Simplified quantitative risk assessment of rainfall-induced landslides modelled by infinite slopes

• Loss of suction and generation of positive pore water pressure cause landslides.
• Risk of landslides is assessed quantitatively.
• Critical spatial correlation length exists at which the risk is maximum.
• Higher risk when failure is due to generation of positive pore water pressure.

Rainfall induced landslides vary in depth and the deeper the landslide, the greater the damage it causes. This paper investigates, quantitatively, the risk of rainfall induced landslides by assessing the consequence of each failure. The influence of the spatial variability of the saturated hydraulic conductivity and the nature of triggering mechanisms on the risk of rainfall-induced landslides (for an infinite slope) are studied. It is shown that a critical spatial correlation length exists at which the risk is a maximum and the risk is higher when the failure occurs due to a generation of positive pore water pressure.