| Small perturbation techniques permit testing geo-materials and geo-processes without altering the measured parameters. Active and passive measurements, involving both mechanical and electromagnetic waves, can be used to obtain unique information about material behavior and to monitor processes in engineering practice.; This thesis centers on the study of three geo-phenomena that have received little attention in the past: wave propagation in jointed rock masses at low confinement (including both velocity and attenuation), dynamic energy coupling in soils, and dynamic energy coupling in rocks. Developments include the modeling of the low strain response of rock masses with micro-mechanical models, the development of conceptual yet robust models to explain the dynamic energy coupling in soil and fracto-emissions in rocks, and corresponding laboratory experiments to uniquely assess these phenomena.; Thereafter, the application of active-passive wave phenomena in practice is investigated in the context of two engineering problems. First, it is shown that electromagnetic fracture emission allows obtaining the location of sources in space and monitoring the evolution of the fracture in the three dimensional space. Second, a robust methodology is developed to tomographically image the presence of low velocity anomalies (the weak element in geotechnical and structural systems). This study includes straight rays, curved rays, and a simple diffraction model. A solution is found using both amplitude and travel time data within matrix and parametric inversions.; Results from this research show that the unique coupling of mechanical processes with electromagnetic phenomena can support the development of innovative engineering tools while at the same time shed light on the behavior of geomaterials. |
