Back-calculation of settlements from large road embankments on clay

The fill height is up to 13 m on locally sensitive clay with a thickness of up to 40 m. To reduce the risk of settlements after completion, measures for strengthening the foundation soil have been carried out, such as lime cement stabilization, vertical drainage, and preloading. One goal has been to minimize the extent of lime cement with a high CO2 footprint by using the gradual strength build-up of the clay by consolidation.

The task

The first phase of the task will be to calculate the settlements obtained and compare them with interpretations from field and laboratory investigations. This can be done in GeoSuite or PLAXIS.

Depending on the results from the first phase, several possible approaches will then be considered. One approach may be to examine the effect of lime-cement stabilization on settlements and the stress distribution in clay stabilized by lime-cement.

Another approach could be to study the effect of vertical drainage on the settlements and the resulting strength build-up due to consolidation.

This thesis provides scope for investigating topics of great importance for geotechnical engineering in Norway. Lime-cement stabilization is widespread in Norway as soil reinforcement, particularly for sensitive clay. However, this method has a high CO2 footprint, and projects should, therefore, strive to minimize the extent of the use of lime cement.