Pre-study: Ground Improvement for Marginally Stable Slopes

Report, 2014

The report aims to give a critical review on various ground improvement methods that involve in-situ mixing and/or injection of stabilising agents in the form of powder or slurry into soft clays. The project was initiated by Norwegian Public Roads Administration (NPRA), given the problems in Norway associated with slopes of marginal stability. This project is also a part of the Natural hazards – infrastructure for floods and slides (NIFS) project initiated by the Norwegian National Rail Administration (JBV), the Norwegian Water Resources and Energy Directorate (NVE) and the Norwegian Public Roads Administration (NPRA).The report will focus on installation methods that are applicable for ground improvement in soft sensitive clays, with the aim of identifying installation methods that minimise pore pressure build-up during installation as well as deformations. The methods considered include both dry and wet deep soil mixing and various other potential methods, including electro-osmotic injection of stabilising agents into the soft soil. Additionally, an evaluation of the achieved effect on strength parameters resulting from the use of wet slurry versus dry mixing is conducted.