Management of quick clay areas in slope stability investigations – the göta river valley

Abstract

In order to limit the vulnerability of society to effects of the climate change, the Swedish Government in 2008 commissioned the Swedish Geotechnical Institute to map the risk of landslides along the Göta River. The Göta River valley is one of the areas most prone to landslides in Sweden. Since it is an area with highly sensitive clays, mapping of quick clay areas and estimation of possible landslide extent were important parts of the investigation. In the Göta River Commission, a correlation between the sensitivity and the total rod friction evaluated from CPTs and static pressure sounding tests was used as a complement to sampling for mapping of quick clay areas. If a landslide is initiated in an area with quick clay the probability is high that it will propagate and affect areas nearby. Within the Göta River Commission, estimates of how far a landslide would extend backwards was made taking into account the slope geometry and the sensitivity of the clay, partly based on analyses of earlier occurred landslides. A methodology was developed for rational management of quick clay areas in the stability investigations for the Göta River valley.