Application of the PWP-Tester for the analysis of the evolution of the excess pore water pressure in cyclic loaded soils

• Applicant: Professor Dr.-Ing. Ivo Herle
• Subject Area: Geotechnics, Hydraulic Engineering
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 559147838

The investigation of pore water pressure (PWP) build-up under cyclic loading for various soils is typically conducted through triaxial or direct shear tests. These experiments are time-consuming and can only be performed in specially equipped laboratories. The PWP Tester, newly developed by the applicant, enables a rapid, efficient, and systematic examination of the PWP build-up (not only) in coarse-grained soils, and therefore can be considered as a potential alternative to the aforementioned complex testing methods. The proposed project aims to further explore the possible applications of the PWP Tester. In addition to the current setup, the measurement of shear force will be integrated to obtain a more comprehensive understanding of the stress-strain behavior of soils under both monotonic and cyclic shear loading conditions. The experiments will be conducted not only under undrained conditions but also under drained conditions. Moreover, the scope of application of the PWP Tester will be extended by including additional soil types. This will allow for the investigation of the PWP build-up during shearing under undrained conditions and the associated softening under cyclic loading particularly in fine-grained soils. The PWP Tester will also be employed for the quick calibration of advanced constitutive models, thereby supporting the development and critical evaluation of new material models. The assessment of test data, such as the degradation of the shear modulus with increasing shear strain amplitude and the evolution of the PWP under cyclic loading, will form the basis of the calibration process. Finally, cyclic loading scenarios comprising sequences of irregular shear strain amplitudes will be analyzed. This approach allows for the realistic simulation of earthquake signals, enabling rapid analyses of various loading scenarios. Such analyses can also contribute to a more refined definition of equivalent regular cyclic packages as substitute loading conditions.

• DFG Programme: Research Grants