Rate-dependency of residual shear strength of soils: implications for landslide evolution

Shear-rate weakening or strengthening behaviours can effectively control landslide runouts, defining sudden runaway sliding or years-long slow-creep phases. These behaviours are partly controlled by the properties of the basal material. Understanding its stress–strain–time response is crucial in physically-based assessments of landslide dynamics and the associated risk. We investigate the frictional resistance of a calcium bentonite, a kaolin and a quartz sand by means of a conventional ring-shear apparatus under normal stresses representative of landslide shear zones. Results for the fine-grained soils, in line with literature on pure clays, indicate important velocity strengthening, whereas small shear-rate effects were observed in sand. As long as effective stresses remain constant, a velocity strengthening response can exert a feedback that, under certain conditions, counteracts perturbations in boundary conditions and prevents fast runouts on pre-existing shear zones. Accordingly, we argue that specifically testing for shear-rate-dependency and incorporating observed behaviours in model formulations can be beneficial for better predicting landslide fates.

• Autores: Duque, J.; Loche, M.; Scaringi, G.
• Tipo de recurso: Article of investigation
• Fecha de publicación: 2023
• Institución: Corporación Universidad de la Costa
• Repositorio: REDICUC - Repositorio CUC
• Idioma: eng
• OAI Identifier: oai:repositorio.cuc.edu.co:11323/10567
• Acceso en línea: https://hdl.handle.net/11323/10567; https://repositorio.cuc.edu.co/
• Palabra clave: Landslide; Residual shear strength; Shear-rate effect; Velocity strengthening; Velocity weakening
• Rights: embargoedAccess
• License: Atribución 4.0 Internacional (CC BY 4.0)