Skip to main content

Effects of wetting and drying cycles on landslide activity

Final Report Summary - WANDLAND (Effects of wetting and drying cycles on landslide activity)

The purpose of this project was to improve the capabilities to understand and predict the occurrence of landslide crisis episodes associated with alternated rainfall patterns. Landslides are among the most severe problems that affect mankind in terms of loss of human life, damages to infrastructure and irreversible changes of natural environment. The situation is even more alarming when forecasts on clime evolution are taken into account and considering the associated changes in hydrological cycles and rainfall patterns (more extreme rainfall events and concentrated rain within shorter periods of time are expected). Despite the expected impacts, many issues have yet to be addressed to develop tools and methodologies able to protect people and property from these growing natural hazards.

From a geomechanical prospective, the link between the rainfall patterns and landslide occurrences is related to both the heavy modifications of pore fluid pressure distributions associated with these phenomena and the consequent changes in available shear strength within the slope. However, this kind of phenomena cannot be the only key to fully understanding the failure processes, especially in regions where extreme events are not exceptional. In these cases, failures sometimes occur in conjunction with rainfall whose features (intensity and duration) are not the most severe ones recorded for the particular area. In this context, establishing a warning system based on rainfall intensity and duration could be inappropriate. Considering the previous drying and wetting cycles which involved the soils is of crucial importance. In this context WANDLAND focused on the geomechanical impact of wetting and drying cycles in shallow landslides activity.

Three main components were considered and addressed in this project, namely:
A. Improvement of the constitute analysis of natural soil geomechanical behaviour associated with wetting/drying cycles;
B. Development of advanced experimental setup to quantify the mechanical response of natural soils under variations of their degree of saturation (or suction);
C. Advanced numerical modelling of rainfall induced landslides for an improved understanding of the triggering mechanisms and the establishment of early warning systems.