Tidsberoende effekter av schakt i lös lera

Research Project, 2018 – 2020

When soil is unloaded, time-delayed effective stress changes occur. In soils with low permeability such as clay, the changes can take considerable time. The subsequent effects on soil properties and forces acting on constructions are thus time-dependent. As a consequence of more efficient construction methods, an increased proportion of the stress changes will occur after the construction phase, as well as the magnitudes of unloading will increase due to deeper excavations. Existing methods of analyses are often based on simplified assumptions, combined with inadequate empirical knowledge, which poses a potential risk.

The aim of the project is to increase knowledge about the effects of unloading of clays, focusing on time-dependency, in the context of deep excavations. It also aims to identify if measurement data differs from the expected values based on current calculation methods.

The project is conducted as an industrial PhD project at Chalmers. The project until Lic exam can be summarized as: review of potential case studies, advanced laboratory testing, field measurements and analysis.

The project results will strengthen geotechnical knowledge and facilitate function-oriented design of geotechnical works, especially design related to deep excavations and/or shorter construction times that the construction industry faces. Overall, the project is expected to contribute to optimized and safer design, reduced maintenance costs and predictable environmental impact.