| dc.description.abstract | Comprehensive evaluation of the vibrations transmitted to the site from external sources constitute a significant environmental facet of building and facility design. External sources include, but are not limited to railways, machinery, highway traffic, and quarrying operations. The vibrations magnitudes is crucial to assess if we aim to properly predict the levels of excitation at buildings near vibration sources. However, predicting vibrations in terms of both amplitudes and frequency is problematic. This complication occurred due to the lack of a full understanding of seismic wave propagation in soil, uncertainty of soil properties, and the lack of accurate models for vibration sources and the resulting near-and far-field behavior. Nevertheless, in spite of these and other obstacles, it is conceivable to use available empirical and numerical data to make realistic assessments of the propagating waves. Blast vibrations are an inescapable occurrence in the vicinity of quarries, if blasting techniques are used in quarrying operations. Vibrations may degrade the environment, and cause annoyance to the population in the neighborhood of the quarry.
In the study area, it has been found that the changes in the peak particle velocity (PPV) is more influenced by the degree of consolidation and the direction of fractures rather than by the types of lithology. Given the fact that, the tectonics’ normal fault will produce two types of zones, the consolidated (downthrown, up thrown) and the unconsolidated, the analysis of the PPV and frequency was attributed to the mechanism of wave propagation in the body of these materials. Furthermore, due to the coverage of a large range of measurements and the complex tectonics involved, 5 propagation mechanisms have been proposed for the explanation of the data. Effect of fractures and fluid saturations and faults has been incorporated in the analysis.
There are no significant lithology differences inside each of the specified zones, so the wave propagation in each material was not considered as a tool to differentiate between the different zones. However, different locations in the same zone showed an amplification and attenuation in the PPV, even though they were measured at the same scaled distance (equal blasting energy). This was attributed to the transmission of the wave at the boundary (sedimentary contact or fracture) for different formations such as limestone and clay (the predominant lithology in the area).
This thesis is describing the process of different model constructions and validations for the five mechanisms using empirical and numerical models. A qualitative geological interpretation has been given, exploiting the optimized parameters of the models. | en |
