Rheometrical experiments with monitoring of resistivity and induced polarization: For a better understanding of the solid-fluid transition in clayey landslides

摘要

Clayey landslides acting like debris-flows when experiencing fluidization represent serious threats for populations and infrastructures and have been the subject of numerous works in the past decade. Recent studies have shown that the shear-wave velocity V_s (linked to the stiffness of the material), could potentially be used as a precursory parameter for earthflow activation. However, the transient mechanism explaining this precursory behavior remains uncertain and the solid-fluid transition is still poorly understood. A complementary way to understand these processes is to monitor electrical clay parameters such as resistivity and induced polarization. It is well known that these electrical parameters are sensitive to the clay water content, pore tortuosity and connectivity, which are likely to exhibit some changes during fluidization. Rheometrical experiments with electrical measurements have been performed on clay samples coming from four flow-like landslides of the Alpes. The results show that 1) resistivity does not seem to be sensitive to the clay fluidization and 2) Induced polarization seem to be sensitive to this transition. These new results and what they entail in terms of solid-fluid transition mechanisms are discussed in this paper.