Djupstabilisering i stadsmiljö

Research Project, 2020 – 2023

With increasing urbanisation, there is an increasing need to construct underground. Most foundation structures are made of concrete, with high embodied CO2. Thus, there is a need for alternative solutions. In deep mixing (DM) stabilising agents (cement, lime and waste products) are mixed to the soil in-situ, using the particles and the water in the soft soil in complex chemical reactions, resulting in weakly cemented rigid inclusions. DM results in no spoil, eases the excavation of soft sediments and offers excellent adaptivity for future re-use of foundations. DM offers thus both environmental and socio-economic benefits. DM is now common under embankments. More recently DM has been adapted as support against bottom up-lift in deep excavations, instead of cross walls made of concrete. As the current design guidelines do not cover this new application area, expensive field demonstrations have recently been made in Sweden to study feasibility. To generalise these results, and to enable optimisation of the design in future projects, effective computational modelling techniques are needed. The method proposed is a rigorous computational homogenisation technique that allows modelling complex 3D soil-structure interaction problems with computationally efficient 2D analyses. The project is timely, contributing to sustainable development and digitisation agenda. It provides a scientific base for enabling sustainable design of deep excavations in urban areas.