A case study of rainfall‐triggered slope instability using projected extremes

Abstract

<jats:title>Abstract</jats:title><jats:p>In the past years due to climate change the region of South‐East Europe is subjected to extreme weather events with intense rainfall fallowed by activation or reactivation of landslides. In this paper a rainfall‐triggered landslide is investigated on extreme precipitation estimates. Hence, the behaviour of the slope is controlled by the hydro‐mechanical conditions and soil‐atmosphere interaction. In this case study a slope stability of a natural landslide is calculated for projected rainfall of 10 mm/h with 24‐hour duration. In such scenarios due to the excess pore‐water pressure even deep‐sited landslides beside local can exhibit global instability. This study aims to quantitatively assess the impact of intense rainfall on the landslides. The extreme precipitation pattern is considered as loading condition in a fully coupled hydromechanical finite element simulation, where the displacements, matric suctions, and suction stresses are calculated. The results indicate that intense rainfall leads to fast pore‐water pressure build‐up resulting in local strength reduction of the slope. In general, the findings urge to reassess the existing risk maps with more detailed models and higher prognosed precipitation.</jats:p>