The Randa Rockslide Laboratory: establishing brittle and ductile instability mechanisms using numerical modelling and microseismicity

摘要

The underlying complexity associated with unstable massive rock slopes has generally restricted the investigation of such slopes to phenomenological studies that are largely descriptive and qualitative. Continued rockslide problems experienced throughout mountainous regions of the world, however, demonstrate the need for a deeper understanding of the physical processes and mechanisms leading to catastrophic failure. This paper focuses on the role brittle fracture and plastic deformation processes play in the development of catastrophic failures in massive, crystalline rock slopes. The work presented is based on the 1991 Randa rockslide in southern Switzerland and combines several conceptual and numerical models developed with respect to tensile and shear mechanisms that drive progressive rock slope failure. The paper also presents preliminary microseismic monitoring results recorded through the Randa Rockslide Laboratory, a unique multidisciplinary alpine facility focusing on ongoing movements at Randa. Such data are expected to provide valuable constraints for specialized hybrid finite-/discrete-element modelling designed to explicitly model rock slope deformation, damage initiation and fracture propagation.