Modelling the control of groundwater on landslides triggering: the respective role of atmosphere and rainfall during typhoons
Journal article, 2022

Landslides are often triggered by catastrophic events, among which earthquakes and rainfall are the most depicted. However, very few studies have focused on the effect of atmospheric pressure on slope stability, even though weather events such as typhoons are associated with significant atmospheric pressure changes. Indeed, both atmospheric pressure changes and rainfallinduced groundwater level change can generate pore pressure changes with similar amplitude. In this paper, we assess the respective impacts of atmospheric effects and rainfall over the stability of a hillslope. An analytical model of transient groundwater dynamics is developed to compute slope stability for finite hillslopes. Slope stability is evaluated through a safety factor based on the Mohr-Coulomb failure criterion. Both rainfall infiltration and atmospheric pressure variations, which impact slope stability by modifying the pore pressure of the media, are described by diffusion equations. The models have then been forced by weather data from different typhoons that were recorded over Taiwan. While rainfall infiltration can induce pore pressure change up to hundred kPa, its effects is delayed in time due to diffusion. To the contrary, atmospheric pressure change induces pore pressure changes not exceeding a few kPa, but its effect is instantaneous. Moreover, the effect of rainfall infiltration on slope stability decreases towards the toe of the hillslope and is cancelled where the water table reaches the surface, leaving atmospheric pressure change as the main driver of slope instability. This study allows for a better insight of slope stability through pore pressure analysis, and shows that atmospheric effects shouldn’t always be neglected.

Author

Lucas Pelascini

University of Rennes 1

Philippe Steer

University of Rennes 1

Maxime Mouyen

Chalmers, Space, Earth and Environment, Geoscience and Remote Sensing

Laurent Longuevergne

University of Rennes 1

Natural Hazards and Earth System Science

1561-8633 (ISSN) 1684-9981 (eISSN)

Subject Categories

Meteorology and Atmospheric Sciences

Physical Geography

Probability Theory and Statistics

DOI

10.5194/nhess-2021-340

More information

Latest update

10/26/2023