grabe; Professor Dr.-Ing. Marius Milatz
• Subject Area: Geotechnics, Hydraulic Engineering
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 516859143

A deeper understanding of the contact surface between a structure or tool and the surrounding soil is fundamental for many geotechnical applications. Applications range from pile structures, which mobilise their load-bearing capacity via their shaft, to cutter heads of tunnel boring machines, whose advance rate is significantly characterised by the conditions in the interface with the ground. In most geotechnical applications, the Mohr-Coulomb friction law is used to describe the interaction between soil and structural surface. For coarse-grained soils this approach is applicable, but for fine-grained soils the behaviour in the interface is much more complex. Adhesion and stickiness of the material occur and there seem to be forces in the interface that are not only related to friction. To date, there is no satisfactory model that can fully represent the behaviour between a steel surface and a fine-grained soil. One of the aims of the present research project is to create an experimental database that allows models of the interfacial behaviour between fine-grained soils and steel to be derived. This is based on an extensive experimental programme with specialised experimental techniques and controlled sample preparation. Based on the findings, numerical modelling approaches for the interface will be developed. The developed models can be applied in many geotechnical problems, such as tensile piles in fine-grained soils as well as adhesion phenomena occurring in mechanised tunnelling. The consideration of adhesion can lead to a more economical design and the possibility to simulate adhesion could enable a better prediction of tool clogging as a function of soil properties.

• DFG Programme: Research Grants