Electrical Methods and Geotechnical Engineering to Evaluate Slope Stability: Case Study for a Site Located in Tijuana Metropolitan Area.

Abstract:

Rotational landslides are a serious problem in the metropolitan area of Tijuana, urban development has occurred in areas where terrain instability is a latent threat. The characterization of a landslide requires a multidisciplinary approach to relate geological processes with soil mechanical parameters. Connection between these factors is not common in slope stability modeling, the usual practice is to separately asses geophysical and geotechnical methods. In this study, electrical resistivity models in 3D, 2D and induced polarization where used to compliment information from bore holes (drilled to a depth of 20 m) and laboratory tests conducted in representative soil samples recovered on site. The study area is located in the central South portion of Tijuana metropolitan area, its lithology has a sedimentary origin, therefore there was little variation in resistivity values. The coupling of resistivity models with bore hole logs and soil mechanical parameters obtained from lab tests, made it possible to come up with stratigraphic profiles to compute slope stability, even in areas where bore holes were not drilled. Results from our slope stability computations allowed us to identify areas where earthworks and other contention measurements are required.