Site investigation and modelling of earthquake-induced rock slides in central-southern Chile

摘要

Analyses of three case studies of earthquake-induced rock slides in central and southern Chile are presented. The case studies are located in different latitudes, local tectonic environments, and geomorphological contexts of the Andes (Santiago Main Cordillera at 33ºS, Concepción Coastal Cordillera at 37ºS, and Patagonia Fjordland at 45ºS), with different rock types exhibiting various failure modes which were related to different earthquake motions. The methodology includes procurement of already available and new high-resolution digital elevation models of the slide surfaces from terrestrial laser scanning, terrestrial and airborne (drone) photogrammetry, seismic surveys, as well as acquisition of available and new geotechnical data of the intact rock and rock mass structure. The data are being used to construct 2D and 3D geological models for slope modelling using commercial limit equilibrium and distinct elements codes; modelling of seismic inputs from real and synthetic ground motion; and time domain dynamic slope stability analyses using distinct element techniques. The results will allow a more comprehensive understanding of dynamic slope response of large rock slopes during earthquakes, including the influence of geological, geotechnical, geometric and strong motion factors on slope instability and the role of site-specific effects on the triggering of slope failures.