Employment of elastic and electromagnetic waves aimed at geotechnical characterization of partially saturated soils on land susceptible to landslides

Abstract

The field record of electromagnetic and elastic waves in shallow geophysical investigation allows determining important parameters of soils, their spatial distribution, and temporal variation. Therefore, it can generate subsidies for geotechnical studies of soils and sediments. This research plan aims at a deeper understanding of the shallow subsurface through the study of relations between the elastic and electromagnetic properties with soil parameters obtained by analysis of two aspects of wave propagation phenomenon: (i) of path waves considering different components of motion (P and S elastic waves, and electromagnetic waves acquired in the transverse electric and magnetic modes) in order to the imaging of shallow subsurface, (ii) and their attributes (velocity and attenuation) seeking correlations with the petrophysical parameters of medium. The potential of application of this study will be tested in trial field in São Paulo state presenting natural susceptibility to the occurrence of landslides and where research project is developed with the monitoring of climate and geotechnical variables and the execution of various and geotechnical tests on disturbed and undisturbed soil samples. These data allow obtaining important inputs for geophysical data processing. It is intended to perform numerical and experimental studies as well as processing of data collected in an experimental field on studies period at the Department of Geoscience & Engineering of Faculty of Civil Engineering and Geosciences (CiTG) of Technology University of Delft (TUDelft) under the supervision of Professor Evert Slob (electromagnetic methods) and co-supervision of Professor Ranajit Ghose (seismic methods). These studies will focus on complete inversion and analysis of electromagnetic wave dispersion, relations of dependence between S wave velocity and effective vertical and horizontal stress levels, inversion of velocity and attenuation attributes of elastic waves considering the dispersive nature of the propagation pore-elastic medium. (AU)