Quantifying the Effect of Fluids and Mechanical Weakening of Fractures and the Implications for the Rupture of Large Landslides

Landslides are sensitive to fluid pressures generated by rainfall and snowmelt. Correlations between landslides accelerations and seasonal infiltrations have been widely observed, and models have shown that fluid pressurization in fractures is a dominant driving factor. Nevertheless the precise mechanisms relating fluid pressures and rupture are poorly constrained. Here, we quantified in-situ the effect of fluids and strength loss related to pressure increase and deformation in fractures. Then, using hydromechanical modeling, we analyzed these data and explained the evolution of permeability with deformation. Finally, based on these novel observations, we used improved hydromechanical simulations to model the behaviour of the Schilienne landslide in France.